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author | 2010-02-18 12:29:23 +0000 | |
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committer | 2010-04-07 18:00:47 +1000 | |
commit | 27f10907b7cca57df5e2a9c94c14354dd1b7879d (patch) | |
tree | 4e334ef517c44c02e0645ccc792d285060ba55b0 /arch/powerpc/include/asm | |
parent | powerpc/pmac: Fix dangling pointers (diff) | |
download | linux-dev-27f10907b7cca57df5e2a9c94c14354dd1b7879d.tar.xz linux-dev-27f10907b7cca57df5e2a9c94c14354dd1b7879d.zip |
powerpc/numa: Set a smaller value for RECLAIM_DISTANCE to enable zone reclaim
I noticed /proc/sys/vm/zone_reclaim_mode was 0 on a ppc64 NUMA box. It gets
enabled via this:
/*
* If another node is sufficiently far away then it is better
* to reclaim pages in a zone before going off node.
*/
if (distance > RECLAIM_DISTANCE)
zone_reclaim_mode = 1;
Since we use the default value of 20 for REMOTE_DISTANCE and 20 for
RECLAIM_DISTANCE it never kicks in.
The local to remote bandwidth ratios can be quite large on System p
machines so it makes sense for us to reclaim clean pagecache locally before
going off node.
The patch below sets a smaller value for RECLAIM_DISTANCE and thus enables
zone reclaim.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/include/asm')
-rw-r--r-- | arch/powerpc/include/asm/topology.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h index 8eaec310a25b..a7d769491555 100644 --- a/arch/powerpc/include/asm/topology.h +++ b/arch/powerpc/include/asm/topology.h @@ -8,6 +8,16 @@ struct device_node; #ifdef CONFIG_NUMA +/* + * Before going off node we want the VM to try and reclaim from the local + * node. It does this if the remote distance is larger than RECLAIM_DISTANCE. + * With the default REMOTE_DISTANCE of 20 and the default RECLAIM_DISTANCE of + * 20, we never reclaim and go off node straight away. + * + * To fix this we choose a smaller value of RECLAIM_DISTANCE. + */ +#define RECLAIM_DISTANCE 10 + #include <asm/mmzone.h> static inline int cpu_to_node(int cpu) |