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author | Brian Silverman <brian@peloton-tech.com> | 2015-02-19 03:23:56 +0300 |
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committer | Jiri Slaby <jslaby@suse.cz> | 2015-04-22 09:58:34 +0300 |
commit | f9212814b6925eaba8f089bcc110ba5aec1ef13d (patch) | |
tree | 2a6aa8226fe0abd7cc09118145b0f4f055b23e7c /mm/page-writeback.c | |
parent | f875b0d329823b41e4b0c47176bc25ab24d9bbc8 (diff) | |
download | linux-f9212814b6925eaba8f089bcc110ba5aec1ef13d.tar.xz |
sched: Fix RLIMIT_RTTIME when PI-boosting to RT
commit 746db9443ea57fd9c059f62c4bfbf41cf224fe13 upstream.
When non-realtime tasks get priority-inheritance boosted to a realtime
scheduling class, RLIMIT_RTTIME starts to apply to them. However, the
counter used for checking this (the same one used for SCHED_RR
timeslices) was not getting reset. This meant that tasks running with a
non-realtime scheduling class which are repeatedly boosted to a realtime
one, but never block while they are running realtime, eventually hit the
timeout without ever running for a time over the limit. This patch
resets the realtime timeslice counter when un-PI-boosting from an RT to
a non-RT scheduling class.
I have some test code with two threads and a shared PTHREAD_PRIO_INHERIT
mutex which induces priority boosting and spins while boosted that gets
killed by a SIGXCPU on non-fixed kernels but doesn't with this patch
applied. It happens much faster with a CONFIG_PREEMPT_RT kernel, and
does happen eventually with PREEMPT_VOLUNTARY kernels.
Signed-off-by: Brian Silverman <brian@peloton-tech.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: austin@peloton-tech.com
Link: http://lkml.kernel.org/r/1424305436-6716-1-git-send-email-brian@peloton-tech.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'mm/page-writeback.c')
0 files changed, 0 insertions, 0 deletions