)]}'
{
  "log": [
    {
      "commit": "a637120e49021d197e9578cba545bbaa459cbb51",
      "tree": "0d502a8fcc55c89eb4d79a7578e46a9273d1f2c8",
      "parents": [
        "496fb7806d616185a46865a4f3a20ef19dc6c7e3"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Thu Apr 19 16:29:24 2012 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Fri Apr 20 10:06:40 2012 +0200"
      },
      "message": "blkcg: use radix tree to index blkgs from blkcg\n\nblkg lookup is currently performed by traversing linked list anchored\nat blkcg-\u003eblkg_list.  This is very unscalable and with blk-throttle\nenabled and enough request queues on the system, this can get very\nugly quickly (blk-throttle performs look up on every bio submission).\n\nThis patch makes blkcg use radix tree to index blkgs combined with\nsimple last-looked-up hint.  This is mostly identical to how icqs are\nindexed from ioc.\n\nNote that because __blkg_lookup() may be invoked without holding queue\nlock, hint is only updated from __blkg_lookup_create().  Due to cfq\u0027s\ncfqq caching, this makes hint updates overly lazy.  This will be\nimproved with scheduled blkcg aware request allocation.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "f9fcc2d3919b8eb575b3cee9274feefafb641bca",
      "tree": "bb3eaeb993b21ba352c0967488a6955a40314d97",
      "parents": [
        "f95a04afa80c0f4ddd645ef6a84ed118b5d1ad46"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Apr 16 13:57:27 2012 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Fri Apr 20 10:06:17 2012 +0200"
      },
      "message": "blkcg: collapse blkcg_policy_ops into blkcg_policy\n\nThere\u0027s no reason to keep blkcg_policy_ops separate.  Collapse it into\nblkcg_policy.\n\nThis patch doesn\u0027t introduce any functional change.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "f95a04afa80c0f4ddd645ef6a84ed118b5d1ad46",
      "tree": "2428dacf9bab1eb643628c872aed3092704f7fb2",
      "parents": [
        "3c798398e393e5f9502dbab2b51e6c25e2e8f2ac"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Apr 16 13:57:26 2012 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Fri Apr 20 10:06:17 2012 +0200"
      },
      "message": "blkcg: embed struct blkg_policy_data in policy specific data\n\nCurrently blkg_policy_data carries policy specific data as char flex\narray instead of being embedded in policy specific data.  This was\nforced by oddities around blkg allocation which are all gone now.\n\nThis patch makes blkg_policy_data embedded in policy specific data -\nthrotl_grp and cfq_group so that it\u0027s more conventional and consistent\nwith how io_cq is handled.\n\n* blkcg_policy-\u003epdata_size is renamed to -\u003epd_size.\n\n* Functions which used to take void *pdata now takes struct\n  blkg_policy_data *pd.\n\n* blkg_to_pdata/pdata_to_blkg() updated to blkg_to_pd/pd_to_blkg().\n\n* Dummy struct blkg_policy_data definition added.  Dummy\n  pdata_to_blkg() definition was unused and inconsistent with the\n  non-dummy version - correct dummy pd_to_blkg() added.\n\n* throtl and cfq updated accordingly.\n\n* As dummy blkg_to_pd/pd_to_blkg() are provided,\n  blkg_to_cfqg/cfqg_to_blkg() don\u0027t need to be ifdef\u0027d.  Moved outside\n  ifdef block.\n\nThis patch doesn\u0027t introduce any functional change.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "3c798398e393e5f9502dbab2b51e6c25e2e8f2ac",
      "tree": "d6f638e6a25dec4887e64bcc35b98bc394cb974f",
      "parents": [
        "36558c8a30e121f97b5852ae33e28081af21bdbf"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Apr 16 13:57:25 2012 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Fri Apr 20 10:06:17 2012 +0200"
      },
      "message": "blkcg: mass rename of blkcg API\n\nDuring the recent blkcg cleanup, most of blkcg API has changed to such\nextent that mass renaming wouldn\u0027t cause any noticeable pain.  Take\nthe chance and cleanup the naming.\n\n* Rename blkio_cgroup to blkcg.\n\n* Drop blkio / blkiocg prefixes and consistently use blkcg.\n\n* Rename blkio_group to blkcg_gq, which is consistent with io_cq but\n  keep the blkg prefix / variable name.\n\n* Rename policy method type and field names to signify they\u0027re dealing\n  with policy data.\n\n* Rename blkio_policy_type to blkcg_policy.\n\nThis patch doesn\u0027t cause any functional change.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "36558c8a30e121f97b5852ae33e28081af21bdbf",
      "tree": "de9b361baf71b0b893d4053ac061f8e160ecfd37",
      "parents": [
        "54e7ed12bad1e3aa2a28558fab6850240465f973"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Apr 16 13:57:24 2012 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Fri Apr 20 10:06:16 2012 +0200"
      },
      "message": "blkcg: style cleanups for blk-cgroup.h\n\n* Update indentation on struct field declarations.\n\n* Uniformly don\u0027t use \"extern\" on function declarations.\n\n* Merge the two #ifdef CONFIG_BLK_CGROUP blocks.\n\nAll changes in this patch are cosmetic.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "54e7ed12bad1e3aa2a28558fab6850240465f973",
      "tree": "907eb0451782f4eb1ad3f9236e51ec4acb7fb941",
      "parents": [
        "c94bed89995e638e43a6663177358b9d20617361"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Apr 16 13:57:23 2012 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Fri Apr 20 10:06:16 2012 +0200"
      },
      "message": "blkcg: remove blkio_group-\u003epath[]\n\nblkio_group-\u003epath[] stores the path of the associated cgroup and is\nused only for debug messages.  Just format the path from blkg-\u003ecgroup\nwhen printing debug messages.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "c94bed89995e638e43a6663177358b9d20617361",
      "tree": "901c1a4aa7cde07cb921889b94ea2cafd15e79b7",
      "parents": [
        "6d18b008daf46bcd82b8ae250aae0785f9714096"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Apr 16 13:57:22 2012 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Fri Apr 20 10:06:16 2012 +0200"
      },
      "message": "blkcg: blkg_rwstat_read() was missing inline\n\nblkg_rwstat_read() in blk-cgroup.h was missing inline modifier causing\ncompile warning depending on configuration.  Add it.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "3c96cb32d318f323c1bf972a4c66821f8499e34d",
      "tree": "e76d0437f487405d8a22a727b8085696b949179d",
      "parents": [
        "a2b1693bac45ea3fe3ba612fd22c45f17449f610"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Fri Apr 13 13:11:34 2012 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Fri Apr 20 10:06:06 2012 +0200"
      },
      "message": "blkcg: drop stuff unused after per-queue policy activation update\n\n* All_q_list is unused.  Drop all_q_{mutex|list}.\n\n* @for_root of blkg_lookup_create() is always %false when called from\n  outside blk-cgroup.c proper.  Factor out __blkg_lookup_create() so\n  that it doesn\u0027t check whether @q is bypassing and use the\n  underscored version for the @for_root callsite.\n\n* blkg_destroy_all() is used only from blkcg proper and @destroy_root\n  is always %true.  Make it static and drop @destroy_root.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "a2b1693bac45ea3fe3ba612fd22c45f17449f610",
      "tree": "2e05859caab6453efbc85d584dd72dca7ef03cd0",
      "parents": [
        "03d8e11142a893ad322285d3c8a08e88b570cda1"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Fri Apr 13 13:11:33 2012 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Fri Apr 20 10:06:06 2012 +0200"
      },
      "message": "blkcg: implement per-queue policy activation\n\nAll blkcg policies were assumed to be enabled on all request_queues.\nDue to various implementation obstacles, during the recent blkcg core\nupdates, this was temporarily implemented as shooting down all !root\nblkgs on elevator switch and policy [de]registration combined with\nhalf-broken in-place root blkg updates.  In addition to being buggy\nand racy, this meant losing all blkcg configurations across those\nevents.\n\nNow that blkcg is cleaned up enough, this patch replaces the temporary\nimplementation with proper per-queue policy activation.  Each blkcg\npolicy should call the new blkcg_[de]activate_policy() to enable and\ndisable the policy on a specific queue.  blkcg_activate_policy()\nallocates and installs policy data for the policy for all existing\nblkgs.  blkcg_deactivate_policy() does the reverse.  If a policy is\nnot enabled for a given queue, blkg printing / config functions skip\nthe respective blkg for the queue.\n\nblkcg_activate_policy() also takes care of root blkg creation, and\ncfq_init_queue() and blk_throtl_init() are updated accordingly.\n\nThis replaces blkcg_bypass_{start|end}() and update_root_blkg_pd()\nunnecessary.  Dropped.\n\nv2: cfq_init_queue() was returning uninitialized @ret on root_group\n    alloc failure if !CONFIG_CFQ_GROUP_IOSCHED.  Fixed.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "da8b066262e12d1d0a3b1e6d3486e500169bf730",
      "tree": "048eee7101b526017bbd295366bf2e95dd65e5a7",
      "parents": [
        "8bd435b30ecacb69bbb8b2d3e251f770b807c5b2"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Fri Apr 13 13:11:29 2012 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Fri Apr 20 10:06:06 2012 +0200"
      },
      "message": "blkcg: make blkg_conf_prep() take @pol and return with queue lock held\n\nAdd @pol to blkg_conf_prep() and let it return with queue lock held\n(to be released by blkg_conf_finish()).  Note that @pol isn\u0027t used\nyet.\n\nThis is to prepare for per-queue policy activation and doesn\u0027t cause\nany visible difference.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "8bd435b30ecacb69bbb8b2d3e251f770b807c5b2",
      "tree": "a1a50e95517a54a578af3967fb4016a5a1a42a68",
      "parents": [
        "ec399347d39fb2337ebace928cf4a2855bd0ec37"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Fri Apr 13 13:11:28 2012 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Fri Apr 20 10:06:06 2012 +0200"
      },
      "message": "blkcg: remove static policy ID enums\n\nRemove BLKIO_POLICY_* enums and let blkio_policy_register() allocate\n@pol-\u003eplid dynamically on registration.  The maximum number of blkcg\npolicies which can be registered at the same time is defined by\nBLKCG_MAX_POLS constant added to include/linux/blkdev.h.\n\nNote that blkio_policy_register() now may fail.  Policy init functions\nupdated accordingly and unnecessary ifdefs removed from cfq_init().\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "ec399347d39fb2337ebace928cf4a2855bd0ec37",
      "tree": "d95efeb004e8da914f7d3c726cd059b422443694",
      "parents": [
        "bc0d6501a844392ab6ad419d7ca5af4693b6afac"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Fri Apr 13 13:11:27 2012 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Fri Apr 20 10:06:06 2012 +0200"
      },
      "message": "blkcg: use @pol instead of @plid in update_root_blkg_pd() and blkcg_print_blkgs()\n\nThe two functions were taking \"enum blkio_policy_id plid\".  Make them\ntake \"const struct blkio_policy_type *pol\" instead.\n\nThis is to prepare for per-queue policy activation and doesn\u0027t cause\nany functional difference.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "bc0d6501a844392ab6ad419d7ca5af4693b6afac",
      "tree": "08375aff242a2efd35d830c7636ab61a3ec6a109",
      "parents": [
        "f48ec1d7885281a9c6cd7779d61f321d1b1fd741"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Fri Apr 13 13:11:26 2012 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Fri Apr 20 10:06:06 2012 +0200"
      },
      "message": "blkcg: kill blkio_list and replace blkio_list_lock with a mutex\n\nWith blkio_policy[], blkio_list is redundant and hinders with\nper-queue policy activation.  Remove it.  Also, replace\nblkio_list_lock with a mutex blkcg_pol_mutex and let it protect the\nwhole [un]registration.\n\nThis is to prepare for per-queue policy activation and doesn\u0027t cause\nany functional difference.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "f48ec1d7885281a9c6cd7779d61f321d1b1fd741",
      "tree": "87f94a60dae017dc68b76605f76b89031004a7f7",
      "parents": [
        "5bc4afb1ec6aa562fac4d9aba34d957ee42f5813"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Fri Apr 13 13:11:25 2012 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Fri Apr 20 10:06:06 2012 +0200"
      },
      "message": "cfq: fix build breakage \u0026 warnings\n\n* CFQ_WEIGHT_* defined inside CONFIG_BLK_CGROUP causes cfq-iosched.c\n  compile failure when the config is disabled.  Move it outside the\n  ifdef block.\n\n* Dummy cfqg_stats_*() definitions were lacking inline modifiers\n  causing unused functions warning if !CONFIG_CFQ_GROUP_IOSCHED.  Add\n  them.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "5bc4afb1ec6aa562fac4d9aba34d957ee42f5813",
      "tree": "dfef1de2dcb71beab3150ffecf6ae564d326ffba",
      "parents": [
        "d366e7ec41882791c970dfb7c67b737be8c3a174"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:45 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:45 2012 -0700"
      },
      "message": "blkcg: drop BLKCG_STAT_{PRIV|POL|OFF} macros\n\nNow that all stat handling code lives in policy implementations,\nthere\u0027s no need to encode policy ID in cft-\u003eprivate.\n\n* Export blkcg_prfill_[rw]stat() from blkcg, remove\n  blkcg_print_[rw]stat(), and implement cfqg_print_[rw]stat() which\n  use hard-code BLKIO_POLICY_PROP.\n\n* Use cft-\u003eprivate for offset of the target field directly and drop\n  BLKCG_STAT_{PRIV|POL|OFF}().\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "d366e7ec41882791c970dfb7c67b737be8c3a174",
      "tree": "78d3c73d90276b797e1553c004272af869a30075",
      "parents": [
        "af133ceb261033eb43c03d161a991c3b772e8c56"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:44 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:44 2012 -0700"
      },
      "message": "blkcg: pass around pd-\u003epdata instead of pd itself in prfill functions\n\nNow that all conf and stat fields are moved into policy specific\nblkio_policy_data-\u003epdata areas, there\u0027s no reason to use\nblkio_policy_data itself in prfill functions.  Pass around @pd-\u003epdata\ninstead of @pd.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "af133ceb261033eb43c03d161a991c3b772e8c56",
      "tree": "fdc943f4f8c2c7e19af0d963d73647d3333aaa5c",
      "parents": [
        "3381cb8d2ef1523dbaeec99161d766c25f1e52d6"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:44 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:44 2012 -0700"
      },
      "message": "blkcg: move blkio_group_conf-\u003eiops and -\u003ebps to blk-throttle\n\nblkio_cgroup_conf-\u003eiops and -\u003ebps are owned by blk-throttle and has no\nreason to be defined in blkcg core.  Drop them and let conf setting\nfunctions directly manipulate throtl_grp-\u003ebps[] and -\u003eiops[].\n\nThis makes blkio_group_conf empty.  Drop it.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "3381cb8d2ef1523dbaeec99161d766c25f1e52d6",
      "tree": "b5592ee2a0f84e694282c947611971eb7735622d",
      "parents": [
        "8a3d26151f24e2a2ffa550890144c3d54d2edb15"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:44 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:44 2012 -0700"
      },
      "message": "blkcg: move blkio_group_conf-\u003eweight to cfq\n\nblkio_group_conf-\u003eweight is owned by cfq and has no reason to be\ndefined in blkcg core.  Replace it with cfq_group-\u003edev_weight and let\nconf setting functions directly set it.  If dev_weight is zero, the\ncfqg doesn\u0027t have device specific weight configured.\n\nAlso, rename BLKIO_WEIGHT_* constants to CFQ_WEIGHT_* and rename\nblkio_cgroup-\u003eweight to blkio_cgroup-\u003ecfq_weight.  We eventually want\nper-policy storage in blkio_cgroup but just mark the ownership of the\nfield for now.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "8a3d26151f24e2a2ffa550890144c3d54d2edb15",
      "tree": "b99f5cf8db0abc02e39e5c5107f8d4342f81effa",
      "parents": [
        "155fead9b6347ead90e0b0396cb108a6ba6126c6"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:44 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:44 2012 -0700"
      },
      "message": "blkcg: move blkio_group_stats_cpu and friends to blk-throttle.c\n\nblkio_group_stats_cpu is used only by blk-throtl and has no reason to\nbe defined in blkcg core.\n\n* Move blkio_group_stats_cpu to blk-throttle.c and rename it to\n  tg_stats_cpu.\n\n* blkg_policy_data-\u003estats_cpu is replaced with throtl_grp-\u003estats_cpu.\n  prfill functions updated accordingly.\n\n* All related macros / functions are renamed so that they have tg_\n  prefix and the unnecessary @pol arguments are dropped.\n\n* Per-cpu stats allocation code is also moved from blk-cgroup.c to\n  blk-throttle.c and gets simplified to only deal with\n  BLKIO_POLICY_THROTL.  percpu stat free is performed by the exit\n  method throtl_exit_blkio_group().\n\n* throtl_reset_group_stats() implemented for\n  blkio_reset_group_stats_fn method so that tg-\u003estats_cpu can be\n  reset.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "155fead9b6347ead90e0b0396cb108a6ba6126c6",
      "tree": "7e14bb87d942561aa5f44ac8a2d09d6e546c6ccb",
      "parents": [
        "9ade5ea4ce57d3596eaee6a57cd212a483674058"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:44 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:44 2012 -0700"
      },
      "message": "blkcg: move blkio_group_stats to cfq-iosched.c\n\nblkio_group_stats contains only fields used by cfq and has no reason\nto be defined in blkcg core.\n\n* Move blkio_group_stats to cfq-iosched.c and rename it to cfqg_stats.\n\n* blkg_policy_data-\u003estats is replaced with cfq_group-\u003estats.\n  blkg_prfill_[rw]stat() are updated to use offset against pd-\u003epdata\n  instead.\n\n* All related macros / functions are renamed so that they have cfqg_\n  prefix and the unnecessary @pol arguments are dropped.\n\n* All stat functions now take cfq_group * instead of blkio_group *.\n\n* lockdep assertion on queue lock dropped.  Elevator runs under queue\n  lock by default.  There isn\u0027t much to be gained by adding lockdep\n  assertions at stat function level.\n\n* cfqg_stats_reset() implemented for blkio_reset_group_stats_fn method\n  so that cfqg-\u003estats can be reset.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "9ade5ea4ce57d3596eaee6a57cd212a483674058",
      "tree": "cad2cc4ecb116f114cc73098b1704a47d82edd18",
      "parents": [
        "41b38b6d540f951c49315d8573e6f6195a6e736d"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:44 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:44 2012 -0700"
      },
      "message": "blkcg: add blkio_policy_ops operations for exit and stat reset\n\nAdd blkio_policy_ops-\u003eblkio_exit_group_fn() and\n-\u003eblkio_reset_group_stats_fn().  These will be used to further\nmodularize blkcg policy implementation.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "41b38b6d540f951c49315d8573e6f6195a6e736d",
      "tree": "e667cec0bba6e7678810ff0087c96547a21a45c7",
      "parents": [
        "629ed0b10209ffc4e1d439e5508d52d5e3a090b8"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:44 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:44 2012 -0700"
      },
      "message": "blkcg: cfq doesn\u0027t need per-cpu dispatch stats\n\nblkio_group_stats_cpu is used to count dispatch stats using per-cpu\ncounters.  This is used by both blk-throtl and cfq-iosched but the\nsharing is rather silly.\n\n* cfq-iosched doesn\u0027t need per-cpu dispatch stats.  cfq always updates\n  those stats while holding queue_lock.\n\n* blk-throtl needs per-cpu dispatch stats but only service_bytes and\n  serviced.  It doesn\u0027t make use of sectors.\n\nThis patch makes cfq add and use global stats for service_bytes,\nserviced and sectors, removes per-cpu sectors counter and moves\nper-cpu stat printing code to blk-throttle.c.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "629ed0b10209ffc4e1d439e5508d52d5e3a090b8",
      "tree": "69caa493e4ea0714aff247c8415c4fef7ebfe996",
      "parents": [
        "2ce4d50f9cfab40831eee5e51e950d5c4724994b"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:44 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:44 2012 -0700"
      },
      "message": "blkcg: move statistics update code to policies\n\nAs with conf/stats file handling code, there\u0027s no reason for stat\nupdate code to live in blkcg core with policies calling into update\nthem.  The current organization is both inflexible and complex.\n\nThis patch moves stat update code to specific policies.  All\nblkiocg_update_*_stats() functions which deal with BLKIO_POLICY_PROP\nstats are collapsed into their cfq_blkiocg_update_*_stats()\ncounterparts.  blkiocg_update_dispatch_stats() is used by both\npolicies and duplicated as throtl_update_dispatch_stats() and\ncfq_blkiocg_update_dispatch_stats().  This will be cleaned up later.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "60c2bc2d5a12369deef395cda41638d7e6b6bf19",
      "tree": "67fb6ace87a930215f800f0a96bb33f9773231c7",
      "parents": [
        "44ea53de46a8b01a65ae6217f47e00b516725190"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:43 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:43 2012 -0700"
      },
      "message": "blkcg: move conf/stat file handling code to policies\n\nblkcg conf/stat handling is convoluted in that details which belong to\nspecific policy implementations are all out in blkcg core and then\npolicies hook into core layer to access and manipulate confs and\nstats.  This sadly achieves both inflexibility (confs/stats can\u0027t be\nmodified without messing with blkcg core) and complexity (all the\ncall-ins and call-backs).\n\nThe previous patches restructured conf and stat handling code such\nthat they can be separated out.  This patch relocates the file\nhandling part.  All conf/stat file handling code which belongs to\nBLKIO_POLICY_PROP is moved to cfq-iosched.c and all\nBKLIO_POLICY_THROTL code to blk-throtl.c.\n\nThe move is verbatim except for blkio_update_group_{weight|bps|iops}()\ncallbacks which relays conf changes to policies.  The configuration\nsettings are handled in policies themselves so the relaying isn\u0027t\nnecessary.  Conf setting functions are modified to directly call\nper-policy update functions and the relaying mechanism is dropped.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "44ea53de46a8b01a65ae6217f47e00b516725190",
      "tree": "45ccff782042704818d0b3f96221c381209e4a2d",
      "parents": [
        "829fdb50004de78f1bd187e428d72edcd9721cb8"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:43 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:43 2012 -0700"
      },
      "message": "blkcg: implement blkio_policy_type-\u003ecftypes\n\nAdd blkiop-\u003ecftypes which is added and removed together with the\npolicy.  This will be used to move conf/stat handling to the policies.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "829fdb50004de78f1bd187e428d72edcd9721cb8",
      "tree": "96dbdb62c97e0b7a9a31a7af6d18a6c34e820528",
      "parents": [
        "726fa6945e6e5f0389bf47a790e1df734a67de54"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:43 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:43 2012 -0700"
      },
      "message": "blkcg: export conf/stat helpers to prepare for reorganization\n\nconf/stat handling is about to be moved to policy implementation from\nblkcg core.  Export conf/stat helpers from blkcg core so that\nblk-throttle and cfq-iosched can use them.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "3a8b31d396b296df4b8594429d86d415d3409432",
      "tree": "fe75761c55f91e558b5899cc284fa9b4134d8167",
      "parents": [
        "c4682aec9caaca1fcfd1dd4b59cef47af22cbdc6"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:43 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:43 2012 -0700"
      },
      "message": "blkcg: restructure blkio_group configruation setting\n\nAs part of userland interface restructuring, this patch updates\nper-blkio_group configuration setting.  Instead of funneling\neverything through a master function which has hard-coded cases for\neach config file it may handle, the common part is factored into\nblkg_conf_prep() and blkg_conf_finish() and different configuration\nsetters are implemented using the helpers.\n\nWhile this doesn\u0027t result in immediate LOC reduction, this enables\nfurther cleanups and more modular implementation.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "c4682aec9caaca1fcfd1dd4b59cef47af22cbdc6",
      "tree": "6e20981d877cf3dab29eb265f36edbd309f23761",
      "parents": [
        "627f29f48158c3088cc55a25d8650cae455ff63b"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:43 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:43 2012 -0700"
      },
      "message": "blkcg: restructure configuration printing\n\nSimilarly to the previous stat restructuring, this patch restructures\nconf printing code such that,\n\n* Conf printing uses the same helpers as stat.\n\n* Printing function doesn\u0027t require hardcoded switching on the config\n  being printed.  Note that this isn\u0027t complete yet for throttle\n  confs.  The next patch will convert setting for these confs and will\n  complete the transition.\n\n* Printing uses read_seq_string callback (other methods will be phased\n  out).\n\nNote that blkio_group_conf.iops[2] is changed to u64 so that they can\nbe manipulated with the same functions.  This is transitional and will\ngo away later.\n\nAfter this patch, per-device configurations - weight, bps and iops -\nuse __blkg_prfill_u64() for printing which uses white space as\ndelimiter instead of tab.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "d3d32e69fa368e131b25ee68806aa3fd3916cec1",
      "tree": "f6413e70f38cffb3b363fa831b5f868d90bb6c80",
      "parents": [
        "edcb0722c654947908388df660791abd41e6617c"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:42 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:42 2012 -0700"
      },
      "message": "blkcg: restructure statistics printing\n\nblkcg stats handling is a mess.  None of the stats has much to do with\nblkcg core but they are all implemented in blkcg core.  Code sharing\nis achieved by mixing common code with hard-coded cases for each stat\ncounter.\n\nThis patch restructures statistics printing such that\n\n* Common logic exists as helper functions and specific print functions\n  use the helpers to implement specific cases.\n\n* Printing functions serving multiple counters don\u0027t require hardcoded\n  switching on specific counters.\n\n* Printing uses read_seq_string callback (other methods will be phased\n  out).\n\nThis change enables further cleanups and relocating stats code to the\npolicy implementation it belongs to.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "edcb0722c654947908388df660791abd41e6617c",
      "tree": "8c44dd4517bd562b58216dd01fb5abc42cb74a95",
      "parents": [
        "2aa4a1523b40a065bc3a31e20097ea7a618ec3de"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:42 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:42 2012 -0700"
      },
      "message": "blkcg: introduce blkg_stat and blkg_rwstat\n\nblkcg uses u64_stats_sync to avoid reading wrong u64 statistic values\non 32bit archs and some stat counters have subtypes to distinguish\nread/writes and sync/async IOs.  The stat code paths are confusing and\ninvolve a lot of going back and forth between blkcg core and specific\npolicy implementations, and synchronization and subtype handling are\nopen coded in blkcg core.\n\nThis patch introduces struct blkg_stat and blkg_rwstat which, with\naccompanying operations, encapsulate stat updating and accessing with\nproper synchronization.\n\nblkg_stat is simple u64 counter with 64bit read-access protection.\nblkg_rwstat is the one with rw and [a]sync subcounters and takes @rw\nflags to distinguish IO subtypes (%REQ_WRITE and %REQ_SYNC) and\nreplaces stat_sub_type indexed arrays.\n\nAll counters in blkio_group_stats and blkio_group_stats_cpu are\nreplaced with either blkg_stat or blkg_rwstat along with all users.\n\nThis does add one u64_stats_sync per counter and increase stats_sync\noperations but they\u0027re empty/noops on 64bit archs and blkcg doesn\u0027t\nhave too many counters, especially with DEBUG_BLK_CGROUP off.\n\nWhile the currently resulting code isn\u0027t necessarily simpler at the\nmoment, this will enable further clean up of blkcg stats code.\n\n- BLKIO_STAT_{READ|WRITE|SYNC|ASYNC|TOTAL} renamed to\n  BLKG_RWSTAT_{READ|WRITE|SYNC|ASYNC|TOTAL}.\n\n- blkg_stat_add() replaces blkio_add_stat() and\n  blkio_check_and_dec_stat().  Note that BUG_ON() on underflow in the\n  latter function no longer exists.  It\u0027s *way* better to have\n  underflowed stat counters than oopsing.\n\n- blkio_group_stats-\u003edequeue is now a proper u64 stat counter instead\n  of ulong.\n\n- reset_stats() updated to clear each stat counters individually and\n  BLKG_STATS_DEBUG_CLEAR_{START|SIZE} are removed.\n\n- Some functions reconstruct rw flags from direction and sync\n  booleans.  This will be removed by future patches.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "2aa4a1523b40a065bc3a31e20097ea7a618ec3de",
      "tree": "b4fb9e7e593d539f70c61c2d7b39b0028edf08eb",
      "parents": [
        "aaec55a002a29bf940588dc03253099a4cd543bf"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:42 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:42 2012 -0700"
      },
      "message": "blkcg: BLKIO_STAT_CPU_SECTORS doesn\u0027t have subcounters\n\nBLKIO_STAT_CPU_SECTORS doesn\u0027t need read/write/sync/async subcounters\nand is counted by blkio_group_stats_cpu-\u003esectors; however, it still\nholds a member in blkio_group_stats_cpu-\u003estat_arr_cpu.\n\nRearrange stat_type_cpu and define BLKIO_STAT_CPU_ARR_NR and use it\nfor stat_arr_cpu[] size so that only SERVICE_BYTES and SERVICED have\nsubcounters.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "aaec55a002a29bf940588dc03253099a4cd543bf",
      "tree": "2fb146599db30c25abca72e52516d1c5f2c4e21e",
      "parents": [
        "959d851caa48829eb85cb85aa949fd6b4c5d5bc6"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:42 2012 -0700"
      },
      "committer": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Sun Apr 01 14:38:42 2012 -0700"
      },
      "message": "blkcg: remove unused @pol and @plid parameters\n\n@pol to blkg_to_pdata() and @plid to blkg_lookup_create() are no\nlonger necessary.  Drop them.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\n"
    },
    {
      "commit": "9a9e8a26da4c2c5ddc60999bdea957935fb22b6b",
      "tree": "5a42ef29c2c34174390e4ccf9a2924c0ade6f340",
      "parents": [
        "edf1b879e308d37b5b7c414476ab39f79650a253"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 19 15:10:56 2012 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 20 12:47:47 2012 +0100"
      },
      "message": "blkcg: add blkcg-\u003eid\n\nAdd 64bit unique id to blkcg.  This will be used by policies which\nwant blkcg identity test to tell whether the associated blkcg has\nchanged.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "edf1b879e308d37b5b7c414476ab39f79650a253",
      "tree": "fec2895e806eb357ba9e9ed960f8c247042d5383",
      "parents": [
        "c4c76a05382c7d05e0b911daa58a827399e9ba1a"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Thu Mar 08 10:54:00 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 20 12:45:37 2012 +0100"
      },
      "message": "blkcg: remove blkio_group-\u003estats_lock\n\nWith recent plug merge updates, all non-percpu stat updates happen\nunder queue_lock making stats_lock unnecessary to synchronize stat\nupdates.  The only synchronization necessary is stat reading, which\ncan be done using u64_stats_sync instead.\n\nThis patch removes blkio_group-\u003estats_lock and adds\nblkio_group_stats-\u003esyncp for reader synchronization.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "c4c76a05382c7d05e0b911daa58a827399e9ba1a",
      "tree": "e89f1edb9890a4b857f75dbdb4a0fb77d9aafa59",
      "parents": [
        "997a026c80c3cc05f82e589aced1f0011c17d376"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Thu Mar 08 10:53:59 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 20 12:45:37 2012 +0100"
      },
      "message": "blkcg: restructure blkio_get_stat()\n\nRestructure blkio_get_stat() to prepare for removal of stats_lock.\n\n* Define BLKIO_STAT_ARR_NR explicitly to denote which stats have\n  subtypes instead of using BLKIO_STAT_QUEUED.\n\n* Separate out stat acquisition and printing.  After this, there are\n  only two users of blkio_fill_stat().  Just open code it.\n\n* The code was mixing MAX_KEY_LEN and MAX_KEY_LEN - 1.  There\u0027s no\n  need to subtract one.  Use MAX_KEY_LEN consistently.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "997a026c80c3cc05f82e589aced1f0011c17d376",
      "tree": "905fe49970f8549663e1e70e77dd04811fd14c9c",
      "parents": [
        "5fe224d2d5fbf8f020b30d0ba69fed7856923752"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Thu Mar 08 10:53:58 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 20 12:45:37 2012 +0100"
      },
      "message": "blkcg: simplify stat reset\n\nblkiocg_reset_stats() implements stat reset for blkio.reset_stats\ncgroupfs file.  This feature is very unconventional and something\nwhich shouldn\u0027t have been merged.  It\u0027s only useful when there\u0027s only\none user or tool looking at the stats.  As soon as multiple users\nand/or tools are involved, it becomes useless as resetting disrupts\nother usages.  There are very good reasons why all other stats expect\nreaders to read values at the start and end of a period and subtract\nto determine delta over the period.\n\nThe implementation is rather complex - some fields shouldn\u0027t be\ncleared and it saves some fields, resets whole and restores for some\nreason.  Reset of percpu stats is also racy.  The comment points to\n64bit store atomicity for the reason but even without that stores for\nzero can simply race with other CPUs doing RMW and get clobbered.\n\nSimplify reset by\n\n* Clear selectively instead of resetting and restoring.\n\n* Grouping debug stat fields to be reset and using memset() over them.\n\n* Not caring about stats_lock.\n\n* Using memset() to reset percpu stats.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "5fe224d2d5fbf8f020b30d0ba69fed7856923752",
      "tree": "26941c40cd28c4f7070e8edab338d340afd2bc99",
      "parents": [
        "1cd9e039fc258f91fe38b97b3c622b13a3b8a795"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Thu Mar 08 10:53:57 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 20 12:45:37 2012 +0100"
      },
      "message": "blkcg: don\u0027t use percpu for merged stats\n\nWith recent plug merge updates, merged stats are no longer called for\nplug merges and now only updated while holding queue_lock.  As\nstats_lock is scheduled to be removed, there\u0027s no reason to use percpu\nfor merged stats.  Don\u0027t use percpu for merged stats.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "1cd9e039fc258f91fe38b97b3c622b13a3b8a795",
      "tree": "908f9747124b24ea4413025ab9294bd7d026b4f8",
      "parents": [
        "671058fb2a2aac4e70f01b316b06bc59b98bd138"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Thu Mar 08 10:53:56 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 20 12:45:37 2012 +0100"
      },
      "message": "blkcg: alloc per cpu stats from worker thread in a delayed manner\n\nCurrent per cpu stat allocation assumes GFP_KERNEL allocation flag. But in\nIO path there are times when we want GFP_NOIO semantics. As there is no\nway to pass the allocation flags to alloc_percpu(), this patch delays the\nallocation of stats using a worker thread.\n\nv2-\u003e tejun suggested following changes. Changed the patch accordingly.\n\t- move alloc_node location in structure\n\t- reduce the size of names of some of the fields\n\t- Reduce the scope of locking of alloc_list_lock\n\t- Simplified stat_alloc_fn() by allocating stats for all\n\t  policies in one go and then assigning these to a group.\n\nv3 -\u003e Andrew suggested to put some comments in the code. Also raised\n      concerns about trying to allocate infinitely in case of allocation\n      failure. I have changed the logic to sleep for 10ms before retrying.\n      That should take care of non-preemptible UP kernels.\n\nv4 -\u003e Tejun had more suggestions.\n\t- drop list_for_each_entry_all()\n\t- instead of msleep() use queue_delayed_work()\n\t- Some cleanups realted to more compact coding.\n\nv5-\u003e tejun suggested more cleanups leading to more compact code.\n\ntj: - Relocated pcpu_stats into blkio_stat_alloc_fn().\n    - Minor comment update.\n    - This also fixes suspicious RCU usage warning caused by invoking\n      cgroup_path() from blkg_alloc() without holding RCU read lock.\n      Now that blkg_alloc() doesn\u0027t require sleepable context, RCU\n      read lock from blkg_lookup_create() is maintained throughout\n      blkg_alloc().\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "4f85cb96d9d2fbbb7160db855a6beee1baced5e5",
      "tree": "5472bba04490da05fa6ca8f780431b37bd7375cb",
      "parents": [
        "852c788f8365062c8a383c5a93f7f7289977cb50"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:28 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:24 2012 +0100"
      },
      "message": "block: make block cgroup policies follow bio task association\n\nImplement bio_blkio_cgroup() which returns the blkcg associated with\nthe bio if exists or %current\u0027s blkcg, and use it in blk-throttle and\ncfq-iosched propio.  This makes both cgroup policies honor task\nassociation for the bio instead of always assuming %current.\n\nAs nobody is using bio_set_task() yet, this doesn\u0027t introduce any\nbehavior change.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "c875f4d0250a1f070fa26087a73bdd8f54c48100",
      "tree": "4ed2bae2fc48e54ac712d28eaaae8217c8064c1d",
      "parents": [
        "9f13ef678efd977487fc0c2e489f17c9a8c67a3e"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:22 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:24 2012 +0100"
      },
      "message": "blkcg: drop unnecessary RCU locking\n\nNow that blkg additions / removals are always done under both q and\nblkcg locks, the only places RCU locking is necessary are\nblkg_lookup[_create]() for lookup w/o blkcg lock.  This patch drops\nunncessary RCU locking replacing it with plain blkcg locking as\nnecessary.\n\n* blkiocg_pre_destroy() already perform proper locking and don\u0027t need\n  RCU.  Dropped.\n\n* blkio_read_blkg_stats() now uses blkcg-\u003elock instead of RCU read\n  lock.  This isn\u0027t a hot path.\n\n* Now unnecessary synchronize_rcu() from queue exit paths removed.\n  This makes q-\u003enr_blkgs unnecessary.  Dropped.\n\n* RCU annotation on blkg-\u003eq removed.\n\n-v2: Vivek pointed out that blkg_lookup_create() still needs to be\n     called under rcu_read_lock().  Updated.\n\n-v3: After the update, stats_lock locking in blkio_read_blkg_stats()\n     shouldn\u0027t be using _irq variant as it otherwise ends up enabling\n     irq while blkcg-\u003elock is locked.  Fixed.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "9f13ef678efd977487fc0c2e489f17c9a8c67a3e",
      "tree": "e58a2dd153ad24b2ea173d5dfb575c507e1f7589",
      "parents": [
        "e8989fae38d9831c72b20375a206a919ca468c52"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:21 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:24 2012 +0100"
      },
      "message": "blkcg: use double locking instead of RCU for blkg synchronization\n\nblkgs are chained from both blkcgs and request_queues and thus\nsubjected to two locks - blkcg-\u003elock and q-\u003equeue_lock.  As both blkcg\nand q can go away anytime, locking during removal is tricky.  It\u0027s\ncurrently solved by wrapping removal inside RCU, which makes the\nsynchronization complex.  There are three locks to worry about - the\nouter RCU, q lock and blkcg lock, and it leads to nasty subtle\ncomplications like conditional synchronize_rcu() on queue exit paths.\n\nFor all other paths, blkcg lock is naturally nested inside q lock and\nthe only exception is blkcg removal path, which is a very cold path\nand can be implemented as clumsy but conceptually-simple reverse\ndouble lock dancing.\n\nThis patch updates blkg removal path such that blkgs are removed while\nholding both q and blkcg locks, which is trivial for request queue\nexit path - blkg_destroy_all().  The blkcg removal path,\nblkiocg_pre_destroy(), implements reverse double lock dancing\nessentially identical to ioc_release_fn().\n\nThis simplifies blkg locking - no half-dead blkgs to worry about.  Now\nunnecessary RCU annotations will be removed by the next patch.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "e8989fae38d9831c72b20375a206a919ca468c52",
      "tree": "2eeb1320e526cd0ba187465c0e6e19799dc1b956",
      "parents": [
        "03aa264ac15637b6f98374270bcdf31400965505"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:20 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:23 2012 +0100"
      },
      "message": "blkcg: unify blkg\u0027s for blkcg policies\n\nCurrently, blkg is per cgroup-queue-policy combination.  This is\nunnatural and leads to various convolutions in partially used\nduplicate fields in blkg, config / stat access, and general management\nof blkgs.\n\nThis patch make blkg\u0027s per cgroup-queue and let them serve all\npolicies.  blkgs are now created and destroyed by blkcg core proper.\nThis will allow further consolidation of common management logic into\nblkcg core and API with better defined semantics and layering.\n\nAs a transitional step to untangle blkg management, elvswitch and\npolicy [de]registration, all blkgs except the root blkg are being shot\ndown during elvswitch and bypass.  This patch adds blkg_root_update()\nto update root blkg in place on policy change.  This is hacky and racy\nbut should be good enough as interim step until we get locking\nsimplified and switch over to proper in-place update for all blkgs.\n\n-v2: Root blkgs need to be updated on elvswitch too and blkg_alloc()\n     comment wasn\u0027t updated according to the function change.  Fixed.\n     Both pointed out by Vivek.\n\n-v3: v2 updated blkg_destroy_all() to invoke update_root_blkg_pd() for\n     all policies.  This freed root pd during elvswitch before the\n     last queue finished exiting and led to oops.  Directly invoke\n     update_root_blkg_pd() only on BLKIO_POLICY_PROP from\n     cfq_exit_queue().  This also is closer to what will be done with\n     proper in-place blkg update.  Reported by Vivek.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "03aa264ac15637b6f98374270bcdf31400965505",
      "tree": "6fa9ca54d3f775fba19123790f6655158034a1d8",
      "parents": [
        "4eef3049986e8397d5003916aed8cad6567a5e02"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:19 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:23 2012 +0100"
      },
      "message": "blkcg: let blkcg core manage per-queue blkg list and counter\n\nWith the previous patch to move blkg list heads and counters to\nrequest_queue and blkg, logic to manage them in both policies are\nalmost identical and can be moved to blkcg core.\n\nThis patch moves blkg link logic into blkg_lookup_create(), implements\ncommon blkg unlink code in blkg_destroy(), and updates\nblkg_destory_all() so that it\u0027s policy specific and can skip root\ngroup.  The updated blkg_destroy_all() is now used to both clear queue\nfor bypassing and elv switching, and release all blkgs on q exit.\n\nThis patch introduces a race window where policy [de]registration may\nrace against queue blkg clearing.  This can only be a problem on cfq\nunload and shouldn\u0027t be a real problem in practice (and we have many\nother places where this race already exists).  Future patches will\nremove these unlikely races.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "4eef3049986e8397d5003916aed8cad6567a5e02",
      "tree": "5e36431986907b9fa728a6fbeb819a2738a64c82",
      "parents": [
        "c1768268f9424410761da57ea71107acae7b03cc"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:18 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:23 2012 +0100"
      },
      "message": "blkcg: move per-queue blkg list heads and counters to queue and blkg\n\nCurrently, specific policy implementations are responsible for\nmaintaining list and number of blkgs.  This duplicates code\nunnecessarily, and hinders factoring common code and providing blkcg\nAPI with better defined semantics.\n\nAfter this patch, request_queue hosts list heads and counters and blkg\nhas list nodes for both policies.  This patch only relocates the\nnecessary fields and the next patch will actually move management code\ninto blkcg core.\n\nNote that request_queue-\u003eblkg_list[] and -\u003enr_blkgs[] are hardcoded to\nhave 2 elements.  This is to avoid include dependency and will be\nremoved by the next patch.\n\nThis patch doesn\u0027t introduce any behavior change.\n\n-v2: Now unnecessary conditional on CONFIG_BLK_CGROUP_MODULE removed\n     as pointed out by Vivek.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "c1768268f9424410761da57ea71107acae7b03cc",
      "tree": "be6a534b1a15ab9df9f23e585b039776c5a5e498",
      "parents": [
        "549d3aa872cd1aec1ee540fd93afd9611faa0def"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:17 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:23 2012 +0100"
      },
      "message": "blkcg: don\u0027t use blkg-\u003eplid in stat related functions\n\nblkg is scheduled to be unified for all policies and thus there won\u0027t\nbe one-to-one mapping from blkg to policy.  Update stat related\nfunctions to take explicit @pol or @plid arguments and not use\nblkg-\u003eplid.\n\nThis is painful for now but most of specific stat interface functions\nwill be replaced with a handful of generic helpers.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "549d3aa872cd1aec1ee540fd93afd9611faa0def",
      "tree": "27c3703d3448dc0be9f58b5f01224ae901422a32",
      "parents": [
        "1adaf3dde37a8b9b59ea59c5f58fed7761178383"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:16 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:23 2012 +0100"
      },
      "message": "blkcg: make blkg-\u003epd an array and move configuration and stats into it\n\nTo prepare for unifying blkgs for different policies, make blkg-\u003epd an\narray with BLKIO_NR_POLICIES elements and move blkg-\u003econf, -\u003estats,\nand -\u003estats_cpu into blkg_policy_data.\n\nThis patch doesn\u0027t introduce any functional difference.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "1adaf3dde37a8b9b59ea59c5f58fed7761178383",
      "tree": "e4a46485b1bf0370aa41a5b9a8f138fba34c9d23",
      "parents": [
        "0381411e4b1a52cee134eb73750e5e3cc1155d09"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:15 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:23 2012 +0100"
      },
      "message": "blkcg: move refcnt to blkcg core\n\nCurrently, blkcg policy implementations manage blkg refcnt duplicating\nmostly identical code in both policies.  This patch moves refcnt to\nblkg and let blkcg core handle refcnt and freeing of blkgs.\n\n* cfq blkgs now also get freed via RCU.\n\n* cfq blkgs lose RB_EMPTY_ROOT() sanity check on blkg free.  If\n  necessary, we can add blkio_exit_group_fn() to resurrect this.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "0381411e4b1a52cee134eb73750e5e3cc1155d09",
      "tree": "32aa1d0b8a2ca8277e60e8b78dd731d193440924",
      "parents": [
        "923adde1be1df57cebd80c563058e503376645e8"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:14 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:23 2012 +0100"
      },
      "message": "blkcg: let blkcg core handle policy private data allocation\n\nCurrently, blkg\u0027s are embedded in private data blkcg policy private\ndata structure and thus allocated and freed by policies.  This leads\nto duplicate codes in policies, hinders implementing common part in\nblkcg core with strong semantics, and forces duplicate blkg\u0027s for the\nsame cgroup-q association.\n\nThis patch introduces struct blkg_policy_data which is a separate data\nstructure chained from blkg.  Policies specifies the amount of private\ndata it needs in its blkio_policy_type-\u003epdata_size and blkcg core\ntakes care of allocating them along with blkg which can be accessed\nusing blkg_to_pdata().  blkg can be determined from pdata using\npdata_to_blkg().  blkio_alloc_group_fn() method is accordingly updated\nto blkio_init_group_fn().\n\nFor consistency, tg_of_blkg() and cfqg_of_blkg() are replaced with\nblkg_to_tg() and blkg_to_cfqg() respectively, and functions to map in\nthe reverse direction are added.\n\nExcept that policy specific data now lives in a separate data\nstructure from blkg, this patch doesn\u0027t introduce any functional\ndifference.\n\nThis will be used to unify blkg\u0027s for different policies.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "5efd611351d1a847c72d74fb12ff4bd187c0cb2c",
      "tree": "bac28206d088426ab872eea98155cc100bd8d9b1",
      "parents": [
        "7ee9c5620504906e98451dc9a1945b2b9e892cb8"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:12 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:23 2012 +0100"
      },
      "message": "blkcg: add blkcg_{init|drain|exit}_queue()\n\nCurrently block core calls directly into blk-throttle for init, drain\nand exit.  This patch adds blkcg_{init|drain|exit}_queue() which wraps\nthe blk-throttle functions.  This is to give more control and\nvisiblity to blkcg core layer for proper layering.  Further patches\nwill add logic common to blkcg policies to the functions.\n\nWhile at it, collapse blk_throtl_release() into blk_throtl_exit().\nThere\u0027s no reason to keep them separate.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "7ee9c5620504906e98451dc9a1945b2b9e892cb8",
      "tree": "1daf4d9fc8d03ebbc88ceedb7abeec46d8c71df3",
      "parents": [
        "92616b5b3a7c7fa8148df82e7ff6183056f2bfc8"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:11 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:23 2012 +0100"
      },
      "message": "blkcg: let blkio_group point to blkio_cgroup directly\n\nCurrently, blkg points to the associated blkcg via its css_id.  This\nunnecessarily complicates dereferencing blkcg.  Let blkg hold a\nreference to the associated blkcg and point directly to it and disable\ncss_id on blkio_subsys.\n\nThis change requires splitting blkiocg_destroy() into\nblkiocg_pre_destroy() and blkiocg_destroy() so that all blkg\u0027s can be\ndestroyed and all the blkcg references held by them dropped during\ncgroup removal.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "7a4dd281ec66224f802093962d1d903d86b09560",
      "tree": "c38c5c40464d4d7eb429cc14348a435176832ef2",
      "parents": [
        "4bfd482e73b30284cb21e10834ce729fa81aa256"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:09 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:22 2012 +0100"
      },
      "message": "blkcg: kill the mind-bending blkg-\u003edev\n\nblkg-\u003edev is dev_t recording the device number of the block device for\nthe associated request_queue.  It is used to identify the associated\nblock device when printing out configuration or stats.\n\nThis is redundant to begin with.  A blkg is an association between a\ncgroup and a request_queue and it of course is possible to reach\nrequest_queue from blkg and synchronization conventions are in place\nfor safe q dereferencing, so this shouldn\u0027t be necessary from the\nbeginning.  Furthermore, it\u0027s initialized by sscanf()ing the device\nname of backing_dev_info.  The mind boggles.\n\nAnyways, if blkg is visible under rcu lock, we *know* that the\nassociated request_queue hasn\u0027t gone away yet and its bdi is\nregistered and alive - blkg can\u0027t be created for request_queue which\nhasn\u0027t been fully initialized and it can\u0027t go away before blkg is\nremoved.\n\nLet stat and conf read functions get device name from\nblkg-\u003eq-\u003ebacking_dev_info.dev and pass it down to printing functions\nand remove blkg-\u003edev.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "4bfd482e73b30284cb21e10834ce729fa81aa256",
      "tree": "2c39e09592113946e3545013199b0e00a21f60f2",
      "parents": [
        "e56da7e287967667474a58c4f60c286279e3f487"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:08 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:22 2012 +0100"
      },
      "message": "blkcg: kill blkio_policy_node\n\nNow that blkcg configuration lives in blkg\u0027s, blkio_policy_node is no\nlonger necessary.  Kill it.\n\nblkio_policy_parse_and_set() now fails if invoked for missing device\nand functions to print out configurations are updated to print from\nblkg\u0027s.\n\ncftype_blkg_same_policy() is dropped along with other policy functions\nfor consistency.  Its one line is open coded in the only user -\nblkio_read_blkg_stats().\n\n-v2: Update to reflect the retry-on-bypass logic change of the\n     previous patch.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "e56da7e287967667474a58c4f60c286279e3f487",
      "tree": "4ce64581888f287a25b4abdc21fc641210351612",
      "parents": [
        "cd1604fab4f95f7cfc227d3955fd7ae14da61f38"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:07 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:22 2012 +0100"
      },
      "message": "blkcg: don\u0027t allow or retain configuration of missing devices\n\nblkcg is very peculiar in that it allows setting and remembering\nconfigurations for non-existent devices by maintaining separate data\nstructures for configuration.\n\nThis behavior is completely out of the usual norms and outright\nconfusing; furthermore, it uses dev_t number to match the\nconfiguration to devices, which is unpredictable to begin with and\nbecomes completely unuseable if EXT_DEVT is fully used.\n\nIt is wholely unnecessary - we already have fully functional userland\nmechanism to program devices being hotplugged which has full access to\ndevice identification, connection topology and filesystem information.\n\nAdd a new struct blkio_group_conf which contains all blkcg\nconfigurations to blkio_group and let blkio_group, which can be\ncreated iff the associated device exists and is removed when the\nassociated device goes away, carry all configurations.\n\nNote that, after this patch, all newly created blkg\u0027s will always have\nthe default configuration (unlimited for throttling and blkcg\u0027s weight\nfor propio).\n\nThis patch makes blkio_policy_node meaningless but doesn\u0027t remove it.\nThe next patch will.\n\n-v2: Updated to retry after short sleep if blkg lookup/creation failed\n     due to the queue being temporarily bypassed as indicated by\n     -EBUSY return.  Pointed out by Vivek.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nCc: Kay Sievers \u003ckay.sievers@vrfy.org\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "cd1604fab4f95f7cfc227d3955fd7ae14da61f38",
      "tree": "021881faedc1c2468730f9f54d364083e70dce76",
      "parents": [
        "f51b802c17e2a21926b29911493f5e7ddf6eee87"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:06 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:22 2012 +0100"
      },
      "message": "blkcg: factor out blkio_group creation\n\nCurrently both blk-throttle and cfq-iosched implement their own\nblkio_group creation code in throtl_get_tg() and cfq_get_cfqg().  This\npatch factors out the common code into blkg_lookup_create(), which\nreturns ERR_PTR value so that transitional failures due to queue\nbypass can be distinguished from other failures.\n\n* New plkio_policy_ops methods blkio_alloc_group_fn() and\n  blkio_link_group_fn added.  Both are transitional and will be\n  removed once the blkg management code is fully moved into\n  blk-cgroup.c.\n\n* blkio_alloc_group_fn() allocates policy-specific blkg which is\n  usually a larger data structure with blkg as the first entry and\n  intiailizes it.  Note that initialization of blkg proper, including\n  percpu stats, is responsibility of blk-cgroup proper.\n\n  Note that default config (weight, bps...) initialization is done\n  from this method; otherwise, we end up violating locking order\n  between blkcg and q locks via blkcg_get_CONF() functions.\n\n* blkio_link_group_fn() is called under queue_lock and responsible for\n  linking the blkg to the queue.  blkcg side is handled by blk-cgroup\n  proper.\n\n* The common blkg creation function is named blkg_lookup_create() and\n  blkiocg_lookup_group() is renamed to blkg_lookup() for consistency.\n  Also, throtl / cfq related functions are similarly [re]named for\n  consistency.\n\nThis simplifies blkcg policy implementations and enables further\ncleanup.\n\n-v2: Vivek noticed that blkg_lookup_create() incorrectly tested\n     blk_queue_dead() instead of blk_queue_bypass() leading a user of\n     the function ending up creating a new blkg on bypassing queue.\n     This is a bug introduced while relocating bypass patches before\n     this one.  Fixed.\n\n-v3: ERR_PTR patch folded into this one.  @for_root added to\n     blkg_lookup_create() to allow creating root group on a bypassed\n     queue during elevator switch.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "035d10b2fa7e5f7e9bf9465dbc39c35affd5ac32",
      "tree": "6a712eb1b505e8163d28f8709980e581a08b572c",
      "parents": [
        "ca32aefc7f2539ed88d42763330d54ee3e61769a"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:04 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:22 2012 +0100"
      },
      "message": "blkcg: add blkio_policy[] array and allow one policy per policy ID\n\nBlock cgroup policies are maintained in a linked list and,\ntheoretically, multiple policies sharing the same policy ID are\nallowed.\n\nThis patch temporarily restricts one policy per plid and adds\nblkio_policy[] array which indexes registered policy types by plid.\nBoth the restriction and blkio_policy[] array are transitional and\nwill be removed once API cleanup is complete.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "ca32aefc7f2539ed88d42763330d54ee3e61769a",
      "tree": "791d2ac1c11b738ce34629653090b6e971fc11b5",
      "parents": [
        "0a5a7d0e32be6643b881f0e7cd9d0d06fadde27a"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:03 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:22 2012 +0100"
      },
      "message": "blkcg: use q and plid instead of opaque void * for blkio_group association\n\nblkgio_group is association between a block cgroup and a queue for a\ngiven policy.  Using opaque void * for association makes things\nconfusing and hinders factoring of common code.  Use request_queue *\nand, if necessary, policy id instead.\n\nThis will help block cgroup API cleanup.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "72e06c255181537d0b3e1f657a9ed81655d745b1",
      "tree": "eb656df2ad23a7709b4e9fe58f1dabdc32be9ae9",
      "parents": [
        "6ecf23afab13c39d3bb0e2d826d0984b0dd53733"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:15:00 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:22 2012 +0100"
      },
      "message": "blkcg: shoot down blkio_groups on elevator switch\n\nElevator switch may involve changes to blkcg policies.  Implement\nshoot down of blkio_groups.\n\nCombined with the previous bypass updates, the end goal is updating\nblkcg core such that it can ensure that blkcg\u0027s being affected become\nquiescent and don\u0027t have any per-blkg data hanging around before\ncommencing any policy updates.  Until queues are made aware of the\npolicies that applies to them, as an interim step, all per-policy blkg\ndata will be shot down.\n\n* blk-throtl doesn\u0027t need this change as it can\u0027t be disabled for a\n  live queue; however, update it anyway as the scheduled blkg\n  unification requires this behavior change.  This means that\n  blk-throtl configuration will be unnecessarily lost over elevator\n  switch.  This oddity will be removed after blkcg learns to associate\n  individual policies with request_queues.\n\n* blk-throtl dosen\u0027t shoot down root_tg.  This is to ease transition.\n  Unified blkg will always have persistent root group and not shooting\n  down root_tg for now eases transition to that point by avoiding\n  having to update td-\u003eroot_tg and is safe as blk-throtl can never be\n  disabled\n\n-v2: Vivek pointed out that group list is not guaranteed to be empty\n     on return from clear function if it raced cgroup removal and\n     lost.  Fix it by waiting a bit and retrying.  This kludge will\n     soon be removed once locking is updated such that blkg is never\n     in limbo state between blkcg and request_queue locks.\n\n     blk-throtl no longer shoots down root_tg to avoid breaking\n     td-\u003eroot_tg.\n\n     Also, Nest queue_lock inside blkio_list_lock not the other way\n     around to avoid introduce possible deadlock via blkcg lock.\n\n-v3: blkcg_clear_queue() repositioned and renamed to\n     blkg_destroy_all() to increase consistency with later changes.\n     cfq_clear_queue() updated to check q-\u003eelevator before\n     dereferencing it to avoid NULL dereference on not fully\n     initialized queues (used by later change).\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "32e380aedc3de454c06ce1c254fe3bea35a676e1",
      "tree": "ae48ced36af22f020451cb05ecca835ff561dc9d",
      "parents": [
        "b855b04a0b2213dbc1b59cf936056726e7ed97ad"
      ],
      "author": {
        "name": "Tejun Heo",
        "email": "tj@kernel.org",
        "time": "Mon Mar 05 13:14:54 2012 -0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Tue Mar 06 21:27:21 2012 +0100"
      },
      "message": "blkcg: make CONFIG_BLK_CGROUP bool\n\nBlock cgroup core can be built as module; however, it isn\u0027t too useful\nas blk-throttle can only be built-in and cfq-iosched is usually the\ndefault built-in scheduler.  Scheduled blkcg cleanup requires calling\ninto blkcg from block core.  To simplify that, disallow building blkcg\nas module by making CONFIG_BLK_CGROUP bool.\n\nIf building blkcg core as module really matters, which I doubt, we can\nrevisit it after blkcg API cleanup.\n\n-v2: Vivek pointed out that IOSCHED_CFQ was incorrectly updated to\n     depend on BLK_CGROUP.  Fixed.\n\nSigned-off-by: Tejun Heo \u003ctj@kernel.org\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "e890413af4c2dfebf5432ef30cc70cb11dad3213",
      "tree": "26649bfe90854128ce87b57ef8aa3ca985454e78",
      "parents": [
        "3bcfeaf93f44112053e1c36aa681d9efc1185ddc"
      ],
      "author": {
        "name": "Jie Liu",
        "email": "jeff.liu@oracle.com",
        "time": "Mon Oct 24 16:08:38 2011 +0200"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "axboe@kernel.dk",
        "time": "Mon Oct 24 16:08:38 2011 +0200"
      },
      "message": "block: fix a typo in the blk-cgroup.h file\n\nbyptes -\u003e bytes.\n\nSigned-off-by: Jie Liu \u003cjeff.liu@oracle.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n"
    },
    {
      "commit": "317389a7739675aa990b7e0d750a7c435f1d25d7",
      "tree": "c24b7bb45d03233d76405dab4f9406c05c44eafa",
      "parents": [
        "2abae55f5a41d29f21b5b259c33d218c950d5c90"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Mon May 23 10:02:19 2011 +0200"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jaxboe@fusionio.com",
        "time": "Mon May 23 10:02:19 2011 +0200"
      },
      "message": "cfq-iosched: Make IO merge related stats per cpu\n\nMake BLKIO_STAT_MERGED per cpu hence gettring rid of need of taking\nblkg-\u003estats_lock.\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjaxboe@fusionio.com\u003e\n"
    },
    {
      "commit": "575969a0dd3fe65c6556bcb8f87c42303326ea55",
      "tree": "0db18fa173b20076e03b5b9c4be4c31c56baa438",
      "parents": [
        "5624a4e445e2ec27582984b068d7bf7f127cee10"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Thu May 19 15:38:29 2011 -0400"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jaxboe@fusionio.com",
        "time": "Fri May 20 20:34:53 2011 +0200"
      },
      "message": "blk-cgroup: Make 64bit per cpu stats safe on 32bit arch\n\nSome of the stats are 64bit and updation will be non atomic on 32bit\narchitecture. Use sequence counters on 32bit arch to make reading\nof stats safe.\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjaxboe@fusionio.com\u003e\n"
    },
    {
      "commit": "5624a4e445e2ec27582984b068d7bf7f127cee10",
      "tree": "0827c83c6e5f5fa83bd0dadc1bc395c0f0657dae",
      "parents": [
        "4843c69d496a8d2e4caab6182fe016b9a79136e0"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Thu May 19 15:38:28 2011 -0400"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jaxboe@fusionio.com",
        "time": "Fri May 20 20:34:52 2011 +0200"
      },
      "message": "blk-throttle: Make dispatch stats per cpu\n\nCurrently we take blkg_stat lock for even updating the stats. So even if\na group has no throttling rules (common case for root group), we end\nup taking blkg_lock, for updating the stats.\n\nMake dispatch stats per cpu so that these can be updated without taking\nblkg lock.\n\nIf cpu goes offline, these stats simply disappear. No protection has\nbeen provided for that yet. Do we really need anything for that?\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjaxboe@fusionio.com\u003e\n"
    },
    {
      "commit": "a23e68695593d00b35a6cddf8e9c9ec03505ecb9",
      "tree": "954a92fb07408e4b7483881f09d2afc91002bc00",
      "parents": [
        "a29a171e7c46c60842b85729280e2f5690372683"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Thu May 19 15:38:20 2011 -0400"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jaxboe@fusionio.com",
        "time": "Fri May 20 20:34:52 2011 +0200"
      },
      "message": "blk-cgroup: move some fields of unaccounted_time file under right config option\n\ncgroup unaccounted_time file is created only if CONFIG_DEBUG_BLK_CGROUP\u003dy.\nthere are some fields which are out side this config option. Fix that.\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjaxboe@fusionio.com\u003e\n"
    },
    {
      "commit": "70087dc38cc77ca8f46059564c00338777734762",
      "tree": "2ffd5885a12acb44d90d3c3c1a578387bad94a32",
      "parents": [
        "02e352287a40bd456eb78df705bf888bc3161d3f"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Mon May 16 15:24:08 2011 +0200"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jaxboe@fusionio.com",
        "time": "Mon May 16 15:24:08 2011 +0200"
      },
      "message": "blk-throttle: Use task_subsys_state() to determine a task\u0027s blkio_cgroup\n\nCurrentlly we first map the task to cgroup and then cgroup to\nblkio_cgroup. There is a more direct way to get to blkio_cgroup\nfrom task using task_subsys_state(). Use that.\n\nThe real reason for the fix is that it also avoids a race in generic\ncgroup code. During remount/umount rebind_subsystems() is called and\nit can do following with and rcu protection.\n\ncgrp-\u003esubsys[i] \u003d NULL;\n\nThat means if somebody got hold of cgroup under rcu and then it tried\nto do cgroup-\u003esubsys[] to get to blkio_cgroup, it would get NULL which\nis wrong. I was running into this race condition with ltp running on a\nupstream derived kernel and that lead to crash.\n\nSo ideally we should also fix cgroup generic code to wait for rcu\ngrace period before setting pointer to NULL. Li Zefan is not very keen\non introducing synchronize_wait() as he thinks it will slow\ndown moun/remount/umount operations.\n\nSo for the time being atleast fix the kernel crash by taking a more\ndirect route to blkio_cgroup.\n\nOne tester had reported a crash while running LTP on a derived kernel\nand with this fix crash is no more seen while the test has been\nrunning for over 6 days.\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nReviewed-by: Li Zefan \u003clizf@cn.fujitsu.com\u003e\nSigned-off-by: Jens Axboe \u003cjaxboe@fusionio.com\u003e\n"
    },
    {
      "commit": "167400d34070ebbc408dc0f447c4ddb4bf837360",
      "tree": "19100b0511a7e3e18f6f61d90a5fe5f1c40f59c4",
      "parents": [
        "1f940bdfc0d03265d178d9dfd840d854819f797d"
      ],
      "author": {
        "name": "Justin TerAvest",
        "email": "teravest@google.com",
        "time": "Sat Mar 12 16:54:00 2011 +0100"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jaxboe@fusionio.com",
        "time": "Sat Mar 12 16:54:00 2011 +0100"
      },
      "message": "blk-cgroup: Add unaccounted time to timeslice_used.\n\nThere are two kind of times that tasks are not charged for: the first\nseek and the extra time slice used over the allocated timeslice. Both\nof these exported as a new unaccounted_time stat.\n\nI think it would be good to have this reported in \u0027time\u0027 as well, but\nthat is probably a separate discussion.\n\nSigned-off-by: Justin TerAvest \u003cteravest@google.com\u003e\nSigned-off-by: Jens Axboe \u003cjaxboe@fusionio.com\u003e\n"
    },
    {
      "commit": "df457f845e5449be2e7d96668791f789b3770ac7",
      "tree": "5279d8ad1379ab890a90453d5018bb473c90d7d5",
      "parents": [
        "df677140281beb608f6748c341af7612f7bfe7a0"
      ],
      "author": {
        "name": "Justin TerAvest",
        "email": "teravest@google.com",
        "time": "Tue Mar 08 19:45:00 2011 +0100"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jaxboe@fusionio.com",
        "time": "Tue Mar 08 19:45:00 2011 +0100"
      },
      "message": "blk-cgroup: Lower minimum weight from 100 to 10.\n\nWe\u0027ve found that we still get good, useful isolation at weights this\nlow. I\u0027d like to adjust the minimum so that any other changes can take\nthese values into account.\n\nSigned-off-by: Justin TerAvest \u003cteravest@google.com\u003e\nAcked-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjaxboe@fusionio.com\u003e\n"
    },
    {
      "commit": "9355aede5a3c4975e0ba8bbfe2b9d1fd73308916",
      "tree": "73db212009de0e60d71d343b737d6a90449b06b8",
      "parents": [
        "5e901a2b95db709c5e40599ff4df6029be1e2a12"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Fri Oct 01 21:16:41 2010 +0200"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jaxboe@fusionio.com",
        "time": "Fri Oct 01 21:16:41 2010 +0200"
      },
      "message": "blkio-throttle: limit max iops value to UINT_MAX\n\n- Limit max iops value to UINT_MAX and return error to user if value is more\n  than that instead of accepting bigger values and truncating implicitly.\n\nSigned-off-by: Jens Axboe \u003cjaxboe@fusionio.com\u003e\n"
    },
    {
      "commit": "fe0714377ee2ca161bf2afb7773e22f15f1786d4",
      "tree": "09f5e8686d741d012333c92251b8cc66793ef916",
      "parents": [
        "02977e4af7ed3b478c505e50491ffdf3e1314cf4"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Fri Oct 01 14:49:49 2010 +0200"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jaxboe@fusionio.com",
        "time": "Fri Oct 01 14:49:49 2010 +0200"
      },
      "message": "blkio: Recalculate the throttled bio dispatch time upon throttle limit change\n\no Currently any cgroup throttle limit changes are processed asynchronousy and\n  the change does not take affect till a new bio is dispatched from same group.\n\no It might happen that a user sets a redicuously low limit on throttling.\n  Say 1 bytes per second on reads. In such cases simple operations like mount\n  a disk can wait for a very long time.\n\no Once bio is throttled, there is no easy way to come out of that wait even if\n  user increases the read limit later.\n\no This patch fixes it. Now if a user changes the cgroup limits, we recalculate\n  the bio dispatch time according to new limits.\n\no Can\u0027t take queueu lock under blkcg_lock, hence after the change I wake\n  up the dispatch thread again which recalculates the time. So there are some\n  variables being synchronized across two threads without lock and I had to\n  make use of barriers. Hoping I have used barriers correctly. Any review of\n  memory barrier code especially will help.\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjaxboe@fusionio.com\u003e\n"
    },
    {
      "commit": "7702e8f45b0a3bb262b9366c60beb5445758d94c",
      "tree": "bd61754827def804fe5a1f790f3eb303154df63d",
      "parents": [
        "e43473b7f223ec866f7db273697e76c337c390f9"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Wed Sep 15 17:06:36 2010 -0400"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jaxboe@fusionio.com",
        "time": "Thu Sep 16 08:42:58 2010 +0200"
      },
      "message": "blk-cgroup: cgroup changes for IOPS limit support\n\no cgroup changes for IOPS throttling rules.\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjaxboe@fusionio.com\u003e\n"
    },
    {
      "commit": "4c9eefa16c6f124ffcc736cb719b24ea27f85017",
      "tree": "0fc333553f66b72c3eb1bd532e45040d90e68f1f",
      "parents": [
        "062a644d6121d5e2f51c0b2ca0cbc5155ebf845b"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Wed Sep 15 17:06:34 2010 -0400"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jaxboe@fusionio.com",
        "time": "Thu Sep 16 08:42:12 2010 +0200"
      },
      "message": "blk-cgroup: Introduce cgroup changes for throttling policy\n\no cgroup chagnes for throttle policy.\n\no Introduces READ and WRITE bytes per second throttling rules.\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjaxboe@fusionio.com\u003e\n"
    },
    {
      "commit": "062a644d6121d5e2f51c0b2ca0cbc5155ebf845b",
      "tree": "250626a8ee11efa8e598692904e12ac26c29cab5",
      "parents": [
        "af41d7bd9b685ab4e8f930627874ba4f4728e128"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Wed Sep 15 17:06:33 2010 -0400"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jaxboe@fusionio.com",
        "time": "Thu Sep 16 08:42:04 2010 +0200"
      },
      "message": "blk-cgroup: Prepare the base for supporting more than one IO control policies\n\no This patch prepares the base for introducing new IO control policies.\n  Currently all the code is written knowing there is only one policy\n  and that is proportional bandwidth. Creating infrastructure for newer\n  policies to come in.\n\no Also there were many functions which were generated using macro. It was\n  very confusing. Got rid of those.\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjaxboe@fusionio.com\u003e\n"
    },
    {
      "commit": "afc24d49c1e5dbeef745c1c1246f5ae6ebd97c71",
      "tree": "c936676ed21d032bf1d27f9ff1451f6242c8b3b6",
      "parents": [
        "e5ff082e8a68d9a6874990597497c7e6a96ad752"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Mon Apr 26 19:27:56 2010 +0200"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Mon Apr 26 19:27:56 2010 +0200"
      },
      "message": "blk-cgroup: config options re-arrangement\n\nThis patch fixes few usability and configurability issues.\n\no All the cgroup based controller options are configurable from\n  \"Genral Setup/Control Group Support/\" menu. blkio is the only exception.\n  Hence make this option visible in above menu and make it configurable from\n  there to bring it inline with rest of the cgroup based controllers.\n\no Get rid of CONFIG_DEBUG_CFQ_IOSCHED.\n\n  This option currently does two things.\n\n  - Enable printing of cgroup paths in blktrace\n  - Enables CONFIG_DEBUG_BLK_CGROUP, which in turn displays additional stat\n    files in cgroup.\n\n  If we are using group scheduling, blktrace data is of not really much use\n  if cgroup information is not present. To get this data, currently one has to\n  also enable CONFIG_DEBUG_CFQ_IOSCHED, which in turn brings the overhead of\n  all the additional debug stat files which is not desired.\n\n  Hence, this patch moves printing of cgroup paths under\n  CONFIG_CFQ_GROUP_IOSCHED.\n\n  This allows us to get rid of CONFIG_DEBUG_CFQ_IOSCHED completely. Now all\n  the debug stat files are controlled only by CONFIG_DEBUG_BLK_CGROUP which\n  can be enabled through config menu.\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nAcked-by: Divyesh Shah \u003cdpshah@google.com\u003e\nReviewed-by: Gui Jianfeng \u003cguijianfeng@cn.fujitsu.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "e5ff082e8a68d9a6874990597497c7e6a96ad752",
      "tree": "43c750821e89a50a01f4c7d73a68f779a57443fe",
      "parents": [
        "7f1dc8a2d2f45fc557b27fd56115338b1d34fc24"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Mon Apr 26 19:25:11 2010 +0200"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Mon Apr 26 19:25:11 2010 +0200"
      },
      "message": "blkio: Fix another BUG_ON() crash due to cfqq movement across groups\n\no Once in a while, I was hitting a BUG_ON() in blkio code. empty_time was\n  assuming that upon slice expiry, group can\u0027t be marked empty already (except\n  forced dispatch).\n\n  But this assumption is broken if cfqq can move (group_isolation\u003d0) across\n  groups after receiving a request.\n\n  I think most likely in this case we got a request in a cfqq and accounted\n  the rq in one group, later while adding the cfqq to tree, we moved the queue\n  to a different group which was already marked empty and after dispatch from\n  slice we found group already marked empty and raised alarm.\n\n  This patch does not error out if group is already marked empty. This can\n  introduce some empty_time stat error only in case of group_isolation\u003d0. This\n  is better than crashing. In case of group_isolation\u003d1 we should still get\n  same stats as before this patch.\n\n[  222.308546] ------------[ cut here ]------------\n[  222.309311] kernel BUG at block/blk-cgroup.c:236!\n[  222.309311] invalid opcode: 0000 [#1] SMP\n[  222.309311] last sysfs file: /sys/devices/virtual/block/dm-3/queue/scheduler\n[  222.309311] CPU 1\n[  222.309311] Modules linked in: dm_round_robin dm_multipath qla2xxx scsi_transport_fc dm_zero dm_mirror dm_region_hash dm_log dm_mod [last unloaded: scsi_wait_scan]\n[  222.309311]\n[  222.309311] Pid: 4780, comm: fio Not tainted 2.6.34-rc4-blkio-config #68 0A98h/HP xw8600 Workstation\n[  222.309311] RIP: 0010:[\u003cffffffff8121ad88\u003e]  [\u003cffffffff8121ad88\u003e] blkiocg_set_start_empty_time+0x50/0x83\n[  222.309311] RSP: 0018:ffff8800ba6e79f8  EFLAGS: 00010002\n[  222.309311] RAX: 0000000000000082 RBX: ffff8800a13b7990 RCX: ffff8800a13b7808\n[  222.309311] RDX: 0000000000002121 RSI: 0000000000000082 RDI: ffff8800a13b7a30\n[  222.309311] RBP: ffff8800ba6e7a18 R08: 0000000000000000 R09: 0000000000000001\n[  222.309311] R10: 000000000002f8c8 R11: ffff8800ba6e7ad8 R12: ffff8800a13b78ff\n[  222.309311] R13: ffff8800a13b7990 R14: 0000000000000001 R15: ffff8800a13b7808\n[  222.309311] FS:  00007f3beec476f0(0000) GS:ffff880001e40000(0000) knlGS:0000000000000000\n[  222.309311] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[  222.309311] CR2: 000000000040e7f0 CR3: 00000000a12d5000 CR4: 00000000000006e0\n[  222.309311] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n[  222.309311] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400\n[  222.309311] Process fio (pid: 4780, threadinfo ffff8800ba6e6000, task ffff8800b3d6bf00)\n[  222.309311] Stack:\n[  222.309311]  0000000000000001 ffff8800bab17a48 ffff8800bab17a48 ffff8800a13b7800\n[  222.309311] \u003c0\u003e ffff8800ba6e7a68 ffffffff8121da35 ffff880000000001 00ff8800ba5c5698\n[  222.309311] \u003c0\u003e ffff8800ba6e7a68 ffff8800a13b7800 0000000000000000 ffff8800bab17a48\n[  222.309311] Call Trace:\n[  222.309311]  [\u003cffffffff8121da35\u003e] __cfq_slice_expired+0x2af/0x3ec\n[  222.309311]  [\u003cffffffff8121fd7b\u003e] cfq_dispatch_requests+0x2c8/0x8e8\n[  222.309311]  [\u003cffffffff8120f1cd\u003e] ? spin_unlock_irqrestore+0xe/0x10\n[  222.309311]  [\u003cffffffff8120fb1a\u003e] ? blk_insert_cloned_request+0x70/0x7b\n[  222.309311]  [\u003cffffffff81210461\u003e] blk_peek_request+0x191/0x1a7\n[  222.309311]  [\u003cffffffffa0002799\u003e] dm_request_fn+0x38/0x14c [dm_mod]\n[  222.309311]  [\u003cffffffff810ae61f\u003e] ? sync_page_killable+0x0/0x35\n[  222.309311]  [\u003cffffffff81210fd4\u003e] __generic_unplug_device+0x32/0x37\n[  222.309311]  [\u003cffffffff81211274\u003e] generic_unplug_device+0x2e/0x3c\n[  222.309311]  [\u003cffffffffa00011a6\u003e] dm_unplug_all+0x42/0x5b [dm_mod]\n[  222.309311]  [\u003cffffffff8120ca37\u003e] blk_unplug+0x29/0x2d\n[  222.309311]  [\u003cffffffff8120ca4d\u003e] blk_backing_dev_unplug+0x12/0x14\n[  222.309311]  [\u003cffffffff81109a7a\u003e] block_sync_page+0x35/0x39\n[  222.309311]  [\u003cffffffff810ae616\u003e] sync_page+0x41/0x4a\n[  222.309311]  [\u003cffffffff810ae62d\u003e] sync_page_killable+0xe/0x35\n[  222.309311]  [\u003cffffffff8158aa59\u003e] __wait_on_bit_lock+0x46/0x8f\n[  222.309311]  [\u003cffffffff810ae4f5\u003e] __lock_page_killable+0x66/0x6d\n[  222.309311]  [\u003cffffffff81056f9c\u003e] ? wake_bit_function+0x0/0x33\n[  222.309311]  [\u003cffffffff810ae528\u003e] lock_page_killable+0x2c/0x2e\n[  222.309311]  [\u003cffffffff810afbc5\u003e] generic_file_aio_read+0x361/0x4f0\n[  222.309311]  [\u003cffffffff810ea044\u003e] do_sync_read+0xcb/0x108\n[  222.309311]  [\u003cffffffff811e42f7\u003e] ? security_file_permission+0x16/0x18\n[  222.309311]  [\u003cffffffff810ea6ab\u003e] vfs_read+0xab/0x108\n[  222.309311]  [\u003cffffffff810ea7c8\u003e] sys_read+0x4a/0x6e\n[  222.309311]  [\u003cffffffff81002b5b\u003e] system_call_fastpath+0x16/0x1b\n[  222.309311] Code: 58 01 00 00 00 48 89 c6 75 0a 48 83 bb 60 01 00 00 00 74 09 48 8d bb a0 00 00 00 eb 35 41 fe cc 74 0d f6 83 c0 01 00 00 04 74 04 \u003c0f\u003e 0b eb fe 48 89 75 e8 e8 be e0 de ff 66 83 8b c0 01 00 00 04\n[  222.309311] RIP  [\u003cffffffff8121ad88\u003e] blkiocg_set_start_empty_time+0x50/0x83\n[  222.309311]  RSP \u003cffff8800ba6e79f8\u003e\n[  222.309311] ---[ end trace 32b4f71dffc15712 ]---\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nAcked-by: Divyesh Shah \u003cdpshah@google.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "8d2a91f8960b230b8bbcc4d97ed2015f5271c87d",
      "tree": "54b742bd0ce37c1ec227178d23d7da347993a6b5",
      "parents": [
        "b6ac23af2c66e114d3a87ef28d56f1ceec283007"
      ],
      "author": {
        "name": "Divyesh Shah",
        "email": "dpshah@google.com",
        "time": "Fri Apr 16 08:10:51 2010 +0200"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Fri Apr 16 08:10:51 2010 +0200"
      },
      "message": "blkio: Initialize blkg-\u003estats_lock for the root cfqg too\n\nThis fixes the lockdep warning reported by Gui Jianfeng.\n\nSigned-off-by: Divyesh Shah \u003cdpshah@google.com\u003e\nReviewed-by: Gui Jianfeng \u003cguijianfeng@cn.fujitsu.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "a11cdaa7af56423a921a8bdad8f5a5f4ddca918a",
      "tree": "45309d760ab80347d4ad5a2cd249c988a507c636",
      "parents": [
        "da69da184c06f365b335a0e013dc6360a82abe85"
      ],
      "author": {
        "name": "Divyesh Shah",
        "email": "dpshah@google.com",
        "time": "Tue Apr 13 19:59:17 2010 +0200"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Tue Apr 13 19:59:17 2010 +0200"
      },
      "message": "block: Update to io-controller stats\n\nChangelog from v1:\no Call blkiocg_update_idle_time_stats() at cfq_rq_enqueued() instead of at\n  dispatch time.\n\nChangelog from original patchset: (in response to Vivek Goyal\u0027s comments)\no group blkiocg_update_blkio_group_dequeue_stats() with other DEBUG functions\no rename blkiocg_update_set_active_queue_stats() to\n  blkiocg_update_avg_queue_size_stats()\no s/request/io/ in blkiocg_update_request_add_stats() and\n  blkiocg_update_request_remove_stats()\no Call cfq_del_timer() at request dispatch() instead of\n  blkiocg_update_idle_time_stats()\n\nSigned-off-by: Divyesh Shah\u003cdpshah@google.com\u003e\nAcked-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "34d0f179d6dd711d3fc13c0820a456c59aae8048",
      "tree": "0e3d533e16cd7d99b0d28ec13353862f1da96dfd",
      "parents": [
        "812df48d127365ffd0869aa139738f572a86759c"
      ],
      "author": {
        "name": "Gui Jianfeng",
        "email": "guijianfeng@cn.fujitsu.com",
        "time": "Tue Apr 13 16:05:49 2010 +0800"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Tue Apr 13 10:14:20 2010 +0200"
      },
      "message": "io-controller: Add a new interface \"weight_device\" for IO-Controller\n\nCurrently, IO Controller makes use of blkio.weight to assign weight for\nall devices. Here a new user interface \"blkio.weight_device\" is introduced to\nassign different weights for different devices. blkio.weight becomes the\ndefault value for devices which are not configured by \"blkio.weight_device\"\n\nYou can use the following format to assigned specific weight for a given\ndevice:\n#echo \"major:minor weight\" \u003e blkio.weight_device\n\nmajor:minor represents device number.\n\nAnd you can remove weight for a given device as following:\n#echo \"major:minor 0\" \u003e blkio.weight_device\n\nV1-\u003eV2 changes:\n- use user interface \"weight_device\" instead of \"policy\" suggested by Vivek\n- rename some struct suggested by Vivek\n- rebase to 2.6-block \"for-linus\" branch\n- remove an useless list_empty check pointed out by Li Zefan\n- some trivial typo fix\n\nV2-\u003eV3 changes:\n- Move policy_*_node() functions up to get rid of forward declarations\n- rename related functions by adding prefix \"blkio_\"\n\nSigned-off-by: Gui Jianfeng \u003cguijianfeng@cn.fujitsu.com\u003e\nAcked-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "812df48d127365ffd0869aa139738f572a86759c",
      "tree": "772ef559057cd432ad874cd429287e7a912b1bb3",
      "parents": [
        "cdc1184cf4a7bd99f5473a91244197accc49146b"
      ],
      "author": {
        "name": "Divyesh Shah",
        "email": "dpshah@google.com",
        "time": "Thu Apr 08 21:15:35 2010 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Fri Apr 09 08:36:08 2010 +0200"
      },
      "message": "blkio: Add more debug-only per-cgroup stats\n\n1) group_wait_time - This is the amount of time the cgroup had to wait to get a\n  timeslice for one of its queues from when it became busy, i.e., went from 0\n  to 1 request queued. This is different from the io_wait_time which is the\n  cumulative total of the amount of time spent by each IO in that cgroup waiting\n  in the scheduler queue. This stat is a great way to find out any jobs in the\n  fleet that are being starved or waiting for longer than what is expected (due\n  to an IO controller bug or any other issue).\n2) empty_time - This is the amount of time a cgroup spends w/o any pending\n   requests. This stat is useful when a job does not seem to be able to use its\n   assigned disk share by helping check if that is happening due to an IO\n   controller bug or because the job is not submitting enough IOs.\n3) idle_time - This is the amount of time spent by the IO scheduler idling\n   for a given cgroup in anticipation of a better request than the exising ones\n   from other queues/cgroups.\n\nAll these stats are recorded using start and stop events. When reading these\nstats, we do not add the delta between the current time and the last start time\nif we\u0027re between the start and stop events. We avoid doing this to make sure\nthat these numbers are always monotonically increasing when read. Since we\u0027re\nusing sched_clock() which may use the tsc as its source, it may induce some\ninconsistency (due to tsc resync across cpus) if we included the current delta.\n\nSigned-off-by: Divyesh Shah\u003cdpshah@google.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "cdc1184cf4a7bd99f5473a91244197accc49146b",
      "tree": "ecd572867bfa5a82fa4ed16d7303448c7ea7d24c",
      "parents": [
        "812d402648f4fc1ab1091b2172a46fc1b367c724"
      ],
      "author": {
        "name": "Divyesh Shah",
        "email": "dpshah@google.com",
        "time": "Thu Apr 08 21:15:10 2010 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Fri Apr 09 08:36:08 2010 +0200"
      },
      "message": "blkio: Add io_queued and avg_queue_size stats\n\nThese stats are useful for getting a feel for the queue depth of the cgroup,\ni.e., how filled up its queues are at a given instant and over the existence of\nthe cgroup. This ability is useful when debugging problems in the wild as it\nhelps understand the application\u0027s IO pattern w/o having to read through the\nuserspace code (coz its tedious or just not available) or w/o the ability\nto run blktrace (since you may not have root access and/or not want to disturb\nperformance).\n\nSigned-off-by: Divyesh Shah\u003cdpshah@google.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "812d402648f4fc1ab1091b2172a46fc1b367c724",
      "tree": "9dc52d5bfdbc170559169a0157ed3295d551e9cf",
      "parents": [
        "84c124da9ff50bd71fab9c939ee5b7cd8bef2bd9"
      ],
      "author": {
        "name": "Divyesh Shah",
        "email": "dpshah@google.com",
        "time": "Thu Apr 08 21:14:23 2010 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Fri Apr 09 08:36:07 2010 +0200"
      },
      "message": "blkio: Add io_merged stat\n\nThis includes both the number of bios merged into requests belonging to this\ncgroup as well as the number of requests merged together.\nIn the past, we\u0027ve observed different merging behavior across upstream kernels,\nsome by design some actual bugs. This stat helps a lot in debugging such\nproblems when applications report decreased throughput with a new kernel\nversion.\n\nThis needed adding an extra elevator function to capture bios being merged as I\ndid not want to pollute elevator code with blkiocg knowledge and hence needed\nthe accounting invocation to come from CFQ.\n\nSigned-off-by: Divyesh Shah\u003cdpshah@google.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "84c124da9ff50bd71fab9c939ee5b7cd8bef2bd9",
      "tree": "f94ad03b56c71ebbe6b92265054c5e24af25b869",
      "parents": [
        "31373d09da5b7fe21fe6f781e92bd534a3495f00"
      ],
      "author": {
        "name": "Divyesh Shah",
        "email": "dpshah@google.com",
        "time": "Fri Apr 09 08:31:19 2010 +0200"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Fri Apr 09 08:31:19 2010 +0200"
      },
      "message": "blkio: Changes to IO controller additional stats patches\n\nthat include some minor fixes and addresses all comments.\n\nChangelog: (most based on Vivek Goyal\u0027s comments)\no renamed blkiocg_reset_write to blkiocg_reset_stats\no more clarification in the documentation on io_service_time and io_wait_time\no Initialize blkg-\u003estats_lock\no rename io_add_stat to blkio_add_stat and declare it static\no use bool for direction and sync\no derive direction and sync info from existing rq methods\no use 12 for major:minor string length\no define io_service_time better to cover the NCQ case\no add a separate reset_stats interface\no make the indexed stats a 2d array to simplify macro and function pointer code\no blkio.time now exports in jiffies as before\no Added stats description in patch description and\n  Documentation/cgroup/blkio-controller.txt\no Prefix all stats functions with blkio and make them static as applicable\no replace IO_TYPE_MAX with IO_TYPE_TOTAL\no Moved #define constant to top of blk-cgroup.c\no Pass dev_t around instead of char *\no Add note to documentation file about resetting stats\no use BLK_CGROUP_MODULE in addition to BLK_CGROUP config option in #ifdef\n  statements\no Avoid struct request specific knowledge in blk-cgroup. blk-cgroup.h now has\n  rq_direction() and rq_sync() functions which are used by CFQ and when using\n  io-controller at a higher level, bio_* functions can be added.\n\nSigned-off-by: Divyesh Shah\u003cdpshah@google.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "9195291e5f05e01d67f9a09c756b8aca8f009089",
      "tree": "e46a151fe39be2bc23d0683bedb2cbefe916fb5b",
      "parents": [
        "303a3acb2362f16c7e7f4c53b40c2f4b396dc8d5"
      ],
      "author": {
        "name": "Divyesh Shah",
        "email": "dpshah@google.com",
        "time": "Thu Apr 01 15:01:41 2010 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Fri Apr 02 08:44:37 2010 +0200"
      },
      "message": "blkio: Increment the blkio cgroup stats for real now\n\nWe also add start_time_ns and io_start_time_ns fields to struct request\nhere to record the time when a request is created and when it is\ndispatched to device. We use ns uints here as ms and jiffies are\nnot very useful for non-rotational media.\n\nSigned-off-by: Divyesh Shah\u003cdpshah@google.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "303a3acb2362f16c7e7f4c53b40c2f4b396dc8d5",
      "tree": "7996f28d5659fef44594f7049e30264b16baa62d",
      "parents": [
        "9a0785b0da561e1e9c6617df85e93ae107a42f18"
      ],
      "author": {
        "name": "Divyesh Shah",
        "email": "dpshah@google.com",
        "time": "Thu Apr 01 15:01:24 2010 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Fri Apr 02 08:44:36 2010 +0200"
      },
      "message": "blkio: Add io controller stats like\n\n- io_service_time\n- io_wait_time\n- io_serviced\n- io_service_bytes\n\nThese stats are accumulated per operation type helping us to distinguish between\nread and write, and sync and async IO. This patch does not increment any of\nthese stats.\n\nSigned-off-by: Divyesh Shah\u003cdpshah@google.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "9a0785b0da561e1e9c6617df85e93ae107a42f18",
      "tree": "56cb6b65f175a13c85976192216a6b8101b0d0f3",
      "parents": [
        "ed6b6dc7c142bfb5840d201a9b4a465c9e56ce33"
      ],
      "author": {
        "name": "Divyesh Shah",
        "email": "dpshah@google.com",
        "time": "Thu Apr 01 15:01:04 2010 -0700"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Fri Apr 02 08:44:36 2010 +0200"
      },
      "message": "blkio: Remove per-cfqq nr_sectors as we\u0027ll be passing\n\nthat info at request dispatch with other stats now. This patch removes the\nexisting support for accounting sectors for a blkio_group. This will be added\nback differently in the next two patches.\n\nSigned-off-by: Divyesh Shah\u003cdpshah@google.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "67523c48aa74d5637848edeccf285af1c60bf14a",
      "tree": "ebd14992e210c8dfb503ae5fdffc1f5392ad52df",
      "parents": [
        "8ca712ea84728531d36841ca8f98f9e8680bcf4e"
      ],
      "author": {
        "name": "Ben Blum",
        "email": "bblum@andrew.cmu.edu",
        "time": "Wed Mar 10 15:22:11 2010 -0800"
      },
      "committer": {
        "name": "Linus Torvalds",
        "email": "torvalds@linux-foundation.org",
        "time": "Fri Mar 12 15:52:36 2010 -0800"
      },
      "message": "cgroups: blkio subsystem as module\n\nModify the Block I/O cgroup subsystem to be able to be built as a module.\nAs the CFQ disk scheduler optionally depends on blk-cgroup, config options\nin block/Kconfig, block/Kconfig.iosched, and block/blk-cgroup.h are\nenhanced to support the new module dependency.\n\nSigned-off-by: Ben Blum \u003cbblum@andrew.cmu.edu\u003e\nCc: Li Zefan \u003clizf@cn.fujitsu.com\u003e\nCc: Paul Menage \u003cmenage@google.com\u003e\nCc: \"David S. Miller\" \u003cdavem@davemloft.net\u003e\nCc: KAMEZAWA Hiroyuki \u003ckamezawa.hiroyu@jp.fujitsu.com\u003e\nCc: Lai Jiangshan \u003claijs@cn.fujitsu.com\u003e\nCc: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nCc: Jens Axboe \u003cjens.axboe@oracle.com\u003e\nSigned-off-by: Andrew Morton \u003cakpm@linux-foundation.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@linux-foundation.org\u003e\n"
    },
    {
      "commit": "024f9066165ffe9c8284431c78adcbcddd309831",
      "tree": "11b64dd7861985aca57bd7624cd25c804afd4b1a",
      "parents": [
        "7f03292ee16e68be96aa88904afc6152f8d37736"
      ],
      "author": {
        "name": "Gui Jianfeng",
        "email": "guijianfeng@cn.fujitsu.com",
        "time": "Fri Feb 26 08:56:15 2010 +0100"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Fri Feb 26 08:56:15 2010 +0100"
      },
      "message": "cfq: Remove useless css reference get\n\nThere\u0027s no need to take css reference here, for the caller\nhas already called rcu_read_lock() to prevent cgroup from\nbeing removed.\n\nSigned-off-by: Gui Jianfeng \u003cguijianfeng@cn.fujitsu.com\u003e\nReviewed-by: Li Zefan \u003clizf@cn.fujitsu.com\u003e\nAcked-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "3e2520668970aab5a764044a298e987aafc1f63d",
      "tree": "088ebf7c4576d597774c8c332bab590dc3a472d6",
      "parents": [
        "9d6a986c0b276085f7944cd8ad65f4f82aff7536"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Fri Dec 04 10:36:42 2009 -0500"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Fri Dec 04 16:38:14 2009 +0100"
      },
      "message": "blkio: Implement dynamic io controlling policy registration\n\no One of the goals of block IO controller is that it should be able to\n  support mulitple io control policies, some of which be operational at\n  higher level in storage hierarchy.\n\no To begin with, we had one io controlling policy implemented by CFQ, and\n  I hard coded the CFQ functions called by blkio. This created issues when\n  CFQ is compiled as module.\n\no This patch implements a basic dynamic io controlling policy registration\n  functionality in blkio. This is similar to elevator functionality where\n  ioschedulers register the functions dynamically.\n\no Now in future, when more IO controlling policies are implemented, these\n  can dynakically register with block IO controller.\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "9d6a986c0b276085f7944cd8ad65f4f82aff7536",
      "tree": "1e72c813f4346ee329d5d427e214d183af78934f",
      "parents": [
        "b69f2292063d2caf37ca9aec7d63ded203701bf3"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Fri Dec 04 10:36:41 2009 -0500"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Fri Dec 04 16:38:14 2009 +0100"
      },
      "message": "blkio: Export some symbols from blkio as its user CFQ can be a module\n\no blkio controller is inside the kernel and cfq makes use of interfaces\n  exported by blkio. CFQ can be a module too, hence export symbols used\n  by CFQ.\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "2f5ea47712489a9d2d3cb832eb06062e4e64e0ec",
      "tree": "49c943cf46b83b4fc7da1a38d65cc7914e8ddbfb",
      "parents": [
        "72f924f62a6eb375c7c237ecc911f95be0531d1a"
      ],
      "author": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Thu Dec 03 21:06:43 2009 +0100"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Thu Dec 03 21:07:17 2009 +0100"
      },
      "message": "cfq-iosched: fix compile problem with !CONFIG_CGROUP\n\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "220841906fccafaf4094e87bdb6d252e20cf8c7c",
      "tree": "f25b1f057887cf2a05bb8309e0b757149e052797",
      "parents": [
        "2868ef7b39490e6b41c2c61cd9a5cd891e778b54"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Thu Dec 03 12:59:49 2009 -0500"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Thu Dec 03 19:28:52 2009 +0100"
      },
      "message": "blkio: Export disk time and sectors used by a group to user space\n\no Export disk time and sector used by a group to user space through cgroup\n  interface.\n\no Also export a \"dequeue\" interface to cgroup which keeps track of how many\n  a times a group was deleted from service tree. Helps in debugging.\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "2868ef7b39490e6b41c2c61cd9a5cd891e778b54",
      "tree": "e50e169e984d8bd201de2f73f98e31a65c028feb",
      "parents": [
        "b1c3576961847da26c91b1e97f226bb66be5fa3f"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Thu Dec 03 12:59:48 2009 -0500"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Thu Dec 03 19:28:52 2009 +0100"
      },
      "message": "blkio: Some debugging aids for CFQ\n\no Some debugging aids for CFQ.\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "b1c3576961847da26c91b1e97f226bb66be5fa3f",
      "tree": "e228525220031232463f9cbbe017bad67807e6d4",
      "parents": [
        "25fb5169d4c9d4255107abbb7c08ab712434efc8"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Thu Dec 03 12:59:47 2009 -0500"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Thu Dec 03 19:28:52 2009 +0100"
      },
      "message": "blkio: Take care of cgroup deletion and cfq group reference counting\n\no One can choose to change elevator or delete a cgroup. Implement group\n  reference counting so that both elevator exit and cgroup deletion can\n  take place gracefully.\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Nauman Rafique \u003cnauman@google.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    },
    {
      "commit": "31e4c28d95e64f2d5d3c497a3ecf37c62de635b4",
      "tree": "ffbb99b2565c4bdd4921fd7077164e7fc295b2bc",
      "parents": [
        "1fa8f6d68b5c8ca0a608fd8d296c5f07ac788cd6"
      ],
      "author": {
        "name": "Vivek Goyal",
        "email": "vgoyal@redhat.com",
        "time": "Thu Dec 03 12:59:42 2009 -0500"
      },
      "committer": {
        "name": "Jens Axboe",
        "email": "jens.axboe@oracle.com",
        "time": "Thu Dec 03 19:28:51 2009 +0100"
      },
      "message": "blkio: Introduce blkio controller cgroup interface\n\no This is basic implementation of blkio controller cgroup interface. This is\n  the common interface visible to user space and should be used by different\n  IO control policies as we implement those.\n\nSigned-off-by: Vivek Goyal \u003cvgoyal@redhat.com\u003e\nSigned-off-by: Jens Axboe \u003cjens.axboe@oracle.com\u003e\n"
    }
  ]
}