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a148866489
linux/kernel/sched
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Peter Zijlstra a148866489 sched: Replace rq::wake_list 
The recent commit: 90b5363acd ("sched: Clean up scheduler_ipi()")
got smp_call_function_single_async() subtly wrong. Even though it will
return -EBUSY when trying to re-use a csd, that condition is not
atomic and still requires external serialization.

The change in ttwu_queue_remote() got this wrong.

While on first reading ttwu_queue_remote() has an atomic test-and-set
that appears to serialize the use, the matching 'release' is not in
the right place to actually guarantee this serialization.

The actual race is vs the sched_ttwu_pending() call in the idle loop;
that can run the wakeup-list without consuming the CSD.

Instead of trying to chain the lists, merge them.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200526161908.129371594@infradead.org
2020-05-28 10:54:16 +02:00
..
autogroup.c sched/autogroup: Make autogroup_path() always available 2019-06-24 19:23:40 +02:00
autogroup.h
clock.c sched/clock: Use static_branch_likely() with sched_clock_running 2019-11-29 08:10:54 +01:00
completion.c completion: Use lockdep_assert_RT_in_threaded_ctx() in complete_all() 2020-03-23 18:40:25 +01:00
core.c sched: Replace rq::wake_list 2020-05-28 10:54:16 +02:00
cpuacct.c sched/cpuacct: Fix charge cpuacct.usage_sys 2020-05-19 20:34:14 +02:00
cpudeadline.c
cpudeadline.h
cpufreq_schedutil.c sched/uclamp: Rename uclamp_util_with() into uclamp_rq_util_with() 2019-12-25 10:42:08 +01:00
cpufreq.c cpufreq: Avoid leaving stale IRQ work items during CPU offline 2019-12-12 17:59:43 +01:00
cpupri.c sched/rt: cpupri_find: Trigger a full search as fallback 2020-03-20 13:06:20 +01:00
cpupri.h sched/rt: Optimize cpupri_find() on non-heterogenous systems 2020-03-06 12:57:27 +01:00
cputime.c sched/vtime: Work around an unitialized variable warning 2020-04-15 11:06:50 +02:00
deadline.c sched/deadline: Make two functions static 2020-03-06 12:57:24 +01:00
debug.c sched: Add rq::ttwu_pending 2020-05-28 10:54:16 +02:00
fair.c sched: Add rq::ttwu_pending 2020-05-28 10:54:16 +02:00
features.h sched/fair/util_est: Implement faster ramp-up EWMA on utilization increases 2019-10-29 10:01:07 +01:00
idle.c sched: Replace rq::wake_list 2020-05-28 10:54:16 +02:00
isolation.c sched/isolation: Allow "isolcpus=" to skip unknown sub-parameters 2020-04-15 10:38:26 +02:00
loadavg.c timers/nohz: Update NOHZ load in remote tick 2020-01-28 21:36:44 +01:00
Makefile
membarrier.c membarrier: Fix RCU locking bug caused by faulty merge 2019-10-01 21:27:50 +02:00
pelt.c sched/pelt: Sync util/runnable_sum with PELT window when propagating 2020-05-19 20:34:14 +02:00
pelt.h sched/pelt: Add support to track thermal pressure 2020-03-06 12:57:17 +01:00
psi.c psi: Move PF_MEMSTALL out of task->flags 2020-03-20 13:06:19 +01:00
rt.c sched: Defend cfs and rt bandwidth quota against overflow 2020-05-19 20:34:14 +02:00
sched-pelt.h sched/fair: Fix "runnable_avg_yN_inv" not used warnings 2019-06-17 12:15:58 +02:00
sched.h sched: Replace rq::wake_list 2020-05-28 10:54:16 +02:00
stats.c
stats.h psi: Move PF_MEMSTALL out of task->flags 2020-03-20 13:06:19 +01:00
stop_task.c sched/core: Further clarify sched_class::set_next_task() 2019-11-11 08:35:21 +01:00
swait.c sched/swait: Prepare usage in completions 2020-03-21 16:00:23 +01:00
topology.c sched/topology: Kill SD_LOAD_BALANCE 2020-04-30 20:14:39 +02:00
wait_bit.c sched/wait: fix ___wait_var_event(exclusive) 2019-12-17 13:32:50 +01:00
wait.c Add wake_up_interruptible_sync_poll_locked() 2019-10-31 15:12:23 +00:00