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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altera-stapl | ||
c2port | ||
cb710 | ||
cxl | ||
echo | ||
eeprom | ||
genwqe | ||
ibmasm | ||
lis3lv02d | ||
mei | ||
mic | ||
sgi-gru | ||
sgi-xp | ||
ti-st | ||
vmw_vmci | ||
Kconfig | -rw-r--r-- | 29.0 KB |
Makefile | -rw-r--r-- | 2.2 KB |
ad525x_dpot-i2c.c | -rw-r--r-- | 2.6 KB |
ad525x_dpot-spi.c | -rw-r--r-- | 2.8 KB |
ad525x_dpot.c | -rw-r--r-- | 20.1 KB |
ad525x_dpot.h | -rw-r--r-- | 7.9 KB |
apds9802als.c | -rw-r--r-- | 7.6 KB |
apds990x.c | -rw-r--r-- | 33.9 KB |
arm-charlcd.c | -rw-r--r-- | 8.8 KB |
atmel-ssc.c | -rw-r--r-- | 5.1 KB |
atmel_tclib.c | -rw-r--r-- | 4.5 KB |
bh1770glc.c | -rw-r--r-- | 37.5 KB |
bh1780gli.c | -rw-r--r-- | 6.1 KB |
bmp085-i2c.c | -rw-r--r-- | 2.2 KB |
bmp085-spi.c | -rw-r--r-- | 2.1 KB |
bmp085.c | -rw-r--r-- | 13.3 KB |
bmp085.h | -rw-r--r-- | 1.1 KB |
cs5535-mfgpt.c | -rw-r--r-- | 10.2 KB |
ds1682.c | -rw-r--r-- | 6.6 KB |
dummy-irq.c | -rw-r--r-- | 1.5 KB |
enclosure.c | -rw-r--r-- | 18.7 KB |
fsa9480.c | -rw-r--r-- | 12.8 KB |
hmc6352.c | -rw-r--r-- | 4.0 KB |
hpilo.c | -rw-r--r-- | 21.6 KB |
hpilo.h | -rw-r--r-- | 5.7 KB |
ics932s401.c | -rw-r--r-- | 13.2 KB |
ioc4.c | -rw-r--r-- | 14.3 KB |
isl29003.c | -rw-r--r-- | 11.6 KB |
isl29020.c | -rw-r--r-- | 5.5 KB |
kgdbts.c | -rw-r--r-- | 30.6 KB |
lattice-ecp3-config.c | -rw-r--r-- | 5.9 KB |
lkdtm.c | -rw-r--r-- | 23.2 KB |
panel.c | -rw-r--r-- | 61.4 KB |
pch_phub.c | -rw-r--r-- | 27.5 KB |
phantom.c | -rw-r--r-- | 13.2 KB |
pti.c | -rw-r--r-- | 26.4 KB |
qcom-coincell.c | -rw-r--r-- | 4.0 KB |
spear13xx_pcie_gadget.c | -rw-r--r-- | 19.9 KB |
sram.c | -rw-r--r-- | 10.2 KB |
ti_dac7512.c | -rw-r--r-- | 2.5 KB |
tifm_7xx1.c | -rw-r--r-- | 11.0 KB |
tifm_core.c | -rw-r--r-- | 8.3 KB |
tsl2550.c | -rw-r--r-- | 10.5 KB |
vexpress-syscfg.c | -rw-r--r-- | 7.1 KB |
vmw_balloon.c | -rw-r--r-- | 33.8 KB |
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