On Thu, Jan 25, 2018 at 03:21:44PM +0800, Aaron Lu wrote: > When freeing a batch of pages from Per-CPU-Pages(PCP) back to buddy, > the zone->lock is held and then pages are chosen from PCP's migratetype > list. While there is actually no need to do this 'choose part' under > lock since it's PCP pages, the only CPU that can touch them is us and > irq is also disabled. > > Moving this part outside could reduce lock held time and improve > performance. Test with will-it-scale/page_fault1 full load: > > kernel Broadwell(2S) Skylake(2S) Broadwell(4S) Skylake(4S) > v4.15-rc4 9037332 8000124 13642741 15728686 > this patch 9608786 +6.3% 8368915 +4.6% 14042169 +2.9% 17433559 +10.8% > > What the test does is: starts $nr_cpu processes and each will repeatedly > do the following for 5 minutes: > 1 mmap 128M anonymouse space; > 2 write access to that space; > 3 munmap. > The score is the aggregated iteration. > > https://github.com/antonblanchard/will-it-scale/blob/master/tests/page_fault1.c > > Acked-by: Mel Gorman <mgor...@techsingularity.net> > Signed-off-by: Aaron Lu <aaron...@intel.com>
It looks like this series may have gotten lost because it was embedded within an existing thread or else it was the proximity to the merge window. I suggest a rebase, retest and resubmit unless there was some major objection that I missed. Patch 1 is fine by me at least. I never explicitly acked patch 2 but I've no major objection to it, just am a tad uncomfortable with prefetch magic sauce in general. -- Mel Gorman SUSE Labs
