diff options
| author | Mel Gorman <mgorman@techsingularity.net> | 2016-09-01 16:14:55 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-09-01 17:52:01 -0700 |
| commit | 6aa303defb7454a2520c4ddcdf6b081f62a15890 (patch) | |
| tree | f29799a63374ed8b39114c8f55bc10f52b679737 /mm/page_alloc.c | |
| parent | e6173ba42bbdba05fd4f3021c0beda0506271507 (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.c | 4 |
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); |