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| author | Mel Gorman <mgorman@techsingularity.net> | 2021-06-28 19:42:24 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-06-29 10:53:55 -0700 |
| commit | 74f44822097c665041010994502b5971d6cd9f04 (patch) | |
| tree | 308a8f1e7f8087b1f39ea0bc87813ae7c5519186 /kernel/sysctl.c | |
| parent | c49c2c47dab6b8d45022b3fabf0642a0e62e3109 (diff) | |
| download | lwn-74f44822097c665041010994502b5971d6cd9f04.tar.gz lwn-74f44822097c665041010994502b5971d6cd9f04.zip | |
mm/page_alloc: introduce vm.percpu_pagelist_high_fraction
This introduces a new sysctl vm.percpu_pagelist_high_fraction. It is
similar to the old vm.percpu_pagelist_fraction. The old sysctl increased
both pcp->batch and pcp->high with the higher pcp->high potentially
reducing zone->lock contention. However, the higher pcp->batch value also
potentially increased allocation latency while the PCP was refilled. This
sysctl only adjusts pcp->high so that zone->lock contention is potentially
reduced but allocation latency during a PCP refill remains the same.
# grep -E "high:|batch" /proc/zoneinfo | tail -2
high: 649
batch: 63
# sysctl vm.percpu_pagelist_high_fraction=8
# grep -E "high:|batch" /proc/zoneinfo | tail -2
high: 35071
batch: 63
# sysctl vm.percpu_pagelist_high_fraction=64
high: 4383
batch: 63
# sysctl vm.percpu_pagelist_high_fraction=0
high: 649
batch: 63
[mgorman@techsingularity.net: fix documentation]
Link: https://lkml.kernel.org/r/20210528151010.GQ30378@techsingularity.net
Link: https://lkml.kernel.org/r/20210525080119.5455-7-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/sysctl.c')
| -rw-r--r-- | kernel/sysctl.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 51213c33171e..69d925f1e5da 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -2909,6 +2909,14 @@ static struct ctl_table vm_table[] = { .extra2 = &one_thousand, }, { + .procname = "percpu_pagelist_high_fraction", + .data = &percpu_pagelist_high_fraction, + .maxlen = sizeof(percpu_pagelist_high_fraction), + .mode = 0644, + .proc_handler = percpu_pagelist_high_fraction_sysctl_handler, + .extra1 = SYSCTL_ZERO, + }, + { .procname = "page_lock_unfairness", .data = &sysctl_page_lock_unfairness, .maxlen = sizeof(sysctl_page_lock_unfairness), |