diff options
author | Matt Fleming <matt@codeblueprint.co.uk> | 2016-10-26 16:15:44 +0100 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2017-01-30 11:46:35 +0100 |
commit | 4d25b35ea3729affd37d69c78191ce6f92766e1a (patch) | |
tree | 013c49fa232779343680d3c8dd21871809dafd54 /kernel/sched | |
parent | 1b1d62254df0fe42a711eb71948f915918987790 (diff) | |
download | linux-4d25b35ea3729affd37d69c78191ce6f92766e1a.tar.bz2 |
sched/fair: Restore previous rq_flags when migrating tasks in hotplug
__migrate_task() can return with a different runqueue locked than the
one we passed as an argument. So that we can repin the lock in
migrate_tasks() (and keep the update_rq_clock() bit) we need to
restore the old rq_flags before repinning.
Note that it wouldn't be correct to change move_queued_task() to repin
because of the change of runqueue and the fact that having an
up-to-date clock on the initial rq doesn't mean the new rq has one
too.
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r-- | kernel/sched/core.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 7f983e83a353..3b248b03ad8f 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5608,7 +5608,7 @@ static void migrate_tasks(struct rq *dead_rq) { struct rq *rq = dead_rq; struct task_struct *next, *stop = rq->stop; - struct rq_flags rf; + struct rq_flags rf, old_rf; int dest_cpu; /* @@ -5669,6 +5669,13 @@ static void migrate_tasks(struct rq *dead_rq) continue; } + /* + * __migrate_task() may return with a different + * rq->lock held and a new cookie in 'rf', but we need + * to preserve rf::clock_update_flags for 'dead_rq'. + */ + old_rf = rf; + /* Find suitable destination for @next, with force if needed. */ dest_cpu = select_fallback_rq(dead_rq->cpu, next); @@ -5677,6 +5684,7 @@ static void migrate_tasks(struct rq *dead_rq) raw_spin_unlock(&rq->lock); rq = dead_rq; raw_spin_lock(&rq->lock); + rf = old_rf; } raw_spin_unlock(&next->pi_lock); } |