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Jeremy Fitzhardinge
966812dc98
The softlockup watchdog is currently a nuisance in a virtual machine, since the whole system could have the CPU stolen from it for a long period of time. While it would be unlikely for a guest domain to be denied timer interrupts for over 10s, it could happen and any softlockup message would be completely spurious. Earlier I proposed that sched_clock() return time in unstolen nanoseconds, which is how Xen and VMI currently implement it. If the softlockup watchdog uses sched_clock() to measure time, it would automatically ignore stolen time, and therefore only report when the guest itself locked up. When running native, sched_clock() returns real-time nanoseconds, so the behaviour would be unchanged. Note that sched_clock() used this way is inherently per-cpu, so this patch makes sure that the per-processor watchdog thread initialized its own timestamp. Signed-off-by: Jeremy Fitzhardinge <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: john stultz <[email protected]> Cc: Zachary Amsden <[email protected]> Cc: James Morris <[email protected]> Cc: Dan Hecht <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Martin Schwidefsky <[email protected]> Cc: Prarit Bhargava <[email protected]> Cc: Chris Lalancette <[email protected]> Cc: Rick Lindsley <[email protected]> Cc: Eric Dumazet <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>