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Commit 1743660b authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds
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[PATCH] Zone reclaim: proc override 



proc support for zone reclaim

This patch creates a proc entry /proc/sys/vm/zone_reclaim_mode that may be
used to override the automatic determination of the zone reclaim made on
bootup.

Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 9eeff239

Documentation/sysctl/vm.txt

+18 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ Currently, these files are in /proc/sys/vm: 
- laptop_mode

- block_dump

- drop-caches

- zone_reclaim_mode



==============================================================
@@ -120,3 +121,20 @@ set to pcp->high/4. The upper limit of batch is (PAGE_SHIFT * 8) 


The initial value is zero.  Kernel does not use this value at boot time to set

the high water marks for each per cpu page list.



===============================================================



zone_reclaim_mode:



This is set during bootup to 1 if it is determined that pages from

remote zones will cause a significant performance reduction. The

page allocator will then reclaim easily reusable pages (those page

cache pages that are currently not used) before going off node.



The user can override this setting. It may be beneficial to switch

off zone reclaim if the system is used for a file server and all

of memory should be used for caching files from disk.



It may be beneficial to switch this on if one wants to do zone

reclaim regardless of the numa distances in the system.

include/linux/sysctl.h

+1 −0
Original line number Diff line number Diff line
@@ -182,6 +182,7 @@ enum 
	VM_SWAP_TOKEN_TIMEOUT=28, /* default time for token time out */

	VM_DROP_PAGECACHE=29,	/* int: nuke lots of pagecache */

	VM_PERCPU_PAGELIST_FRACTION=30,/* int: fraction of pages in each percpu_pagelist */

	VM_ZONE_RECLAIM_MODE=31,/* reclaim local zone memory before going off node */

};

kernel/sysctl.c

+11 −0
Original line number Diff line number Diff line
@@ -869,6 +869,17 @@ static ctl_table vm_table[] = { 
		.proc_handler	= &proc_dointvec_jiffies,

		.strategy	= &sysctl_jiffies,

	},

#endif

#ifdef CONFIG_NUMA

	{

		.ctl_name	= VM_ZONE_RECLAIM_MODE,

		.procname	= "zone_reclaim_mode",

		.data		= &zone_reclaim_mode,

		.maxlen		= sizeof(zone_reclaim_mode),

		.mode		= 0644,

		.proc_handler	= &proc_dointvec,

		.strategy	= &zero,

	},

#endif

	{ .ctl_name = 0 }

};