Messages in this thread | | | Subject | Re: [PATCH] khungtaskd: Kick stuck processes | From | Tetsuo Handa <> | Date | Fri, 9 Feb 2018 20:30:41 +0900 |
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Chris Wilson wrote: > Quoting Tetsuo Handa (2018-02-08 23:10:43) > > Chris Wilson wrote: > > > After spotting a stuck process, and having decided not to panic, give > > > the task a kick to see if that helps it to recover (e.g. to paper over a > > > missed wake up). > > > > Yes, we are seeing hangs at io_schedule(), but doesn't optionally allowing > > io_schedule() be replaced with timeout version (e.g. dump_page() upon timeout > > if io_schedule() was called for e.g. wait_on_page_bit()) give us more clue? > > Yes, this isn't for debugging who left the page locked (or the exact > root cause), this is just trying to allow the system to limp along > afterwards :) From personal experience, I know how easy it is to lose a > wakeup and the only thing to notice is khungtaskd shouting every 120s.
Calling wake_up_process() does not sleep, does it? Then, I think you can do it using SystemTap, for SystemTap gives you ability to call exported functions at (almost) arbitrary line of (almost) arbitrary file. You can find https://events.static.linuxfound.org/sites/events/files/slides/LCJ2014-en_0.pdf for an example.
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