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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Kconfig | -rw-r--r-- | 12.4 KB |
Makefile | -rw-r--r-- | 2.4 KB |
altera_edac.c | -rw-r--r-- | 26.8 KB |
altera_edac.h | -rw-r--r-- | 6.0 KB |
amd64_edac.c | -rw-r--r-- | 77.7 KB |
amd64_edac.h | -rw-r--r-- | 13.0 KB |
amd64_edac_dbg.c | -rw-r--r-- | 1.5 KB |
amd64_edac_inj.c | -rw-r--r-- | 6.2 KB |
amd76x_edac.c | -rw-r--r-- | 9.4 KB |
amd8111_edac.c | -rw-r--r-- | 16.5 KB |
amd8111_edac.h | -rw-r--r-- | 4.1 KB |
amd8131_edac.c | -rw-r--r-- | 10.7 KB |
amd8131_edac.h | -rw-r--r-- | 3.7 KB |
cell_edac.c | -rw-r--r-- | 7.7 KB |
cpc925_edac.c | -rw-r--r-- | 31.7 KB |
debugfs.c | -rw-r--r-- | 4.0 KB |
e752x_edac.c | -rw-r--r-- | 40.8 KB |
e7xxx_edac.c | -rw-r--r-- | 16.2 KB |
edac_core.h | -rw-r--r-- | 14.3 KB |
edac_device.c | -rw-r--r-- | 19.4 KB |
edac_device_sysfs.c | -rw-r--r-- | 23.2 KB |
edac_mc.c | -rw-r--r-- | 32.8 KB |
edac_mc_sysfs.c | -rw-r--r-- | 26.2 KB |
edac_module.c | -rw-r--r-- | 3.3 KB |
edac_module.h | -rw-r--r-- | 4.5 KB |
edac_pci.c | -rw-r--r-- | 9.4 KB |
edac_pci_sysfs.c | -rw-r--r-- | 19.1 KB |
edac_stub.c | -rw-r--r-- | 1.6 KB |
ghes_edac.c | -rw-r--r-- | 13.6 KB |
highbank_l2_edac.c | -rw-r--r-- | 4.0 KB |
highbank_mc_edac.c | -rw-r--r-- | 7.5 KB |
i3000_edac.c | -rw-r--r-- | 13.8 KB |
i3200_edac.c | -rw-r--r-- | 12.8 KB |
i5000_edac.c | -rw-r--r-- | 42.3 KB |
i5100_edac.c | -rw-r--r-- | 30.3 KB |
i5400_edac.c | -rw-r--r-- | 40.0 KB |
i7300_edac.c | -rw-r--r-- | 35.3 KB |
i7core_edac.c | -rw-r--r-- | 63.1 KB |
i82443bxgx_edac.c | -rw-r--r-- | 13.6 KB |
i82860_edac.c | -rw-r--r-- | 9.2 KB |
i82875p_edac.c | -rw-r--r-- | 14.7 KB |
i82975x_edac.c | -rw-r--r-- | 18.3 KB |
ie31200_edac.c | -rw-r--r-- | 14.3 KB |
mce_amd.c | -rw-r--r-- | 25.8 KB |
mce_amd.h | -rw-r--r-- | 1.7 KB |
mpc85xx_edac.c | -rw-r--r-- | 34.9 KB |
mpc85xx_edac.h | -rw-r--r-- | 4.9 KB |
mv64x60_edac.c | -rw-r--r-- | 21.9 KB |
mv64x60_edac.h | -rw-r--r-- | 3.2 KB |
octeon_edac-l2c.c | -rw-r--r-- | 5.3 KB |
octeon_edac-lmc.c | -rw-r--r-- | 8.5 KB |
octeon_edac-pc.c | -rw-r--r-- | 3.5 KB |
octeon_edac-pci.c | -rw-r--r-- | 2.7 KB |
pasemi_edac.c | -rw-r--r-- | 8.6 KB |
ppc4xx_edac.c | -rw-r--r-- | 39.4 KB |
ppc4xx_edac.h | -rw-r--r-- | 7.2 KB |
r82600_edac.c | -rw-r--r-- | 11.8 KB |
sb_edac.c | -rw-r--r-- | 94.7 KB |
synopsys_edac.c | -rw-r--r-- | 13.4 KB |
tile_edac.c | -rw-r--r-- | 6.4 KB |
wq.c | -rw-r--r-- | 772 bytes |
x38_edac.c | -rw-r--r-- | 12.0 KB |
xgene_edac.c | -rw-r--r-- | 59.8 KB |
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