@@ -2277,6 +2277,19 @@ static void age_active_anon(struct zone *zone, struct scan_control *sc)
} while (memcg);
}
+static bool zone_balanced(struct zone *zone, int order,
+ unsigned long balance_gap, int classzone_idx)
+{
+ if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone) +
+ balance_gap, classzone_idx, 0))
+ return false;
+
+ if (COMPACTION_BUILD && order && !compaction_suitable(zone, order))
+ return false;
+
+ return true;
+}
+
/*
* pgdat_balanced is used when checking if a node is balanced for high-order
* allocations. Only zones that meet watermarks and are in a zone allowed
@@ -2336,8 +2349,7 @@ static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining,
continue;
}
- if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone),
- i, 0))
+ if (!zone_balanced(zone, order, 0, i))
all_zones_ok = false;
else
balanced += zone->present_pages;
@@ -2446,8 +2458,7 @@ loop_again:
break;
}
- if (!zone_watermark_ok_safe(zone, order,
- high_wmark_pages(zone), 0, 0)) {
+ if (!zone_balanced(zone, order, 0, 0)) {
end_zone = i;
break;
} else {
@@ -2523,9 +2534,8 @@ loop_again:
testorder = 0;
if ((buffer_heads_over_limit && is_highmem_idx(i)) ||
- !zone_watermark_ok_safe(zone, testorder,
- high_wmark_pages(zone) + balance_gap,
- end_zone, 0)) {
+ !zone_balanced(zone, testorder,
+ balance_gap, end_zone)) {
shrink_zone(zone, &sc);
reclaim_state->reclaimed_slab = 0;
@@ -2552,8 +2562,7 @@ loop_again:
continue;
}
- if (!zone_watermark_ok_safe(zone, testorder,
- high_wmark_pages(zone), end_zone, 0)) {
+ if (!zone_balanced(zone, testorder, 0, end_zone)) {
all_zones_ok = 0;
/*
* We are still under min water mark. This
This is a note to let you know that I have just added a patch titled mm: vmscan: fix endless loop in kswapd balancing to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Herton ------ From e878bc2769bf1d5d690406bc0713789c89d68b2a Mon Sep 17 00:00:00 2001 From: Johannes Weiner <hannes@cmpxchg.org> Date: Thu, 29 Nov 2012 13:54:23 -0800 Subject: [PATCH] mm: vmscan: fix endless loop in kswapd balancing commit 60cefed485a02bd99b6299dad70666fe49245da7 upstream. Kswapd does not in all places have the same criteria for a balanced zone. Zones are only being reclaimed when their high watermark is breached, but compaction checks loop over the zonelist again when the zone does not meet the low watermark plus two times the size of the allocation. This gets kswapd stuck in an endless loop over a small zone, like the DMA zone, where the high watermark is smaller than the compaction requirement. Add a function, zone_balanced(), that checks the watermark, and, for higher order allocations, if compaction has enough free memory. Then use it uniformly to check for balanced zones. This makes sure that when the compaction watermark is not met, at least reclaim happens and progress is made - or the zone is declared unreclaimable at some point and skipped entirely. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: George Spelvin <linux@horizon.com> Reported-by: Johannes Hirte <johannes.hirte@fem.tu-ilmenau.de> Reported-by: Tomas Racek <tracek@redhat.com> Tested-by: Johannes Hirte <johannes.hirte@fem.tu-ilmenau.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> --- mm/vmscan.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) -- 1.7.9.5