diff options
| author | Satoru Moriya <satoru.moriya@hds.com> | 2012-05-29 15:06:47 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-10-02 10:30:38 -0700 |
| commit | 49194d4e7d8c14fb83f213c54a476685f8389c70 (patch) | |
| tree | a773acfde98ebc23d3ecd56067e2e31a5f0bcbb3 | |
| parent | 642550436c8b3a933550468996ef547630344a0e (diff) | |
mm: avoid swapping out with swappiness==0
commit fe35004fbf9eaf67482b074a2e032abb9c89b1dd upstream.
Sometimes we'd like to avoid swapping out anonymous memory. In
particular, avoid swapping out pages of important process or process
groups while there is a reasonable amount of pagecache on RAM so that we
can satisfy our customers' requirements.
OTOH, we can control how aggressive the kernel will swap memory pages with
/proc/sys/vm/swappiness for global and
/sys/fs/cgroup/memory/memory.swappiness for each memcg.
But with current reclaim implementation, the kernel may swap out even if
we set swappiness=0 and there is pagecache in RAM.
This patch changes the behavior with swappiness==0. If we set
swappiness==0, the kernel does not swap out completely (for global reclaim
until the amount of free pages and filebacked pages in a zone has been
reduced to something very very small (nr_free + nr_filebacked < high
watermark)).
Signed-off-by: Satoru Moriya <satoru.moriya@hds.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | mm/vmscan.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index be5bc0af2e7..e989ee22f10 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1983,10 +1983,10 @@ static void get_scan_count(struct mem_cgroup_zone *mz, struct scan_control *sc, * proportional to the fraction of recently scanned pages on * each list that were recently referenced and in active use. */ - ap = (anon_prio + 1) * (reclaim_stat->recent_scanned[0] + 1); + ap = anon_prio * (reclaim_stat->recent_scanned[0] + 1); ap /= reclaim_stat->recent_rotated[0] + 1; - fp = (file_prio + 1) * (reclaim_stat->recent_scanned[1] + 1); + fp = file_prio * (reclaim_stat->recent_scanned[1] + 1); fp /= reclaim_stat->recent_rotated[1] + 1; spin_unlock_irq(&mz->zone->lru_lock); @@ -1999,7 +1999,7 @@ out: unsigned long scan; scan = zone_nr_lru_pages(mz, lru); - if (priority || noswap) { + if (priority || noswap || !vmscan_swappiness(mz, sc)) { scan >>= priority; if (!scan && force_scan) scan = SWAP_CLUSTER_MAX; |