mm/page_alloc: adjust pcp->high after CPU hotplug events
The PCP high watermark is based on the number of online CPUs so the watermarks must be adjusted during CPU hotplug. At the time of hot-remove, the number of online CPUs is already adjusted but during hot-add, a delta needs to be applied to update PCP to the correct value. After this patch is applied, the high watermarks are adjusted correctly. # grep high: /proc/zoneinfo | tail -1 high: 649 # echo 0 > /sys/devices/system/cpu/cpu4/online # grep high: /proc/zoneinfo | tail -1 high: 664 # echo 1 > /sys/devices/system/cpu/cpu4/online # grep high: /proc/zoneinfo | tail -1 high: 649 Link: https://lkml.kernel.org/r/20210525080119.5455-4-mgorman@techsingularity.net Signed-off-by:Mel Gorman <mgorman@techsingularity.net> Acked-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Dave Hansen <dave.hansen@linux.intel.com> 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>
parent
b92ca18e
Please register or sign in to comment