Messages in this thread | | | Date | Tue, 20 Nov 2007 19:53:08 -0500 | From | Mathieu Desnoyers <> | Subject | Re: [rfc 19/45] cpu alloc: NFS statistics |
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* Trond Myklebust (trond.myklebust@fys.uio.no) wrote: > > On Tue, 2007-11-20 at 16:50 -0500, Mathieu Desnoyers wrote: > > Then my original point is valid : put_no_resched() will cause unwanted > > scheduler latencies. It's designed only to be used from within the > > scheduler code itself. The correct approach would be a standard > > put_cpu(). > > > > Or am I missing something ? > > Then someone who cares about scheduler latency had better audit the code > and figure out which calls are made under spinlock, and which aren't: > it's not on my personal list of high priorities. I'll be happy to review > any patches, though. >
put_cpu() will work flawlessly when nested within a spinlock. the spinlock disabled itself preemption, and a nested preemption disable/enable/check will end up incrementing/decrementing the preempt cours. The check at the end will just not call the scheduler when nested within a spinlock.
If this is what you are worried about, then you shouldn't. I am a bit surprised about your reaction though.. so I probably missed something/don't understand correctly your fear about check_resched within a spinlock.
Mathieu
-- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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