Subject: + mm-vmscan-do-not-throttle-based-on-pfmemalloc-reserves-if-node-has-no-zone_normal.patch added to -mm tree
To: mgorman@xxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 22 Apr 2014 12:32:03 -0700
The patch titled
Subject: mm: vmscan: do not throttle based on pfmemalloc reserves if node has no ZONE_NORMAL
has been added to the -mm tree. Its filename is
mm-vmscan-do-not-throttle-based-on-pfmemalloc-reserves-if-node-has-no-zone_normal.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-vmscan-do-not-throttle-based-on-pfmemalloc-reserves-if-node-has-no-zone_normal.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-vmscan-do-not-throttle-based-on-pfmemalloc-reserves-if-node-has-no-zone_normal.patch
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------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxx>
Subject: 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.
On a NUMA machine running a 32-bit kernel (I know) allocation requests
freom 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.
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 33 +++++++++++++++++++++++++++------
1 file changed, 27 insertions(+), 6 deletions(-)
diff -puN mm/vmscan.c~mm-vmscan-do-not-throttle-based-on-pfmemalloc-reserves-if-node-has-no-zone_normal mm/vmscan.c
--- a/mm/vmscan.c~mm-vmscan-do-not-throttle-based-on-pfmemalloc-reserves-if-node-has-no-zone_normal
+++ a/mm/vmscan.c
@@ -2522,10 +2522,17 @@ static bool pfmemalloc_watermark_ok(pg_d
for (i = 0; i <= ZONE_NORMAL; i++) {
zone = &pgdat->node_zones[i];
+ if (!populated_zone(zone))
+ continue;
+
pfmemalloc_reserve += min_wmark_pages(zone);
free_pages += zone_page_state(zone, NR_FREE_PAGES);
}
+ /* If there are no reserves (unexpected config) then do not throttle */
+ if (!pfmemalloc_reserve)
+ return true;
+
wmark_ok = free_pages > pfmemalloc_reserve / 2;
/* kswapd must be awake if processes are being throttled */
@@ -2550,9 +2557,9 @@ static bool pfmemalloc_watermark_ok(pg_d
static bool throttle_direct_reclaim(gfp_t gfp_mask, struct zonelist *zonelist,
nodemask_t *nodemask)
{
+ struct zoneref *z;
struct zone *zone;
- int high_zoneidx = gfp_zone(gfp_mask);
- pg_data_t *pgdat;
+ pg_data_t *pgdat = NULL;
/*
* Kernel threads should not be throttled as they may be indirectly
@@ -2571,10 +2578,24 @@ static bool throttle_direct_reclaim(gfp_
if (fatal_signal_pending(current))
goto out;
- /* Check if the pfmemalloc reserves are ok */
- first_zones_zonelist(zonelist, high_zoneidx, NULL, &zone);
- pgdat = zone->zone_pgdat;
- if (pfmemalloc_watermark_ok(pgdat))
+ /*
+ * Check if the pfmemalloc reserves are ok by finding the first node
+ * with a usable ZONE_NORMAL or lower zone
+ */
+ for_each_zone_zonelist_nodemask(zone, z, zonelist,
+ gfp_mask, nodemask) {
+ if (zone_idx(zone) > ZONE_NORMAL)
+ continue;
+
+ /* Throttle based on the first usable node */
+ pgdat = zone->zone_pgdat;
+ if (pfmemalloc_watermark_ok(pgdat))
+ goto out;
+ break;
+ }
+
+ /* If no zone was usable by the allocation flags then do not throttle */
+ if (!pgdat)
goto out;
/* Account for the throttling */
_
Patches currently in -mm which might be from mgorman@xxxxxxx are
hugetlb-ensure-hugepage-access-is-denied-if-hugepages-are-not-supported.patch
hugetlb-ensure-hugepage-access-is-denied-if-hugepages-are-not-supported-fix.patch
mm-compaction-make-isolate_freepages-start-at-pageblock-boundary.patch
x86-require-x86-64-for-automatic-numa-balancing.patch
x86-define-_page_numa-by-reusing-software-bits-on-the-pmd-and-pte-levels.patch
x86-define-_page_numa-by-reusing-software-bits-on-the-pmd-and-pte-levels-fix-2.patch
mm-introduce-do_shared_fault-and-drop-do_fault-fix-fix.patch
mm-compactionc-isolate_freepages_block-small-tuneup.patch
mm-only-force-scan-in-reclaim-when-none-of-the-lrus-are-big-enough.patch
mm-huge_memoryc-complete-conversion-to-pr_foo.patch
mm-disable-zone_reclaim_mode-by-default.patch
mm-page_alloc-do-not-cache-reclaim-distances.patch
mm-page_alloc-do-not-cache-reclaim-distances-fix.patch
mm-page_alloc-prevent-migrate_reserve-pages-from-being-misplaced.patch
mm-page_alloc-debug_vm-checks-for-free_list-placement-of-cma-and-reserve-pages.patch
mm-compaction-clean-up-unused-code-lines.patch
mm-compaction-cleanup-isolate_freepages.patch
mm-compaction-cleanup-isolate_freepages-fix.patch
mm-swapc-clean-up-lru_cache_add-functions.patch
mm-vmscan-do-not-throttle-based-on-pfmemalloc-reserves-if-node-has-no-zone_normal.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
linux-next.patch
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