]> git.ipfire.org Git - thirdparty/linux.git/commit
sched/pelt: Use rq_clock_task() for hw_pressure
authorChen Yu <yu.c.chen@intel.com>
Tue, 27 Aug 2024 11:26:07 +0000 (19:26 +0800)
committerPeter Zijlstra <peterz@infradead.org>
Tue, 10 Sep 2024 07:51:14 +0000 (09:51 +0200)
commit84d265281d6cea65353fc24146280e0d86ac50cb
treef01baa56fc9337e491de8d7089645ef6368a87b1
parent5d871a63997fa8bcf80adb49ea1f2f7840dff932
sched/pelt: Use rq_clock_task() for hw_pressure

commit 97450eb90965 ("sched/pelt: Remove shift of thermal clock")
removed the decay_shift for hw_pressure. This commit uses the
sched_clock_task() in sched_tick() while it replaces the
sched_clock_task() with rq_clock_pelt() in __update_blocked_others().
This could bring inconsistence. One possible scenario I can think of
is in ___update_load_sum():

  u64 delta = now - sa->last_update_time

'now' could be calculated by rq_clock_pelt() from
__update_blocked_others(), and last_update_time was calculated by
rq_clock_task() previously from sched_tick(). Usually the former
chases after the latter, it cause a very large 'delta' and brings
unexpected behavior.

Fixes: 97450eb90965 ("sched/pelt: Remove shift of thermal clock")
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Hongyan Xia <hongyan.xia2@arm.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20240827112607.181206-1-yu.c.chen@intel.com
kernel/sched/fair.c