diff options
author | Konstantin Khlebnikov <khlebnikov@openvz.org> | 2011-12-08 17:33:51 -0500 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-12-09 10:50:27 -0500 |
commit | 635697c663f38106063d5659f0cf2e45afcd4bb5 (patch) | |
tree | 3aba50aabc16eeb63d5e21979a3fdf163ccabda2 /mm/vmscan.c | |
parent | 09d9673d53005fdf40de4c759425893904292236 (diff) |
vmscan: fix initial shrinker size handling
A shrinker function can return -1, means that it cannot do anything
without a risk of deadlock. For example prune_super() does this if it
cannot grab a superblock refrence, even if nr_to_scan=0. Currently we
interpret this -1 as a ULONG_MAX size shrinker and evaluate `total_scan'
according to this. So the next time around this shrinker can cause
really big pressure. Let's skip such shrinkers instead.
Also make total_scan signed, otherwise the check (total_scan < 0) below
never works.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmscan.c')
-rw-r--r-- | mm/vmscan.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index a1893c050795..f5255442ae2b 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c | |||
@@ -247,14 +247,18 @@ unsigned long shrink_slab(struct shrink_control *shrink, | |||
247 | 247 | ||
248 | list_for_each_entry(shrinker, &shrinker_list, list) { | 248 | list_for_each_entry(shrinker, &shrinker_list, list) { |
249 | unsigned long long delta; | 249 | unsigned long long delta; |
250 | unsigned long total_scan; | 250 | long total_scan; |
251 | unsigned long max_pass; | 251 | long max_pass; |
252 | int shrink_ret = 0; | 252 | int shrink_ret = 0; |
253 | long nr; | 253 | long nr; |
254 | long new_nr; | 254 | long new_nr; |
255 | long batch_size = shrinker->batch ? shrinker->batch | 255 | long batch_size = shrinker->batch ? shrinker->batch |
256 | : SHRINK_BATCH; | 256 | : SHRINK_BATCH; |
257 | 257 | ||
258 | max_pass = do_shrinker_shrink(shrinker, shrink, 0); | ||
259 | if (max_pass <= 0) | ||
260 | continue; | ||
261 | |||
258 | /* | 262 | /* |
259 | * copy the current shrinker scan count into a local variable | 263 | * copy the current shrinker scan count into a local variable |
260 | * and zero it so that other concurrent shrinker invocations | 264 | * and zero it so that other concurrent shrinker invocations |
@@ -265,7 +269,6 @@ unsigned long shrink_slab(struct shrink_control *shrink, | |||
265 | } while (cmpxchg(&shrinker->nr, nr, 0) != nr); | 269 | } while (cmpxchg(&shrinker->nr, nr, 0) != nr); |
266 | 270 | ||
267 | total_scan = nr; | 271 | total_scan = nr; |
268 | max_pass = do_shrinker_shrink(shrinker, shrink, 0); | ||
269 | delta = (4 * nr_pages_scanned) / shrinker->seeks; | 272 | delta = (4 * nr_pages_scanned) / shrinker->seeks; |
270 | delta *= max_pass; | 273 | delta *= max_pass; |
271 | do_div(delta, lru_pages + 1); | 274 | do_div(delta, lru_pages + 1); |