diff options
| 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 /include | |
| parent | c49c2c47dab6b8d45022b3fabf0642a0e62e3109 (diff) | |
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 'include')
| -rw-r--r-- | include/linux/mmzone.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index b2f40d64bc4b..7d206ca850c7 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1029,12 +1029,15 @@ int watermark_scale_factor_sysctl_handler(struct ctl_table *, int, void *, extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES]; int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, void *, size_t *, loff_t *); +int percpu_pagelist_high_fraction_sysctl_handler(struct ctl_table *, int, + void *, size_t *, loff_t *); int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int, void *, size_t *, loff_t *); int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int, void *, size_t *, loff_t *); int numa_zonelist_order_handler(struct ctl_table *, int, void *, size_t *, loff_t *); +extern int percpu_pagelist_high_fraction; extern char numa_zonelist_order[]; #define NUMA_ZONELIST_ORDER_LEN 16 |