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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-09-11 04:34:46 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-09-11 04:34:46 -0300
commit863981e96738983919de841ec669e157e6bdaeb0 (patch)
treed6d89a12e7eb8017837c057935a2271290907f76 /include/linux/compaction.h
parent8dec7c70575785729a6a9e6719a955e9c545bcab (diff)
Linux-libre 4.7.1-gnupck-4.7.1-gnu
Diffstat (limited to 'include/linux/compaction.h')
-rw-r--r--include/linux/compaction.h151
1 files changed, 130 insertions, 21 deletions
diff --git a/include/linux/compaction.h b/include/linux/compaction.h
index d7c8de583..a58c852a2 100644
--- a/include/linux/compaction.h
+++ b/include/linux/compaction.h
@@ -2,21 +2,46 @@
#define _LINUX_COMPACTION_H
/* Return values for compact_zone() and try_to_compact_pages() */
-/* compaction didn't start as it was deferred due to past failures */
-#define COMPACT_DEFERRED 0
-/* compaction didn't start as it was not possible or direct reclaim was more suitable */
-#define COMPACT_SKIPPED 1
-/* compaction should continue to another pageblock */
-#define COMPACT_CONTINUE 2
-/* direct compaction partially compacted a zone and there are suitable pages */
-#define COMPACT_PARTIAL 3
-/* The full zone was compacted */
-#define COMPACT_COMPLETE 4
-/* For more detailed tracepoint output */
-#define COMPACT_NO_SUITABLE_PAGE 5
-#define COMPACT_NOT_SUITABLE_ZONE 6
-#define COMPACT_CONTENDED 7
/* When adding new states, please adjust include/trace/events/compaction.h */
+enum compact_result {
+ /* For more detailed tracepoint output - internal to compaction */
+ COMPACT_NOT_SUITABLE_ZONE,
+ /*
+ * compaction didn't start as it was not possible or direct reclaim
+ * was more suitable
+ */
+ COMPACT_SKIPPED,
+ /* compaction didn't start as it was deferred due to past failures */
+ COMPACT_DEFERRED,
+
+ /* compaction not active last round */
+ COMPACT_INACTIVE = COMPACT_DEFERRED,
+
+ /* For more detailed tracepoint output - internal to compaction */
+ COMPACT_NO_SUITABLE_PAGE,
+ /* compaction should continue to another pageblock */
+ COMPACT_CONTINUE,
+
+ /*
+ * The full zone was compacted scanned but wasn't successfull to compact
+ * suitable pages.
+ */
+ COMPACT_COMPLETE,
+ /*
+ * direct compaction has scanned part of the zone but wasn't successfull
+ * to compact suitable pages.
+ */
+ COMPACT_PARTIAL_SKIPPED,
+
+ /* compaction terminated prematurely due to lock contentions */
+ COMPACT_CONTENDED,
+
+ /*
+ * direct compaction partially compacted a zone and there might be
+ * suitable pages
+ */
+ COMPACT_PARTIAL,
+};
/* Used to signal whether compaction detected need_sched() or lock contention */
/* No contention detected */
@@ -38,13 +63,14 @@ extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
extern int sysctl_compact_unevictable_allowed;
extern int fragmentation_index(struct zone *zone, unsigned int order);
-extern unsigned long try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
- int alloc_flags, const struct alloc_context *ac,
- enum migrate_mode mode, int *contended);
+extern 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);
extern void compact_pgdat(pg_data_t *pgdat, int order);
extern void reset_isolation_suitable(pg_data_t *pgdat);
-extern unsigned long compaction_suitable(struct zone *zone, int order,
- int alloc_flags, int classzone_idx);
+extern enum compact_result compaction_suitable(struct zone *zone, int order,
+ unsigned int alloc_flags, int classzone_idx);
extern void defer_compaction(struct zone *zone, int order);
extern bool compaction_deferred(struct zone *zone, int order);
@@ -52,12 +78,80 @@ extern void compaction_defer_reset(struct zone *zone, int order,
bool alloc_success);
extern bool compaction_restarting(struct zone *zone, int order);
+/* Compaction has made some progress and retrying makes sense */
+static inline bool compaction_made_progress(enum compact_result result)
+{
+ /*
+ * Even though this might sound confusing this in fact tells us
+ * that the compaction successfully isolated and migrated some
+ * pageblocks.
+ */
+ if (result == COMPACT_PARTIAL)
+ return true;
+
+ return false;
+}
+
+/* Compaction has failed and it doesn't make much sense to keep retrying. */
+static inline bool compaction_failed(enum compact_result result)
+{
+ /* All zones were scanned completely and still not result. */
+ if (result == COMPACT_COMPLETE)
+ return true;
+
+ return false;
+}
+
+/*
+ * Compaction has backed off for some reason. It might be throttling or
+ * lock contention. Retrying is still worthwhile.
+ */
+static inline bool compaction_withdrawn(enum compact_result result)
+{
+ /*
+ * Compaction backed off due to watermark checks for order-0
+ * so the regular reclaim has to try harder and reclaim something.
+ */
+ if (result == COMPACT_SKIPPED)
+ return true;
+
+ /*
+ * If compaction is deferred for high-order allocations, it is
+ * because sync compaction recently failed. If this is the case
+ * and the caller requested a THP allocation, we do not want
+ * to heavily disrupt the system, so we fail the allocation
+ * instead of entering direct reclaim.
+ */
+ if (result == COMPACT_DEFERRED)
+ return true;
+
+ /*
+ * If compaction in async mode encounters contention or blocks higher
+ * priority task we back off early rather than cause stalls.
+ */
+ if (result == COMPACT_CONTENDED)
+ return true;
+
+ /*
+ * Page scanners have met but we haven't scanned full zones so this
+ * is a back off in fact.
+ */
+ if (result == COMPACT_PARTIAL_SKIPPED)
+ return true;
+
+ return false;
+}
+
+
+bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
+ int alloc_flags);
+
extern int kcompactd_run(int nid);
extern void kcompactd_stop(int nid);
extern void wakeup_kcompactd(pg_data_t *pgdat, int order, int classzone_idx);
#else
-static inline unsigned long try_to_compact_pages(gfp_t gfp_mask,
+static inline enum compact_result try_to_compact_pages(gfp_t gfp_mask,
unsigned int order, int alloc_flags,
const struct alloc_context *ac,
enum migrate_mode mode, int *contended)
@@ -73,7 +167,7 @@ static inline void reset_isolation_suitable(pg_data_t *pgdat)
{
}
-static inline unsigned long compaction_suitable(struct zone *zone, int order,
+static inline enum compact_result compaction_suitable(struct zone *zone, int order,
int alloc_flags, int classzone_idx)
{
return COMPACT_SKIPPED;
@@ -88,6 +182,21 @@ static inline bool compaction_deferred(struct zone *zone, int order)
return true;
}
+static inline bool compaction_made_progress(enum compact_result result)
+{
+ return false;
+}
+
+static inline bool compaction_failed(enum compact_result result)
+{
+ return false;
+}
+
+static inline bool compaction_withdrawn(enum compact_result result)
+{
+ return true;
+}
+
static inline int kcompactd_run(int nid)
{
return 0;