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authorMel Gorman <mgorman@techsingularity.net>2016-09-01 16:14:55 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-09-01 17:52:01 -0700
commit6aa303defb7454a2520c4ddcdf6b081f62a15890 (patch)
treef29799a63374ed8b39114c8f55bc10f52b679737 /mm/page_alloc.c
parente6173ba42bbdba05fd4f3021c0beda0506271507 (diff)
mm, vmscan: only allocate and reclaim from zones with pages managed by the buddy allocator
Firmware Assisted Dump (FA_DUMP) on ppc64 reserves substantial amounts of memory when booting a secondary kernel. Srikar Dronamraju reported that multiple nodes may have no memory managed by the buddy allocator but still return true for populated_zone(). Commit 1d82de618ddd ("mm, vmscan: make kswapd reclaim in terms of nodes") was reported to cause kswapd to spin at 100% CPU usage when fadump was enabled. The old code happened to deal with the situation of a populated node with zero free pages by co-incidence but the current code tries to reclaim populated zones without realising that is impossible. We cannot just convert populated_zone() as many existing users really need to check for present_pages. This patch introduces a managed_zone() helper and uses it in the few cases where it is critical that the check is made for managed pages -- zonelist construction and page reclaim. Link: http://lkml.kernel.org/r/20160831195104.GB8119@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Tested-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7791a03f8deb..a2214c64ed3c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4360,7 +4360,7 @@ static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
do {
zone_type--;
zone = pgdat->node_zones + zone_type;
- if (populated_zone(zone)) {
+ if (managed_zone(zone)) {
zoneref_set_zone(zone,
&zonelist->_zonerefs[nr_zones++]);
check_highest_zone(zone_type);
@@ -4598,7 +4598,7 @@ static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
for (j = 0; j < nr_nodes; j++) {
node = node_order[j];
z = &NODE_DATA(node)->node_zones[zone_type];
- if (populated_zone(z)) {
+ if (managed_zone(z)) {
zoneref_set_zone(z,
&zonelist->_zonerefs[pos++]);
check_highest_zone(zone_type);