https://github.com/torvalds/linux
Revision 42f930da7f00c0ab23df4c7aed36137f35988980 authored by Don Zickus on 01 November 2017, 18:11:27 UTC, committed by Thomas Gleixner on 01 November 2017, 20:18:40 UTC
Guenter reported: There is still a problem. When running echo 6 > /proc/sys/kernel/watchdog_thresh echo 5 > /proc/sys/kernel/watchdog_thresh repeatedly, the message NMI watchdog: Enabled. Permanently consumes one hw-PMU counter. stops after a while (after ~10-30 iterations, with fluctuations). Maybe watchdog_cpus needs to be atomic ? That's correct as this again is affected by the asynchronous nature of the smpboot thread unpark mechanism. CPU 0 CPU1 CPU2 write(watchdog_thresh, 6) stop() park() update() start() unpark() thread->unpark() cnt++; write(watchdog_thresh, 5) thread->unpark() stop() park() thread->park() cnt--; cnt++; update() start() unpark() That's not a functional problem, it just affects the informational message. Convert watchdog_cpus to atomic_t to prevent the problem Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lkml.kernel.org/r/20171101181126.j727fqjmdthjz4xk@redhat.com
1 parent 9c388a5
Tip revision: 42f930da7f00c0ab23df4c7aed36137f35988980 authored by Don Zickus on 01 November 2017, 18:11:27 UTC
watchdog/hardlockup/perf: Use atomics to track in-use cpu counter
watchdog/hardlockup/perf: Use atomics to track in-use cpu counter
Tip revision: 42f930d
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arch | ||
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certs | ||
crypto | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.cocciconfig | -rw-r--r-- | 59 bytes |
.get_maintainer.ignore | -rw-r--r-- | 31 bytes |
.gitattributes | -rw-r--r-- | 30 bytes |
.gitignore | -rw-r--r-- | 1.3 KB |
.mailmap | -rw-r--r-- | 8.2 KB |
COPYING | -rw-r--r-- | 18.3 KB |
CREDITS | -rw-r--r-- | 96.1 KB |
Kbuild | -rw-r--r-- | 2.2 KB |
Kconfig | -rw-r--r-- | 252 bytes |
MAINTAINERS | -rw-r--r-- | 420.4 KB |
Makefile | -rw-r--r-- | 58.4 KB |
README | -rw-r--r-- | 722 bytes |
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