Revision 2548d546d40c0014efdde88a53bf7896e917dcce authored by Peter Zijlstra on 21 April 2016, 16:03:15 UTC, committed by Ingo Molnar on 28 April 2016, 08:28:55 UTC
Chris Metcalf reported a that sched_can_stop_tick() sometimes fails to re-enable the tick. His observed problem is that rq->cfs.nr_running can be 1 even though there are multiple runnable CFS tasks. This happens in the cgroup case, in which case cfs.nr_running is the number of runnable entities for that level. If there is a single runnable cgroup (which can have an arbitrary number of runnable child entries itself) rq->cfs.nr_running will be 1. However, looking at that function I think there's more problems with it. It seems to assume that if there's FIFO tasks, those will run. This is incorrect. The FIFO task can have a lower prio than an RR task, in which case the RR task will run. So the whole fifo_nr_running test seems misplaced, it should go after the rr_nr_running tests. That is, only if !rr_nr_running, can we use fifo_nr_running like this. Reported-by: Chris Metcalf <cmetcalf@mellanox.com> Tested-by: Chris Metcalf <cmetcalf@mellanox.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Wanpeng Li <kernellwp@gmail.com> Fixes: 76d92ac305f2 ("sched: Migrate sched to use new tick dependency mask model") Link: http://lkml.kernel.org/r/20160421160315.GK24771@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
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bcache | ||
persistent-data | ||
Kconfig | -rw-r--r-- | 16.3 KB |
Makefile | -rw-r--r-- | 2.5 KB |
bitmap.c | -rw-r--r-- | 64.3 KB |
bitmap.h | -rw-r--r-- | 9.6 KB |
dm-bio-prison.c | -rw-r--r-- | 9.7 KB |
dm-bio-prison.h | -rw-r--r-- | 4.4 KB |
dm-bio-record.h | -rw-r--r-- | 936 bytes |
dm-bufio.c | -rw-r--r-- | 47.1 KB |
dm-bufio.h | -rw-r--r-- | 3.9 KB |
dm-builtin.c | -rw-r--r-- | 2.0 KB |
dm-cache-block-types.h | -rw-r--r-- | 1.1 KB |
dm-cache-metadata.c | -rw-r--r-- | 34.9 KB |
dm-cache-metadata.h | -rw-r--r-- | 5.1 KB |
dm-cache-policy-cleaner.c | -rw-r--r-- | 10.1 KB |
dm-cache-policy-internal.h | -rw-r--r-- | 4.4 KB |
dm-cache-policy-smq.c | -rw-r--r-- | 41.6 KB |
dm-cache-policy.c | -rw-r--r-- | 3.6 KB |
dm-cache-policy.h | -rw-r--r-- | 8.2 KB |
dm-cache-target.c | -rw-r--r-- | 94.1 KB |
dm-crypt.c | -rw-r--r-- | 50.5 KB |
dm-delay.c | -rw-r--r-- | 8.1 KB |
dm-era-target.c | -rw-r--r-- | 38.1 KB |
dm-exception-store.c | -rw-r--r-- | 6.4 KB |
dm-exception-store.h | -rw-r--r-- | 5.7 KB |
dm-flakey.c | -rw-r--r-- | 9.5 KB |
dm-io.c | -rw-r--r-- | 13.1 KB |
dm-ioctl.c | -rw-r--r-- | 42.4 KB |
dm-kcopyd.c | -rw-r--r-- | 18.8 KB |
dm-linear.c | -rw-r--r-- | 3.4 KB |
dm-log-userspace-base.c | -rw-r--r-- | 22.0 KB |
dm-log-userspace-transfer.c | -rw-r--r-- | 7.1 KB |
dm-log-userspace-transfer.h | -rw-r--r-- | 467 bytes |
dm-log-writes.c | -rw-r--r-- | 19.9 KB |
dm-log.c | -rw-r--r-- | 20.0 KB |
dm-mpath.c | -rw-r--r-- | 41.0 KB |
dm-mpath.h | -rw-r--r-- | 415 bytes |
dm-path-selector.c | -rw-r--r-- | 2.4 KB |
dm-path-selector.h | -rw-r--r-- | 2.3 KB |
dm-queue-length.c | -rw-r--r-- | 5.9 KB |
dm-raid.c | -rw-r--r-- | 47.3 KB |
dm-raid1.c | -rw-r--r-- | 34.9 KB |
dm-region-hash.c | -rw-r--r-- | 18.0 KB |
dm-round-robin.c | -rw-r--r-- | 6.0 KB |
dm-service-time.c | -rw-r--r-- | 8.8 KB |
dm-snap-persistent.c | -rw-r--r-- | 22.4 KB |
dm-snap-transient.c | -rw-r--r-- | 3.7 KB |
dm-snap.c | -rw-r--r-- | 57.1 KB |
dm-stats.c | -rw-r--r-- | 29.3 KB |
dm-stats.h | -rw-r--r-- | 949 bytes |
dm-stripe.c | -rw-r--r-- | 9.8 KB |
dm-switch.c | -rw-r--r-- | 15.3 KB |
dm-sysfs.c | -rw-r--r-- | 3.1 KB |
dm-table.c | -rw-r--r-- | 39.6 KB |
dm-target.c | -rw-r--r-- | 3.1 KB |
dm-thin-metadata.c | -rw-r--r-- | 44.3 KB |
dm-thin-metadata.h | -rw-r--r-- | 6.7 KB |
dm-thin.c | -rw-r--r-- | 107.7 KB |
dm-uevent.c | -rw-r--r-- | 5.3 KB |
dm-uevent.h | -rw-r--r-- | 1.6 KB |
dm-verity-fec.c | -rw-r--r-- | 20.5 KB |
dm-verity-fec.h | -rw-r--r-- | 4.3 KB |
dm-verity-target.c | -rw-r--r-- | 25.3 KB |
dm-verity.h | -rw-r--r-- | 3.5 KB |
dm-zero.c | -rw-r--r-- | 1.5 KB |
dm.c | -rw-r--r-- | 86.4 KB |
dm.h | -rw-r--r-- | 7.4 KB |
faulty.c | -rw-r--r-- | 9.0 KB |
linear.c | -rw-r--r-- | 7.5 KB |
linear.h | -rw-r--r-- | 212 bytes |
md-cluster.c | -rw-r--r-- | 32.3 KB |
md-cluster.h | -rw-r--r-- | 1.0 KB |
md.c | -rw-r--r-- | 229.6 KB |
md.h | -rw-r--r-- | 22.6 KB |
multipath.c | -rw-r--r-- | 13.2 KB |
multipath.h | -rw-r--r-- | 611 bytes |
raid0.c | -rw-r--r-- | 18.2 KB |
raid0.h | -rw-r--r-- | 412 bytes |
raid1.c | -rw-r--r-- | 86.9 KB |
raid1.h | -rw-r--r-- | 5.3 KB |
raid10.c | -rw-r--r-- | 127.8 KB |
raid10.h | -rw-r--r-- | 4.1 KB |
raid5-cache.c | -rw-r--r-- | 33.5 KB |
raid5.c | -rw-r--r-- | 223.5 KB |
raid5.h | -rw-r--r-- | 23.8 KB |
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