Re: [Patch] mm: Increase pagevec size on large system

2020-07-01 Thread Michal Hocko
On Tue 30-06-20 17:27:13, Andrew Morton wrote: > On Mon, 29 Jun 2020 09:57:42 -0700 Tim Chen > wrote: > > I am okay with Matthew's suggestion of keeping the stack pagevec size > > unchanged. > > Andrew, do you have a preference? > > > > I was assuming that for people who really care about savin

Re: [Patch] mm: Increase pagevec size on large system

2020-06-30 Thread Andrew Morton
On Mon, 29 Jun 2020 09:57:42 -0700 Tim Chen wrote: > > > I am okay with Matthew's suggestion of keeping the stack pagevec size > unchanged. > Andrew, do you have a preference? > > I was assuming that for people who really care about saving the kernel memory > usage, they would make CONFIG_NR_

Re: [Patch] mm: Increase pagevec size on large system

2020-06-29 Thread Tim Chen
On 6/26/20 8:47 PM, Andrew Morton wrote: > On Sat, 27 Jun 2020 04:13:04 +0100 Matthew Wilcox wrote: > >> On Fri, Jun 26, 2020 at 02:23:03PM -0700, Tim Chen wrote: >>> Enlarge the pagevec size to 31 to reduce LRU lock contention for >>> large systems. >>> >>> The LRU lock contention is reduced

Re: [Patch] mm: Increase pagevec size on large system

2020-06-26 Thread Andrew Morton
On Sat, 27 Jun 2020 04:13:04 +0100 Matthew Wilcox wrote: > On Fri, Jun 26, 2020 at 02:23:03PM -0700, Tim Chen wrote: > > Enlarge the pagevec size to 31 to reduce LRU lock contention for > > large systems. > > > > The LRU lock contention is reduced from 8.9% of total CPU cycles > > to 2.2% of CPU

Re: [Patch] mm: Increase pagevec size on large system

2020-06-26 Thread Matthew Wilcox
On Fri, Jun 26, 2020 at 02:23:03PM -0700, Tim Chen wrote: > Enlarge the pagevec size to 31 to reduce LRU lock contention for > large systems. > > The LRU lock contention is reduced from 8.9% of total CPU cycles > to 2.2% of CPU cyles. And the pmbench throughput increases > from 88.8 Mpages/sec to

[Patch] mm: Increase pagevec size on large system

2020-06-26 Thread Tim Chen
Pages to be added to a LRU are first cached in pagevec before being added to LRU in a batch via pagevec_lru_move_fn. By adding the pages in a batch with pagevec, the contention on LRU lock is mitigated. Currently the pagevec size is defined to be 15. We found during testing on a large SMT system