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| author | Tang Junhui <tang.junhui@zte.com.cn> | 2018-03-18 17:36:22 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-03-18 20:15:20 -0600 |
| commit | ca71df31661a0518ed58a1a59cf1993962153ebb (patch) | |
| tree | b1804803052dbad87886ce0284a93369fa915f7a /drivers/md | |
| parent | f3641c3abd1da978ee969b0203b71b86ec1bfa93 (diff) | |
| download | linux-ca71df31661a0518ed58a1a59cf1993962153ebb.tar.bz2 | |
bcache: fix using of loop variable in memory shrink
In bch_mca_scan(), There are some confusion and logical error in the use of
loop variables. In this patch, we clarify them as:
1) nr: the number of btree nodes needs to scan, which will decrease after
we scan a btree node, and should not be less than 0;
2) i: the number of btree nodes have scanned, includes both
btree_cache_freeable and btree_cache, which should not be bigger than
btree_cache_used;
3) freed: the number of btree nodes have freed.
Signed-off-by: Tang Junhui <tang.junhui@zte.com.cn>
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/bcache/btree.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c index b2d4899f48d5..d64aff0b8abc 100644 --- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -665,6 +665,7 @@ static unsigned long bch_mca_scan(struct shrinker *shrink, struct btree *b, *t; unsigned long i, nr = sc->nr_to_scan; unsigned long freed = 0; + unsigned int btree_cache_used; if (c->shrinker_disabled) return SHRINK_STOP; @@ -689,9 +690,10 @@ static unsigned long bch_mca_scan(struct shrinker *shrink, nr = min_t(unsigned long, nr, mca_can_free(c)); i = 0; + btree_cache_used = c->btree_cache_used; list_for_each_entry_safe(b, t, &c->btree_cache_freeable, list) { - if (freed >= nr) - break; + if (nr <= 0) + goto out; if (++i > 3 && !mca_reap(b, 0, false)) { @@ -699,9 +701,10 @@ static unsigned long bch_mca_scan(struct shrinker *shrink, rw_unlock(true, b); freed++; } + nr--; } - for (i = 0; (nr--) && i < c->btree_cache_used; i++) { + for (; (nr--) && i < btree_cache_used; i++) { if (list_empty(&c->btree_cache)) goto out; |