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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File | Mode | Size |
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Kconfig | -rw-r--r-- | 11.9 KB |
Makefile | -rw-r--r-- | 2.7 KB |
phy-armada375-usb2.c | -rw-r--r-- | 4.3 KB |
phy-bcm-cygnus-pcie.c | -rw-r--r-- | 5.1 KB |
phy-bcm-kona-usb2.c | -rw-r--r-- | 3.8 KB |
phy-berlin-sata.c | -rw-r--r-- | 7.2 KB |
phy-berlin-usb.c | -rw-r--r-- | 6.1 KB |
phy-brcmstb-sata.c | -rw-r--r-- | 6.4 KB |
phy-core.c | -rw-r--r-- | 22.6 KB |
phy-dm816x-usb.c | -rw-r--r-- | 7.5 KB |
phy-exynos-dp-video.c | -rw-r--r-- | 3.4 KB |
phy-exynos-mipi-video.c | -rw-r--r-- | 5.2 KB |
phy-exynos4210-usb2.c | -rw-r--r-- | 7.0 KB |
phy-exynos4x12-usb2.c | -rw-r--r-- | 10.5 KB |
phy-exynos5-usbdrd.c | -rw-r--r-- | 20.8 KB |
phy-exynos5250-sata.c | -rw-r--r-- | 6.9 KB |
phy-exynos5250-usb2.c | -rw-r--r-- | 12.8 KB |
phy-hi6220-usb.c | -rw-r--r-- | 4.1 KB |
phy-hix5hd2-sata.c | -rw-r--r-- | 5.3 KB |
phy-lpc18xx-usb-otg.c | -rw-r--r-- | 3.4 KB |
phy-miphy28lp.c | -rw-r--r-- | 33.4 KB |
phy-miphy365x.c | -rw-r--r-- | 15.9 KB |
phy-mt65xx-usb3.c | -rw-r--r-- | 17.4 KB |
phy-mvebu-sata.c | -rw-r--r-- | 3.4 KB |
phy-omap-control.c | -rw-r--r-- | 9.5 KB |
phy-omap-usb2.c | -rw-r--r-- | 10.8 KB |
phy-pistachio-usb.c | -rw-r--r-- | 5.2 KB |
phy-pxa-28nm-hsic.c | -rw-r--r-- | 5.8 KB |
phy-pxa-28nm-usb2.c | -rw-r--r-- | 9.7 KB |
phy-qcom-apq8064-sata.c | -rw-r--r-- | 8.5 KB |
phy-qcom-ipq806x-sata.c | -rw-r--r-- | 6.5 KB |
phy-qcom-ufs-i.h | -rw-r--r-- | 4.8 KB |
phy-qcom-ufs-qmp-14nm.c | -rw-r--r-- | 5.3 KB |
phy-qcom-ufs-qmp-14nm.h | -rw-r--r-- | 8.2 KB |
phy-qcom-ufs-qmp-20nm.c | -rw-r--r-- | 6.8 KB |
phy-qcom-ufs-qmp-20nm.h | -rw-r--r-- | 11.2 KB |
phy-qcom-ufs.c | -rw-r--r-- | 18.8 KB |
phy-rcar-gen2.c | -rw-r--r-- | 8.2 KB |
phy-rcar-gen3-usb2.c | -rw-r--r-- | 8.4 KB |
phy-rockchip-dp.c | -rw-r--r-- | 3.7 KB |
phy-rockchip-emmc.c | -rw-r--r-- | 6.1 KB |
phy-rockchip-usb.c | -rw-r--r-- | 12.5 KB |
phy-s5pv210-usb2.c | -rw-r--r-- | 4.4 KB |
phy-samsung-usb2.c | -rw-r--r-- | 6.5 KB |
phy-samsung-usb2.h | -rw-r--r-- | 1.9 KB |
phy-spear1310-miphy.c | -rw-r--r-- | 7.6 KB |
phy-spear1340-miphy.c | -rw-r--r-- | 8.1 KB |
phy-stih407-usb.c | -rw-r--r-- | 4.8 KB |
phy-stih41x-usb.c | -rw-r--r-- | 4.7 KB |
phy-sun4i-usb.c | -rw-r--r-- | 20.0 KB |
phy-sun9i-usb.c | -rw-r--r-- | 5.0 KB |
phy-ti-pipe3.c | -rw-r--r-- | 17.5 KB |
phy-tusb1210.c | -rw-r--r-- | 3.5 KB |
phy-twl4030-usb.c | -rw-r--r-- | 21.6 KB |
phy-xgene.c | -rw-r--r-- | 59.8 KB |
ulpi_phy.h | -rw-r--r-- | 744 bytes |
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