Omar Sandoval e94a7de2a3 sched/wait: Fix add_wait_queue() behavioral change ...

commit c6b9d9a330 upstream.

The following cleanup commit:

  50816c4899 ("sched/wait: Standardize internal naming of wait-queue entries")

... unintentionally changed the behavior of add_wait_queue() from
inserting the wait entry at the head of the wait queue to the tail
of the wait queue.

Beyond a negative performance impact this change in behavior
theoretically also breaks wait queues which mix exclusive and
non-exclusive waiters, as non-exclusive waiters will not be
woken up if they are queued behind enough exclusive waiters.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-team@fb.com
Fixes: ("sched/wait: Standardize internal naming of wait-queue entries")
Link: http://lkml.kernel.org/r/a16c8ccffd39bd08fdaa45a5192294c784b803a7.1512544324.git.osandov@fb.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2018-02-16 20:22:43 +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

…

completion.c

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02 11:10:55 +01:00

core.c

delayacct: Account blkio completion on the correct task

2018-01-23 19:58:13 +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

cpuacct.h

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

2018-01-02 20:31:05 +01:00

cpufreq.c

…

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

…

deadline.c

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02 11:10:55 +01:00

debug.c

sched/debug: Remove unused variable

2017-09-29 10:09:09 +02:00

fair.c

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02 11:10:55 +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

PM / s2idle: Rename ->enter_freeze to ->enter_s2idle

2017-08-11 01:29:56 +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

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02 11:10:55 +01:00

membarrier.c

membarrier: Disable preemption when calling smp_call_function_many()

2018-01-17 09:45:23 +01:00

rt.c

sched/rt: Do not pull from current CPU if only one CPU to pull

2017-12-20 10:10:21 +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

sched/rt: Simplify the IPI based RT balancing logic

2017-11-30 08:40:43 +00:00

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

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02 11:10:55 +01:00

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

sched/rt: Simplify the IPI based RT balancing logic

2017-11-30 08:40:43 +00:00

wait_bit.c

…

wait.c

sched/wait: Fix add_wait_queue() behavioral change

2018-02-16 20:22:43 +01:00