COMPACT_PARTIAL has historically meant that compaction returned after doing
some work without fully compacting a zone. It however didn't distinguish if
compaction terminated because it succeeded in creating the requested high-order
page. This has changed recently and now we only return COMPACT_PARTIAL when
compaction thinks it succeeded, or the high-order watermark check in
compaction_suitable() passes and no compaction needs to be done.
So at this point we can make the return value clearer by renaming it to
COMPACT_SUCCESS. The next patch will remove some redundant tests for success
where compaction just returned COMPACT_SUCCESS.
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
---
include/linux/compaction.h | 8 ++++----
include/trace/events/compaction.h | 2 +-
mm/compaction.c | 12 ++++++------
mm/vmscan.c | 2 +-
4 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/include/linux/compaction.h b/include/linux/compaction.h
index 1bb58581301c..e88c037afe47 100644
--- a/include/linux/compaction.h
+++ b/include/linux/compaction.h
@@ -49,10 +49,10 @@ enum compact_result {
COMPACT_CONTENDED,
/*
- * direct compaction partially compacted a zone and there might be
- * suitable pages
+ * direct compaction terminated after concluding that the allocation
+ * should now succeed
*/
- COMPACT_PARTIAL,
+ COMPACT_SUCCESS,
};
struct alloc_context; /* in mm/internal.h */
@@ -88,7 +88,7 @@ static inline bool compaction_made_progress(enum compact_result result)
* that the compaction successfully isolated and migrated some
* pageblocks.
*/
- if (result == COMPACT_PARTIAL)
+ if (result == COMPACT_SUCCESS)
return true;
return false;
diff --git a/include/trace/events/compaction.h b/include/trace/events/compaction.h
index c2ba402ab256..cbdb90b6b308 100644
--- a/include/trace/events/compaction.h
+++ b/include/trace/events/compaction.h
@@ -13,7 +13,7 @@
EM( COMPACT_SKIPPED, "skipped") \
EM( COMPACT_DEFERRED, "deferred") \
EM( COMPACT_CONTINUE, "continue") \
- EM( COMPACT_PARTIAL, "partial") \
+ EM( COMPACT_SUCCESS, "success") \
EM( COMPACT_PARTIAL_SKIPPED, "partial_skipped") \
EM( COMPACT_COMPLETE, "complete") \
EM( COMPACT_NO_SUITABLE_PAGE, "no_suitable_page") \
diff --git a/mm/compaction.c b/mm/compaction.c
index 328bdfeece2d..c355bf0d8599 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1329,13 +1329,13 @@ static enum compact_result __compact_finished(struct zone *zone, struct compact_
/* Job done if page is free of the right migratetype */
if (!list_empty(&area->free_list[migratetype]))
- return COMPACT_PARTIAL;
+ return COMPACT_SUCCESS;
#ifdef CONFIG_CMA
/* MIGRATE_MOVABLE can fallback on MIGRATE_CMA */
if (migratetype == MIGRATE_MOVABLE &&
!list_empty(&area->free_list[MIGRATE_CMA]))
- return COMPACT_PARTIAL;
+ return COMPACT_SUCCESS;
#endif
/*
* Job done if allocation would steal freepages from
@@ -1343,7 +1343,7 @@ static enum compact_result __compact_finished(struct zone *zone, struct compact_
*/
if (find_suitable_fallback(area, order, migratetype,
true, &can_steal) != -1)
- return COMPACT_PARTIAL;
+ return COMPACT_SUCCESS;
}
return COMPACT_NO_SUITABLE_PAGE;
@@ -1367,7 +1367,7 @@ static enum compact_result compact_finished(struct zone *zone,
* compaction_suitable: Is this suitable to run compaction on this zone now?
* Returns
* COMPACT_SKIPPED - If there are too few free pages for compaction
- * COMPACT_PARTIAL - If the allocation would succeed without compaction
+ * COMPACT_SUCCESS - If the allocation would succeed without compaction
* COMPACT_CONTINUE - If compaction should run now
*/
static enum compact_result __compaction_suitable(struct zone *zone, int order,
@@ -1388,7 +1388,7 @@ static enum compact_result __compaction_suitable(struct zone *zone, int order,
*/
if (zone_watermark_ok(zone, order, watermark, classzone_idx,
alloc_flags))
- return COMPACT_PARTIAL;
+ return COMPACT_SUCCESS;
/*
* Watermarks for order-0 must be met for compaction. Note the 2UL.
@@ -1477,7 +1477,7 @@ static enum compact_result compact_zone(struct zone *zone, struct compact_contro
ret = compaction_suitable(zone, cc->order, cc->alloc_flags,
cc->classzone_idx);
/* Compaction is likely to fail */
- if (ret == COMPACT_PARTIAL || ret == COMPACT_SKIPPED)
+ if (ret == COMPACT_SUCCESS || ret == COMPACT_SKIPPED)
return ret;
/* huh, compaction_suitable is returning something unexpected */
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 374d95d04178..c84784765d3a 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2514,7 +2514,7 @@ static inline bool should_continue_reclaim(struct pglist_data *pgdat,
continue;
switch (compaction_suitable(zone, sc->order, 0, sc->reclaim_idx)) {
- case COMPACT_PARTIAL:
+ case COMPACT_SUCCESS:
case COMPACT_CONTINUE:
return false;
default:
--
2.9.2
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>