mm: vmscan: distinguish global reclaim from global LRU scanning
The traditional zone reclaim code is scanning the per-zone LRU lists
during direct reclaim and kswapd, and the per-zone per-memory cgroup LRU
lists when reclaiming on behalf of a memory cgroup limit.
Subsequent patches will convert the traditional reclaim code to reclaim
exclusively from the per-memory cgroup LRU lists. As a result, using
the predicate for which LRU list is scanned will no longer be
appropriate to tell global reclaim from limit reclaim.
This patch adds a global_reclaim() predicate to tell direct/kswapd
reclaim from memory cgroup limit reclaim and substitutes it in all
places where currently scanning_global_lru() is used for that.
Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Ying Han <yinghan@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 26f4a8a..ee4a46b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -153,9 +153,25 @@
static DECLARE_RWSEM(shrinker_rwsem);
#ifdef CONFIG_CGROUP_MEM_RES_CTLR
-#define scanning_global_lru(sc) (!(sc)->mem_cgroup)
+static bool global_reclaim(struct scan_control *sc)
+{
+ return !sc->mem_cgroup;
+}
+
+static bool scanning_global_lru(struct scan_control *sc)
+{
+ return !sc->mem_cgroup;
+}
#else
-#define scanning_global_lru(sc) (1)
+static bool global_reclaim(struct scan_control *sc)
+{
+ return true;
+}
+
+static bool scanning_global_lru(struct scan_control *sc)
+{
+ return true;
+}
#endif
static struct zone_reclaim_stat *get_reclaim_stat(struct zone *zone,
@@ -994,7 +1010,7 @@
* back off and wait for congestion to clear because further reclaim
* will encounter the same problem
*/
- if (nr_dirty && nr_dirty == nr_congested && scanning_global_lru(sc))
+ if (nr_dirty && nr_dirty == nr_congested && global_reclaim(sc))
zone_set_flag(zone, ZONE_CONGESTED);
free_hot_cold_page_list(&free_pages, 1);
@@ -1313,7 +1329,7 @@
if (current_is_kswapd())
return 0;
- if (!scanning_global_lru(sc))
+ if (!global_reclaim(sc))
return 0;
if (file) {
@@ -1491,6 +1507,12 @@
if (scanning_global_lru(sc)) {
nr_taken = isolate_pages_global(nr_to_scan, &page_list,
&nr_scanned, sc->order, reclaim_mode, zone, 0, file);
+ } else {
+ nr_taken = mem_cgroup_isolate_pages(nr_to_scan, &page_list,
+ &nr_scanned, sc->order, reclaim_mode, zone,
+ sc->mem_cgroup, 0, file);
+ }
+ if (global_reclaim(sc)) {
zone->pages_scanned += nr_scanned;
if (current_is_kswapd())
__count_zone_vm_events(PGSCAN_KSWAPD, zone,
@@ -1498,14 +1520,6 @@
else
__count_zone_vm_events(PGSCAN_DIRECT, zone,
nr_scanned);
- } else {
- nr_taken = mem_cgroup_isolate_pages(nr_to_scan, &page_list,
- &nr_scanned, sc->order, reclaim_mode, zone,
- sc->mem_cgroup, 0, file);
- /*
- * mem_cgroup_isolate_pages() keeps track of
- * scanned pages on its own.
- */
}
if (nr_taken == 0) {
@@ -1646,18 +1660,16 @@
&pgscanned, sc->order,
reclaim_mode, zone,
1, file);
- zone->pages_scanned += pgscanned;
} else {
nr_taken = mem_cgroup_isolate_pages(nr_pages, &l_hold,
&pgscanned, sc->order,
reclaim_mode, zone,
sc->mem_cgroup, 1, file);
- /*
- * mem_cgroup_isolate_pages() keeps track of
- * scanned pages on its own.
- */
}
+ if (global_reclaim(sc))
+ zone->pages_scanned += pgscanned;
+
reclaim_stat->recent_scanned[file] += nr_taken;
__count_zone_vm_events(PGREFILL, zone, pgscanned);
@@ -1827,7 +1839,7 @@
static int vmscan_swappiness(struct scan_control *sc)
{
- if (scanning_global_lru(sc))
+ if (global_reclaim(sc))
return vm_swappiness;
return mem_cgroup_swappiness(sc->mem_cgroup);
}
@@ -1862,9 +1874,9 @@
* latencies, so it's better to scan a minimum amount there as
* well.
*/
- if (scanning_global_lru(sc) && current_is_kswapd())
+ if (current_is_kswapd())
force_scan = true;
- if (!scanning_global_lru(sc))
+ if (!global_reclaim(sc))
force_scan = true;
/* If we have no swap space, do not bother scanning anon pages. */
@@ -1881,7 +1893,7 @@
file = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_FILE) +
zone_nr_lru_pages(zone, sc, LRU_INACTIVE_FILE);
- if (scanning_global_lru(sc)) {
+ if (global_reclaim(sc)) {
free = zone_page_state(zone, NR_FREE_PAGES);
/* If we have very few page cache pages,
force-scan anon pages. */
@@ -2114,7 +2126,7 @@
* Take care memory controller reclaiming has small influence
* to global LRU.
*/
- if (scanning_global_lru(sc)) {
+ if (global_reclaim(sc)) {
if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
continue;
if (zone->all_unreclaimable && priority != DEF_PRIORITY)
@@ -2212,7 +2224,7 @@
get_mems_allowed();
delayacct_freepages_start();
- if (scanning_global_lru(sc))
+ if (global_reclaim(sc))
count_vm_event(ALLOCSTALL);
for (priority = DEF_PRIORITY; priority >= 0; priority--) {
@@ -2226,7 +2238,7 @@
* Don't shrink slabs when reclaiming memory from
* over limit cgroups
*/
- if (scanning_global_lru(sc)) {
+ if (global_reclaim(sc)) {
unsigned long lru_pages = 0;
for_each_zone_zonelist(zone, z, zonelist,
gfp_zone(sc->gfp_mask)) {
@@ -2288,7 +2300,7 @@
return 0;
/* top priority shrink_zones still had more to do? don't OOM, then */
- if (scanning_global_lru(sc) && !all_unreclaimable(zonelist, sc))
+ if (global_reclaim(sc) && !all_unreclaimable(zonelist, sc))
return 1;
return 0;