diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2017-09-07 11:13:38 +0200 |
|---|---|---|
| committer | Moyster <oysterized@gmail.com> | 2019-05-02 16:49:51 +0200 |
| commit | e135d6e85c3d71d27f0e583138767dc82836a8a5 (patch) | |
| tree | 45e5a040abc16f2b82ce765b300a332b248a245b /kernel/sched | |
| parent | 4e97a07b7232fe63b57c98dd83343282bcb72638 (diff) | |
sched/cpuset/pm: Fix cpuset vs. suspend-resume bugs
commit 50e76632339d4655859523a39249dd95ee5e93e7 upstream.
Cpusets vs. suspend-resume is _completely_ broken. And it got noticed
because it now resulted in non-cpuset usage breaking too.
On suspend cpuset_cpu_inactive() doesn't call into
cpuset_update_active_cpus() because it doesn't want to move tasks about,
there is no need, all tasks are frozen and won't run again until after
we've resumed everything.
But this means that when we finally do call into
cpuset_update_active_cpus() after resuming the last frozen cpu in
cpuset_cpu_active(), the top_cpuset will not have any difference with
the cpu_active_mask and this it will not in fact do _anything_.
So the cpuset configuration will not be restored. This was largely
hidden because we would unconditionally create identity domains and
mobile users would not in fact use cpusets much. And servers what do use
cpusets tend to not suspend-resume much.
An addition problem is that we'd not in fact wait for the cpuset work to
finish before resuming the tasks, allowing spurious migrations outside
of the specified domains.
Fix the rebuild by introducing cpuset_force_rebuild() and fix the
ordering with cpuset_wait_for_hotplug().
Reported-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: deb7aa308ea2 ("cpuset: reorganize CPU / memory hotplug handling")
Link: http://lkml.kernel.org/r/20170907091338.orwxrqkbfkki3c24@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Change-Id: Ia40ffcf49507af1d5493d7e534e9433ca346db02
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/core.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 265f8359e..827544592 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7443,17 +7443,16 @@ static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, * operation in the resume sequence, just build a single sched * domain, ignoring cpusets. */ - num_cpus_frozen--; - if (likely(num_cpus_frozen)) { - partition_sched_domains(1, NULL, NULL); + partition_sched_domains(1, NULL, NULL); + if (--num_cpus_frozen) break; - } /* * This is the last CPU online operation. So fall through and * restore the original sched domains by considering the * cpuset configurations. */ + cpuset_force_rebuild(); case CPU_ONLINE: case CPU_DOWN_FAILED: |