Messages in this thread | | | Date | Mon, 25 May 2020 17:45:05 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v1 02/25] mm/swap: Don't abuse the seqcount latching API |
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On Mon, May 25, 2020 at 05:24:01PM +0200, Ahmed S. Darwish wrote: > Peter Zijlstra <peterz@infradead.org> wrote: > > On Tue, May 19, 2020 at 11:45:24PM +0200, Ahmed S. Darwish wrote:
> > > + WRITE_ONCE(lru_drain_gen, lru_drain_gen + 1); > > > + smp_wmb(); > > > > You can leave this smp_wmb() out and rely on the smp_mb() implied by > > queue_work_on()'s test_and_set_bit(). > > > > Won't this be too implicit? > > Isn't it possible that, over the years, queue_work_on() impementation > changes and the test_and_set_bit()/smp_mb() gets removed? > > If that happens, this commit will get *silently* broken and the local > CPU pages won't be drained.
Add a comment to queue_work_on() that points here? That way people are aware.
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