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author | Mel Gorman <mgorman@suse.de> | 2014-06-04 16:07:35 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-06-04 16:54:01 -0700 |
commit | 675becce15f320337499bc1a9356260409a5ba29 (patch) | |
tree | cfd83d7630aff3cee016910afff4d663e8ba3c33 /arch/mips | |
parent | f98bafa06a28fdfdd5c49f820f4d6560f636fc46 (diff) | |
download | op-kernel-dev-675becce15f320337499bc1a9356260409a5ba29.zip op-kernel-dev-675becce15f320337499bc1a9356260409a5ba29.tar.gz |
mm: vmscan: do not throttle based on pfmemalloc reserves if node has no ZONE_NORMAL
throttle_direct_reclaim() is meant to trigger during swap-over-network
during which the min watermark is treated as a pfmemalloc reserve. It
throttes on the first node in the zonelist but this is flawed.
The user-visible impact is that a process running on CPU whose local
memory node has no ZONE_NORMAL will stall for prolonged periods of time,
possibly indefintely. This is due to throttle_direct_reclaim thinking the
pfmemalloc reserves are depleted when in fact they don't exist on that
node.
On a NUMA machine running a 32-bit kernel (I know) allocation requests
from CPUs on node 1 would detect no pfmemalloc reserves and the process
gets throttled. This patch adjusts throttling of direct reclaim to
throttle based on the first node in the zonelist that has a usable
ZONE_NORMAL or lower zone.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/mips')
0 files changed, 0 insertions, 0 deletions