diff options
| author | Coly Li | 2020-01-24 01:01:40 +0800 |
|---|---|---|
| committer | Jens Axboe | 2020-01-23 11:40:02 -0700 |
| commit | 125d98edd11464c8e0ec9eaaba7d682d0f832686 (patch) | |
| tree | 798b83e0607ec12480b4c68a641b73050c1b2b8e /drivers/md | |
| parent | d44330b7f13e7f243f7d0e0426741219708ff7de (diff) | |
bcache: remove member accessed from struct btree
The member 'accessed' of struct btree is used in bch_mca_scan() when
shrinking btree node caches. The original idea is, if b->accessed is
set, clean it and look at next btree node cache from c->btree_cache
list, and only shrink the caches whose b->accessed is cleaned. Then
only cold btree node cache will be shrunk.
But when I/O pressure is high, it is very probably that b->accessed
of a btree node cache will be set again in bch_btree_node_get()
before bch_mca_scan() selects it again. Then there is no chance for
bch_mca_scan() to shrink enough memory back to slub or slab system.
This patch removes member accessed from struct btree, then once a
btree node ache is selected, it will be immediately shunk. By this
change, bch_mca_scan() may release btree node cahce more efficiently.
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/bcache/btree.c | 8 | ||||
| -rw-r--r-- | drivers/md/bcache/btree.h | 2 |
2 files changed, 2 insertions, 8 deletions
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c index 14d6c33b0957..357535a5c89c 100644 --- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -754,14 +754,12 @@ static unsigned long bch_mca_scan(struct shrinker *shrink, b = list_first_entry(&c->btree_cache, struct btree, list); list_rotate_left(&c->btree_cache); - if (!b->accessed && - !mca_reap(b, 0, false)) { + if (!mca_reap(b, 0, false)) { mca_bucket_free(b); mca_data_free(b); rw_unlock(true, b); freed++; - } else - b->accessed = 0; + } } out: mutex_unlock(&c->bucket_lock); @@ -1069,7 +1067,6 @@ retry: BUG_ON(!b->written); b->parent = parent; - b->accessed = 1; for (; i <= b->keys.nsets && b->keys.set[i].size; i++) { prefetch(b->keys.set[i].tree); @@ -1160,7 +1157,6 @@ retry: goto retry; } - b->accessed = 1; b->parent = parent; bch_bset_init_next(&b->keys, b->keys.set->data, bset_magic(&b->c->sb)); diff --git a/drivers/md/bcache/btree.h b/drivers/md/bcache/btree.h index 76cfd121a486..f4dcca449391 100644 --- a/drivers/md/bcache/btree.h +++ b/drivers/md/bcache/btree.h @@ -121,8 +121,6 @@ struct btree { /* Key/pointer for this btree node */ BKEY_PADDED(key); - /* Single bit - set when accessed, cleared by shrinker */ - unsigned long accessed; unsigned long seq; struct rw_semaphore lock; struct cache_set *c; |