linux/kernel/sched
Josh Snyder c96f5471ce delayacct: Account blkio completion on the correct task
Before commit:

  e33a9bba85 ("sched/core: move IO scheduling accounting from io_schedule_timeout() into scheduler")

delayacct_blkio_end() was called after context-switching into the task which
completed I/O.

This resulted in double counting: the task would account a delay both waiting
for I/O and for time spent in the runqueue.

With e33a9bba85, delayacct_blkio_end() is called by try_to_wake_up().
In ttwu, we have not yet context-switched. This is more correct, in that
the delay accounting ends when the I/O is complete.

But delayacct_blkio_end() relies on 'get_current()', and we have not yet
context-switched into the task whose I/O completed. This results in the
wrong task having its delay accounting statistics updated.

Instead of doing that, pass the task_struct being woken to delayacct_blkio_end(),
so that it can update the statistics of the correct task.

Signed-off-by: Josh Snyder <joshs@netflix.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: <stable@vger.kernel.org>
Cc: Brendan Gregg <bgregg@netflix.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-block@vger.kernel.org
Fixes: e33a9bba85 ("sched/core: move IO scheduling accounting from io_schedule_timeout() into scheduler")
Link: http://lkml.kernel.org/r/1513613712-571-1-git-send-email-joshs@netflix.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-01-16 03:29:36 +01:00
..
autogroup.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
autogroup.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
clock.c sched/clock, sched/cputime: Use lockdep to assert IRQs are disabled/enabled 2017-11-08 11:13:53 +01:00
completion.c locking/lockdep: Remove cross-release leftovers 2018-01-08 17:30:45 +01:00
core.c delayacct: Account blkio completion on the correct task 2018-01-16 03:29:36 +01:00
cpuacct.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cpudeadline.c sched/deadline: Change return value of cpudl_find() 2017-08-10 12:18:17 +02:00
cpudeadline.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cpufreq_schedutil.c cpufreq: schedutil: Use idle_calls counter of the remote CPU 2017-12-28 12:26:54 +01:00
cpufreq.c cpufreq / sched: Pass flags to cpufreq_update_util() 2016-08-16 22:14:55 +02:00
cpupri.c sched/cpupri: Don't re-initialize 'struct cpupri' 2017-08-10 12:18:14 +02:00
cpupri.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cputime.c Merge branch 'for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2017-11-15 14:29:44 -08:00
deadline.c Merge branch 'for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2017-11-15 14:29:44 -08:00
debug.c sched/fair: Propagate an effective runnable_load_avg 2017-09-29 19:35:15 +02:00
fair.c sched/fair: Update and fix the runnable propagation rule 2017-12-06 19:30:50 +01:00
features.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
idle_task.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
idle.c sched/idle: Micro-optimize the idle loop 2017-10-26 08:31:29 +02:00
isolation.c sched/isolation: Add basic isolcpus flags 2017-10-27 09:55:31 +02:00
loadavg.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Makefile Merge branch 'linus' into sched/core, to pick up fixes 2017-11-08 10:17:15 +01:00
membarrier.c membarrier: Disable preemption when calling smp_call_function_many() 2018-01-10 08:50:31 +01:00
rt.c sched/rt: Do not pull from current CPU if only one CPU to pull 2017-12-15 16:28:02 +01:00
sched-pelt.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sched.h Merge branch 'for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2017-11-15 14:29:44 -08:00
stats.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
stats.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
stop_task.c Merge branch 'for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2017-11-15 14:29:44 -08:00
swait.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
topology.c Merge branch 'linus' into sched/core, to pick up fixes 2017-11-08 10:17:15 +01:00
wait_bit.c Pass mode to wait_on_atomic_t() action funcs and provide default actions 2017-11-13 15:38:16 +00:00
wait.c sched/wait: Fix add_wait_queue() behavioral change 2017-12-06 19:30:34 +01:00