Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Subject | [PATCH 1/2] vmscan: fix initial shrinker size handling | From | Konstantin Khlebnikov <> | Date | Mon, 22 Aug 2011 14:17:21 +0300 |
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Shrinker function can returns -1, it means it cannot do anything without a risk of deadlock. For example prune_super() do this if it cannot grab superblock refrence, even if nr_to_scan=0. Currenly we interpret this like ULONG_MAX size shrinker, evaluate total_scan according this, and next time this shrinker can get really big pressure. Let's skip such shrinkers instead.
Also make total_scan signed, otherwise check (total_scan < 0) below never works.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> --- mm/vmscan.c | 9 ++++++--- 1 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c index 29b3612..f174561 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -248,14 +248,18 @@ unsigned long shrink_slab(struct shrink_control *shrink, list_for_each_entry(shrinker, &shrinker_list, list) { unsigned long long delta; - unsigned long total_scan; - unsigned long max_pass; + long total_scan; + long max_pass; int shrink_ret = 0; long nr; long new_nr; long batch_size = shrinker->batch ? shrinker->batch : SHRINK_BATCH; + max_pass = do_shrinker_shrink(shrinker, shrink, 0); + if (max_pass <= 0) + continue; + /* * copy the current shrinker scan count into a local variable * and zero it so that other concurrent shrinker invocations @@ -266,7 +270,6 @@ unsigned long shrink_slab(struct shrink_control *shrink, } while (cmpxchg(&shrinker->nr, nr, 0) != nr); total_scan = nr; - max_pass = do_shrinker_shrink(shrinker, shrink, 0); delta = (4 * nr_pages_scanned) / shrinker->seeks; delta *= max_pass; do_div(delta, lru_pages + 1);
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