mm: avoid taking zone lock in pagetypeinfo_showmixed()

pagetypeinfo_showmixedcount_print is found to take a lot of time to
complete and it does this holding the zone lock and disabling
interrupts.  In some cases it is found to take more than a second (On a
2.4GHz,8Gb RAM,arm64 cpu).

Avoid taking the zone lock similar to what is done by read_page_owner,
which means possibility of inaccurate results.

Link: http://lkml.kernel.org/r/1498045643-12257-1-git-send-email-vinmenon@codeaurora.org
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: zhongjiang <zhongjiang@huawei.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/page_owner.c b/mm/page_owner.c
index 60634dc53a885debd78878692f806c93883cbfff..0fd9dcf2c5dc158789831e0309d1fa66968b9205 100644 (file)
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -281,7 +281,11 @@ void pagetypeinfo_showmixedcount_print(struct seq_file *m,
                                continue;
 
                        if (PageBuddy(page)) {
-                               pfn += (1UL << page_order(page)) - 1;
+                               unsigned long freepage_order;
+
+                               freepage_order = page_order_unsafe(page);
+                               if (freepage_order < MAX_ORDER)
+                                       pfn += (1UL << freepage_order) - 1;
                                continue;
                        }
 

diff --git a/mm/vmstat.c b/mm/vmstat.c
index 744ceaeb42a060af67d08b12d7d1970b7889d685..9a4441bbeef26d7bf39fe8bb9148a7e8a4ef5632 100644 (file)
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1130,7 +1130,7 @@ static void frag_stop(struct seq_file *m, void *arg)
  * If @assert_populated is true, only use callback for zones that are populated.
  */
 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
-               bool assert_populated,
+               bool assert_populated, bool nolock,
                void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
 {
        struct zone *zone;
@@ -1141,9 +1141,11 @@ static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
                if (assert_populated && !populated_zone(zone))
                        continue;
 
-               spin_lock_irqsave(&zone->lock, flags);
+               if (!nolock)
+                       spin_lock_irqsave(&zone->lock, flags);
                print(m, pgdat, zone);
-               spin_unlock_irqrestore(&zone->lock, flags);
+               if (!nolock)
+                       spin_unlock_irqrestore(&zone->lock, flags);
        }
 }
 #endif
@@ -1166,7 +1168,7 @@ static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
 static int frag_show(struct seq_file *m, void *arg)
 {
        pg_data_t *pgdat = (pg_data_t *)arg;
-       walk_zones_in_node(m, pgdat, true, frag_show_print);
+       walk_zones_in_node(m, pgdat, true, false, frag_show_print);
        return 0;
 }
 
@@ -1207,7 +1209,7 @@ static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
                seq_printf(m, "%6d ", order);
        seq_putc(m, '\n');
 
-       walk_zones_in_node(m, pgdat, true, pagetypeinfo_showfree_print);
+       walk_zones_in_node(m, pgdat, true, false, pagetypeinfo_showfree_print);
 
        return 0;
 }
@@ -1258,7 +1260,8 @@ static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
        for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
                seq_printf(m, "%12s ", migratetype_names[mtype]);
        seq_putc(m, '\n');
-       walk_zones_in_node(m, pgdat, true, pagetypeinfo_showblockcount_print);
+       walk_zones_in_node(m, pgdat, true, false,
+               pagetypeinfo_showblockcount_print);
 
        return 0;
 }
@@ -1284,7 +1287,8 @@ static void pagetypeinfo_showmixedcount(struct seq_file *m, pg_data_t *pgdat)
                seq_printf(m, "%12s ", migratetype_names[mtype]);
        seq_putc(m, '\n');
 
-       walk_zones_in_node(m, pgdat, true, pagetypeinfo_showmixedcount_print);
+       walk_zones_in_node(m, pgdat, true, true,
+               pagetypeinfo_showmixedcount_print);
 #endif /* CONFIG_PAGE_OWNER */
 }
 
@@ -1446,7 +1450,7 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
 static int zoneinfo_show(struct seq_file *m, void *arg)
 {
        pg_data_t *pgdat = (pg_data_t *)arg;
-       walk_zones_in_node(m, pgdat, false, zoneinfo_show_print);
+       walk_zones_in_node(m, pgdat, false, false, zoneinfo_show_print);
        return 0;
 }
 
@@ -1852,7 +1856,7 @@ static int unusable_show(struct seq_file *m, void *arg)
        if (!node_state(pgdat->node_id, N_MEMORY))
                return 0;
 
-       walk_zones_in_node(m, pgdat, true, unusable_show_print);
+       walk_zones_in_node(m, pgdat, true, false, unusable_show_print);
 
        return 0;
 }
@@ -1904,7 +1908,7 @@ static int extfrag_show(struct seq_file *m, void *arg)
 {
        pg_data_t *pgdat = (pg_data_t *)arg;
 
-       walk_zones_in_node(m, pgdat, true, extfrag_show_print);
+       walk_zones_in_node(m, pgdat, true, false, extfrag_show_print);
 
        return 0;
 }