diff options
| author | Mel Gorman <mgorman@suse.de> | 2014-04-23 08:27:22 +1000 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2014-04-23 08:27:22 +1000 |
| commit | 1fa42355f92ca044bc6904a47c1b041402de9321 (patch) | |
| tree | 3519c203710251da50f64575db98418a5a4aee29 /mm | |
| parent | fac31ddf18d40aba9560bbbb8a26d879c6fbcd65 (diff) | |
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@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/vmscan.c | 33 |
1 files changed, 27 insertions, 6 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 37f4baec1e30..c250fee1db3c 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2522,10 +2522,17 @@ static bool pfmemalloc_watermark_ok(pg_data_t *pgdat) 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_data_t *pgdat) 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_t gfp_mask, struct zonelist *zonelist, 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 */ |