Messages in this thread | | | Date | Thu, 19 Mar 2020 10:03:05 -0400 | From | Johannes Weiner <> | Subject | Re: [v4 PATCH 2/2] mm: swap: use smp_mb__after_atomic() to order LRU bit set |
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On Wed, Mar 18, 2020 at 11:02:21AM +0800, Yang Shi wrote: > Memory barrier is needed after setting LRU bit, but smp_mb() is too > strong. Some architectures, i.e. x86, imply memory barrier with atomic > operations, so replacing it with smp_mb__after_atomic() sounds better, > which is nop on strong ordered machines, and full memory barriers on > others. With this change the vm-scalability cases would perform better > on x86, I saw total 6% improvement with this patch and previous inline > fix. > > The test data (lru-file-readtwice throughput) against v5.6-rc4: > mainline w/ inline fix w/ both (adding this) > 150MB 154MB 159MB > > Fixes: 9c4e6b1a7027 ("mm, mlock, vmscan: no more skipping pagevecs") > Acked-by: Vlastimil Babka <vbabka@suse.cz> > Reviewed-and-Tested-by: Shakeel Butt <shakeelb@google.com> > Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
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