cfq: don't use icq_get_changed()
cfq caches the associated cfqq's for a given cic. The cache needs to
be flushed if the cic's ioprio or blkcg has changed. It is currently
done by requiring the changing action to set the respective
ICQ_*_CHANGED bit in the icq and testing it from cfq_set_request(),
which involves iterating through all the affected icqs.
All cfq wants to know is whether ioprio and/or blkcg have changed
since the last flush and can be easily achieved by just remembering
the current ioprio and blkcg ID in cic.
This patch adds cic->{ioprio|blkcg_id}, updates all ioprio users to
use the remembered value instead, and updates cfq_set_request() path
such that, instead of using icq_get_changed(), the current values are
compared against the remembered ones and trigger appropriate flush
action if not. Condition tests are moved inside both _changed
functions which are now named check_ioprio_changed() and
check_blkcg_changed().
ioprio.h::task_ioprio*() can't be used anymore and replaced with
open-coded IOPRIO_CLASS_NONE case in cfq_async_queue_prio().
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/include/linux/ioprio.h b/include/linux/ioprio.h
index 76dad48..beb9ce1 100644
--- a/include/linux/ioprio.h
+++ b/include/linux/ioprio.h
@@ -42,26 +42,14 @@
};
/*
+ * Fallback BE priority
+ */
+#define IOPRIO_NORM (4)
+
+/*
* if process has set io priority explicitly, use that. if not, convert
* the cpu scheduler nice value to an io priority
*/
-#define IOPRIO_NORM (4)
-static inline int task_ioprio(struct io_context *ioc)
-{
- if (ioprio_valid(ioc->ioprio))
- return IOPRIO_PRIO_DATA(ioc->ioprio);
-
- return IOPRIO_NORM;
-}
-
-static inline int task_ioprio_class(struct io_context *ioc)
-{
- if (ioprio_valid(ioc->ioprio))
- return IOPRIO_PRIO_CLASS(ioc->ioprio);
-
- return IOPRIO_CLASS_BE;
-}
-
static inline int task_nice_ioprio(struct task_struct *task)
{
return (task_nice(task) + 20) / 5;