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authorMel Gorman <mel@csn.ul.ie>2011-01-14 02:46:26 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-14 04:32:37 +0300
commitdc83edd941f412e938841b4989be24aa288a1aa6 (patch)
tree07dbc04d544f3200b3b13be1af6c57f44ffa63c8
parent355b09c47a0cbb73b3e65a57c03f157f2e7ddb0b (diff)
downloadlinux-dc83edd941f412e938841b4989be24aa288a1aa6.tar.xz
mm: kswapd: use the classzone idx that kswapd was using for sleeping_prematurely()
When kswapd is woken up for a high-order allocation, it takes account of the highest usable zone by the caller (the classzone idx). During allocation, this index is used to select the lowmem_reserve[] that should be applied to the watermark calculation in zone_watermark_ok(). When balancing a node, kswapd considers the highest unbalanced zone to be the classzone index. This will always be at least be the callers classzone_idx and can be higher. However, sleeping_prematurely() always considers the lowest zone (e.g. ZONE_DMA) to be the classzone index. This means that sleeping_prematurely() can consider a zone to be balanced that is unusable by the allocation request that originally woke kswapd. This patch changes sleeping_prematurely() to use a classzone_idx matching the value it used in balance_pgdat(). Signed-off-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: Eric B Munson <emunson@mgebm.net> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Simon Kirby <sim@hostway.ca> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/vmscan.c29
1 files changed, 16 insertions, 13 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 388a0447b8e8..cfdef0bcc7ab 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2227,7 +2227,8 @@ static bool pgdat_balanced(pg_data_t *pgdat, unsigned long balanced_pages,
}
/* is kswapd sleeping prematurely? */
-static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining)
+static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining,
+ int classzone_idx)
{
int i;
unsigned long balanced = 0;
@@ -2235,7 +2236,7 @@ static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining)
/* If a direct reclaimer woke kswapd within HZ/10, it's premature */
if (remaining)
- return 1;
+ return true;
/* Check the watermark levels */
for (i = 0; i < pgdat->nr_zones; i++) {
@@ -2256,7 +2257,7 @@ static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining)
}
if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone),
- 0, 0))
+ classzone_idx, 0))
all_zones_ok = false;
else
balanced += zone->present_pages;
@@ -2268,7 +2269,7 @@ static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining)
* must be balanced
*/
if (order)
- return pgdat_balanced(pgdat, balanced, 0);
+ return pgdat_balanced(pgdat, balanced, classzone_idx);
else
return !all_zones_ok;
}
@@ -2295,7 +2296,7 @@ static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining)
* of pages is balanced across the zones.
*/
static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
- int classzone_idx)
+ int *classzone_idx)
{
int all_zones_ok;
unsigned long balanced;
@@ -2358,6 +2359,7 @@ loop_again:
if (!zone_watermark_ok_safe(zone, order,
high_wmark_pages(zone), 0, 0)) {
end_zone = i;
+ *classzone_idx = i;
break;
}
}
@@ -2451,12 +2453,12 @@ loop_again:
* spectulatively avoid congestion waits
*/
zone_clear_flag(zone, ZONE_CONGESTED);
- if (i <= classzone_idx)
+ if (i <= *classzone_idx)
balanced += zone->present_pages;
}
}
- if (all_zones_ok || (order && pgdat_balanced(pgdat, balanced, classzone_idx)))
+ if (all_zones_ok || (order && pgdat_balanced(pgdat, balanced, *classzone_idx)))
break; /* kswapd: all done */
/*
* OK, kswapd is getting into trouble. Take a nap, then take
@@ -2485,7 +2487,7 @@ out:
* high-order: Balanced zones must make up at least 25% of the node
* for the node to be balanced
*/
- if (!(all_zones_ok || (order && pgdat_balanced(pgdat, balanced, classzone_idx)))) {
+ if (!(all_zones_ok || (order && pgdat_balanced(pgdat, balanced, *classzone_idx)))) {
cond_resched();
try_to_freeze();
@@ -2546,10 +2548,11 @@ out:
* if another caller entered the allocator slow path while kswapd
* was awake, order will remain at the higher level
*/
+ *classzone_idx = end_zone;
return order;
}
-static void kswapd_try_to_sleep(pg_data_t *pgdat, int order)
+static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, int classzone_idx)
{
long remaining = 0;
DEFINE_WAIT(wait);
@@ -2560,7 +2563,7 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order)
prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
/* Try to sleep for a short interval */
- if (!sleeping_prematurely(pgdat, order, remaining)) {
+ if (!sleeping_prematurely(pgdat, order, remaining, classzone_idx)) {
remaining = schedule_timeout(HZ/10);
finish_wait(&pgdat->kswapd_wait, &wait);
prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
@@ -2570,7 +2573,7 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order)
* After a short sleep, check if it was a premature sleep. If not, then
* go fully to sleep until explicitly woken up.
*/
- if (!sleeping_prematurely(pgdat, order, remaining)) {
+ if (!sleeping_prematurely(pgdat, order, remaining, classzone_idx)) {
trace_mm_vmscan_kswapd_sleep(pgdat->node_id);
/*
@@ -2658,7 +2661,7 @@ static int kswapd(void *p)
order = new_order;
classzone_idx = new_classzone_idx;
} else {
- kswapd_try_to_sleep(pgdat, order);
+ kswapd_try_to_sleep(pgdat, order, classzone_idx);
order = pgdat->kswapd_max_order;
classzone_idx = pgdat->classzone_idx;
pgdat->kswapd_max_order = 0;
@@ -2675,7 +2678,7 @@ static int kswapd(void *p)
*/
if (!ret) {
trace_mm_vmscan_kswapd_wake(pgdat->node_id, order);
- order = balance_pgdat(pgdat, order, classzone_idx);
+ order = balance_pgdat(pgdat, order, &classzone_idx);
}
}
return 0;