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7f51412a41
Exclusive cpusets are the only way users can restrict SCHED_DEADLINE tasks affinity (performing what is commonly called clustered scheduling). Unfortunately, such thing is currently broken for two reasons: - No check is performed when the user tries to attach a task to an exlusive cpuset (recall that exclusive cpusets have an associated maximum allowed bandwidth). - Bandwidths of source and destination cpusets are not correctly updated after a task is migrated between them. This patch fixes both things at once, as they are opposite faces of the same coin. The check is performed in cpuset_can_attach(), as there aren't any points of failure after that function. The updated is split in two halves. We first reserve bandwidth in the destination cpuset, after we pass the check in cpuset_can_attach(). And we then release bandwidth from the source cpuset when the task's affinity is actually changed. Even if there can be time windows when sched_setattr() may erroneously fail in the source cpuset, we are fine with it, as we can't perfom an atomic update of both cpusets at once. Reported-by: Daniel Wagner <daniel.wagner@bmw-carit.de> Reported-by: Vincent Legout <vincent@legout.info> Signed-off-by: Juri Lelli <juri.lelli@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Dario Faggioli <raistlin@linux.it> Cc: Michael Trimarchi <michael@amarulasolutions.com> Cc: Fabio Checconi <fchecconi@gmail.com> Cc: michael@amarulasolutions.com Cc: luca.abeni@unitn.it Cc: Li Zefan <lizefan@huawei.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: cgroups@vger.kernel.org Link: http://lkml.kernel.org/r/1411118561-26323-3-git-send-email-juri.lelli@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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| .. | ||
| auto_group.c | ||
| auto_group.h | ||
| clock.c | ||
| completion.c | ||
| core.c | ||
| cpuacct.c | ||
| cpuacct.h | ||
| cpudeadline.c | ||
| cpudeadline.h | ||
| cpupri.c | ||
| cpupri.h | ||
| cputime.c | ||
| deadline.c | ||
| debug.c | ||
| fair.c | ||
| features.h | ||
| idle_task.c | ||
| idle.c | ||
| Makefile | ||
| proc.c | ||
| rt.c | ||
| sched.h | ||
| stats.c | ||
| stats.h | ||
| stop_task.c | ||
| wait.c | ||