)]}'
{
  "commit": "5160ee6fc891a9ca114be0e90fa6655647bb64b2",
  "tree": "35d3740a777935582af1b78238f20d2c2971ed55",
  "parents": [
    "21b6bf143d05d77c350d9c6764ae090a877b66ea"
  ],
  "author": {
    "name": "Eric Dumazet",
    "email": "dada1@cosmosbay.com",
    "time": "Sun Jan 08 01:03:32 2006 -0800"
  },
  "committer": {
    "name": "Linus Torvalds",
    "email": "torvalds@g5.osdl.org",
    "time": "Sun Jan 08 20:13:58 2006 -0800"
  },
  "message": "[PATCH] shrink dentry struct\n\nSome long time ago, dentry struct was carefully tuned so that on 32 bits\nUP, sizeof(struct dentry) was exactly 128, ie a power of 2, and a multiple\nof memory cache lines.\n\nThen RCU was added and dentry struct enlarged by two pointers, with nice\nresults for SMP, but not so good on UP, because breaking the above tuning\n(128 + 8 \u003d 136 bytes)\n\nThis patch reverts this unwanted side effect, by using an union (d_u),\nwhere d_rcu and d_child are placed so that these two fields can share their\nmemory needs.\n\nAt the time d_free() is called (and d_rcu is really used), d_child is known\nto be empty and not touched by the dentry freeing.\n\nLockless lookups only access d_name, d_parent, d_lock, d_op, d_flags (so\nthe previous content of d_child is not needed if said dentry was unhashed\nbut still accessed by a CPU because of RCU constraints)\n\nAs dentry cache easily contains millions of entries, a size reduction is\nworth the extra complexity of the ugly C union.\n\nSigned-off-by: Eric Dumazet \u003cdada1@cosmosbay.com\u003e\nCc: Dipankar Sarma \u003cdipankar@in.ibm.com\u003e\nCc: Maneesh Soni \u003cmaneesh@in.ibm.com\u003e\nCc: Miklos Szeredi \u003cmiklos@szeredi.hu\u003e\nCc: \"Paul E. McKenney\" \u003cpaulmck@us.ibm.com\u003e\nCc: Ian Kent \u003craven@themaw.net\u003e\nCc: Paul Jackson \u003cpj@sgi.com\u003e\nCc: Al Viro \u003cviro@ftp.linux.org.uk\u003e\nCc: Christoph Hellwig \u003chch@lst.de\u003e\nCc: Trond Myklebust \u003ctrond.myklebust@fys.uio.no\u003e\nCc: Neil Brown \u003cneilb@cse.unsw.edu.au\u003e\nCc: James Morris \u003cjmorris@namei.org\u003e\nCc: Stephen Smalley \u003csds@epoch.ncsc.mil\u003e\nSigned-off-by: Andrew Morton \u003cakpm@osdl.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@osdl.org\u003e\n",
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