Messages in this thread | | | Date | Mon, 26 Jan 2009 14:16:05 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH 2/3] work_on_cpu: Use our own workqueue. |
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On Mon, 26 Jan 2009 23:05:37 +0100 Ingo Molnar <mingo@elte.hu> wrote:
> > * Andrew Morton <akpm@linux-foundation.org> wrote: > > > Well it turns out that I was having a less-than-usually-senile moment: > > > > : implement flush_work() > > > Why isn't that working in this case?? > > how would that work in this case? We defer processing into the workqueue > exactly because we want its per-CPU properties.
It detaches the work item, moves it to head-of-queue, reinserts it then waits on it. I think.
This might have a race+hole. If a currently-running "unrelated" work item tries to take the lock which the flush_work() caller is holding then there's no way in which keventd will come back to execute the work item which we just put on the head of queue.
> We want work_on_cpu() to > be done in the workqueue context on the CPUs that were specified, not in > the local CPU context.
flush_work() is supposed to work in the way which you describe.
But Oleg's "we may be running on a different CPU" comment has me all confused.
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