Commit 35cd7815 authored by Rik van Riel's avatar Rik van Riel Committed by Linus Torvalds

vmscan: throttle direct reclaim when too many pages are isolated already

When way too many processes go into direct reclaim, it is possible for all
of the pages to be taken off the LRU.  One result of this is that the next
process in the page reclaim code thinks there are no reclaimable pages
left and triggers an out of memory kill.

One solution to this problem is to never let so many processes into the
page reclaim path that the entire LRU is emptied.  Limiting the system to
only having half of each inactive list isolated for reclaim should be
safe.
Signed-off-by: default avatarRik van Riel <riel@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a731286d
...@@ -1033,6 +1033,31 @@ int isolate_lru_page(struct page *page) ...@@ -1033,6 +1033,31 @@ int isolate_lru_page(struct page *page)
return ret; return ret;
} }
/*
* Are there way too many processes in the direct reclaim path already?
*/
static int too_many_isolated(struct zone *zone, int file,
struct scan_control *sc)
{
unsigned long inactive, isolated;
if (current_is_kswapd())
return 0;
if (!scanning_global_lru(sc))
return 0;
if (file) {
inactive = zone_page_state(zone, NR_INACTIVE_FILE);
isolated = zone_page_state(zone, NR_ISOLATED_FILE);
} else {
inactive = zone_page_state(zone, NR_INACTIVE_ANON);
isolated = zone_page_state(zone, NR_ISOLATED_ANON);
}
return isolated > inactive;
}
/* /*
* shrink_inactive_list() is a helper for shrink_zone(). It returns the number * shrink_inactive_list() is a helper for shrink_zone(). It returns the number
* of reclaimed pages * of reclaimed pages
...@@ -1048,6 +1073,14 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, ...@@ -1048,6 +1073,14 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
int lumpy_reclaim = 0; int lumpy_reclaim = 0;
while (unlikely(too_many_isolated(zone, file, sc))) {
congestion_wait(WRITE, HZ/10);
/* We are about to die and free our memory. Return now. */
if (fatal_signal_pending(current))
return SWAP_CLUSTER_MAX;
}
/* /*
* If we need a large contiguous chunk of memory, or have * If we need a large contiguous chunk of memory, or have
* trouble getting a small set of contiguous pages, we * trouble getting a small set of contiguous pages, we
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment