mm: compaction: encapsulate defer reset logic

commit de6c60a6c115acaa721cfd499e028a413d1fcbf3 upstream.

Currently there are several functions to manipulate the deferred
compaction state variables.  The remaining case where the variables are
touched directly is when a successful allocation occurs in direct
compaction, or is expected to be successful in the future by kswapd.
Here, the lowest order that is expected to fail is updated, and in the
case of successful allocation, the deferred status and counter is reset
completely.

Create a new function compaction_defer_reset() to encapsulate this
functionality and make it easier to understand the code.  No functional
change.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/include/linux/compaction.h b/include/linux/compaction.h
index 091d72e70d8a708f55d447b8559814caa2952b1a..7e1c76e3cd6890387b983be96377bf7c19cd3c06 100644 (file)
--- a/include/linux/compaction.h
+++ b/include/linux/compaction.h
@@ -62,6 +62,22 @@ static inline bool compaction_deferred(struct zone *zone, int order)
        return zone->compact_considered < defer_limit;
 }
 
+/*
+ * Update defer tracking counters after successful compaction of given order,
+ * which means an allocation either succeeded (alloc_success == true) or is
+ * expected to succeed.
+ */
+static inline void compaction_defer_reset(struct zone *zone, int order,
+               bool alloc_success)
+{
+       if (alloc_success) {
+               zone->compact_considered = 0;
+               zone->compact_defer_shift = 0;
+       }
+       if (order >= zone->compact_order_failed)
+               zone->compact_order_failed = order + 1;
+}
+
 /* Returns true if restarting compaction after many failures */
 static inline bool compaction_restarting(struct zone *zone, int order)
 {

diff --git a/mm/compaction.c b/mm/compaction.c
index d656656903344004d9742b5f19e337482a4ad1fe..c55bd45cf6e20da6e2ad1e521c44b22c3aff5e26 100644 (file)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1144,12 +1144,11 @@ static void __compact_pgdat(pg_data_t *pgdat, struct compact_control *cc)
                        compact_zone(zone, cc);
 
                if (cc->order > 0) {
-                       int ok = zone_watermark_ok(zone, cc->order,
-                                               low_wmark_pages(zone), 0, 0);
-                       if (ok && cc->order >= zone->compact_order_failed)
-                               zone->compact_order_failed = cc->order + 1;
+                       if (zone_watermark_ok(zone, cc->order,
+                                               low_wmark_pages(zone), 0, 0))
+                               compaction_defer_reset(zone, cc->order, false);
                        /* Currently async compaction is never deferred. */
-                       else if (!ok && cc->sync)
+                       else if (cc->sync)
                                defer_compaction(zone, cc->order);
                }
 

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index baef87ec4cf01904a8d65f0151c0ed365ef31b03..3078eafbba86b78e7e918cfabceb580757dd4156 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2251,10 +2251,7 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
                                preferred_zone, migratetype);
                if (page) {
                        preferred_zone->compact_blockskip_flush = false;
-                       preferred_zone->compact_considered = 0;
-                       preferred_zone->compact_defer_shift = 0;
-                       if (order >= preferred_zone->compact_order_failed)
-                               preferred_zone->compact_order_failed = order + 1;
+                       compaction_defer_reset(preferred_zone, order, true);
                        count_vm_event(COMPACTSUCCESS);
                        return page;
                }