Messages in this thread | | | Date | Tue, 25 Oct 2022 15:55:09 -0400 | Subject | Re: [PATCH v3 2/5] locking/rwsem: Limit # of null owner retries for handoff writer | From | Waiman Long <> |
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On 10/25/22 07:48, Peter Zijlstra wrote: > On Tue, Oct 25, 2022 at 01:22:22PM +0200, Peter Zijlstra wrote: > >> Funny, I find the former approach much saner. Disabling preemption >> around the whole thing fixes the fundamental problem while spin-limiting >> is a band-aid. >> >> Note how rwsem_write_trylock() already does preempt_disable(), having >> the read-side do something similar only makes sense. > Something like the completely untested below perhaps...
That is quite a number of changes spread over many different functions. That is the kind of changes that may make it harder to backport to stable releases.
This patch is just a stop-gap measure for stable releases which I essentially revert in a later patch. I have no objection to disable preemption in within the rwsem code exception to be backported to a stable release. So I can add another patch on top of the series to essentially do that.
Cheers, Longman
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