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authorVlastimil Babka <vbabka@suse.cz>2016-07-28 15:49:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-28 16:07:41 -0700
commita5508cd83f10f663e05d212cb81f600a3af46e40 (patch)
treeb52a09bd0be8e756a48b6673c7746b3b0e1b6726 /mm/compaction.c
parent2516035499b9555f6acd373c9f12e44bcb50dbec (diff)
downloadlwn-a5508cd83f10f663e05d212cb81f600a3af46e40.tar.gz
lwn-a5508cd83f10f663e05d212cb81f600a3af46e40.zip
mm, compaction: introduce direct compaction priority
In the context of direct compaction, for some types of allocations we would like the compaction to either succeed or definitely fail while trying as hard as possible. Current async/sync_light migration mode is insufficient, as there are heuristics such as caching scanner positions, marking pageblocks as unsuitable or deferring compaction for a zone. At least the final compaction attempt should be able to override these heuristics. To communicate how hard compaction should try, we replace migration mode with a new enum compact_priority and change the relevant function signatures. In compact_zone_order() where struct compact_control is constructed, the priority is mapped to suitable control flags. This patch itself has no functional change, as the current priority levels are mapped back to the same migration modes as before. Expanding them will be done next. Note that !CONFIG_COMPACTION variant of try_to_compact_pages() is removed, as the only caller exists under CONFIG_COMPACTION. Link: http://lkml.kernel.org/r/20160721073614.24395-8-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/compaction.c')
-rw-r--r--mm/compaction.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/mm/compaction.c b/mm/compaction.c
index fee1118c8b94..4719a391242f 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1626,7 +1626,7 @@ out:
}
static enum compact_result compact_zone_order(struct zone *zone, int order,
- gfp_t gfp_mask, enum migrate_mode mode, int *contended,
+ gfp_t gfp_mask, enum compact_priority prio, int *contended,
unsigned int alloc_flags, int classzone_idx)
{
enum compact_result ret;
@@ -1636,7 +1636,8 @@ static enum compact_result compact_zone_order(struct zone *zone, int order,
.order = order,
.gfp_mask = gfp_mask,
.zone = zone,
- .mode = mode,
+ .mode = (prio == COMPACT_PRIO_ASYNC) ?
+ MIGRATE_ASYNC : MIGRATE_SYNC_LIGHT,
.alloc_flags = alloc_flags,
.classzone_idx = classzone_idx,
.direct_compaction = true,
@@ -1669,7 +1670,7 @@ int sysctl_extfrag_threshold = 500;
*/
enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
unsigned int alloc_flags, const struct alloc_context *ac,
- enum migrate_mode mode, int *contended)
+ enum compact_priority prio, int *contended)
{
int may_enter_fs = gfp_mask & __GFP_FS;
int may_perform_io = gfp_mask & __GFP_IO;
@@ -1684,7 +1685,7 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
if (!may_enter_fs || !may_perform_io)
return COMPACT_SKIPPED;
- trace_mm_compaction_try_to_compact_pages(order, gfp_mask, mode);
+ trace_mm_compaction_try_to_compact_pages(order, gfp_mask, prio);
/* Compact each zone in the list */
for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
@@ -1697,7 +1698,7 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
continue;
}
- status = compact_zone_order(zone, order, gfp_mask, mode,
+ status = compact_zone_order(zone, order, gfp_mask, prio,
&zone_contended, alloc_flags,
ac_classzone_idx(ac));
rc = max(status, rc);
@@ -1731,7 +1732,7 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
goto break_loop;
}
- if (mode != MIGRATE_ASYNC && (status == COMPACT_COMPLETE ||
+ if (prio != COMPACT_PRIO_ASYNC && (status == COMPACT_COMPLETE ||
status == COMPACT_PARTIAL_SKIPPED)) {
/*
* We think that allocation won't succeed in this zone