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authorKai Krakow2021-02-10 13:07:25 +0800
committerJens Axboe2021-02-10 08:06:00 -0700
commit9f233ffe02e5cef611100cd8c5bcf4de26ca7bef (patch)
treece11b65a8b1bf85fa471d182a2a9a106ecf602dc /drivers/md
parentd7fae7b4fa152795ab70c680d3a63c7843c9368c (diff)
Revert "bcache: Kill btree_io_wq"
This reverts commit 56b30770b27d54d68ad51eccc6d888282b568cee. With the btree using the `system_wq`, I seem to see a lot more desktop latency than I should. After some more investigation, it looks like the original assumption of 56b3077 no longer is true, and bcache has a very high potential of congesting the `system_wq`. In turn, this introduces laggy desktop performance, IO stalls (at least with btrfs), and input events may be delayed. So let's revert this. It's important to note that the semantics of using `system_wq` previously mean that `btree_io_wq` should be created before and destroyed after other bcache wqs to keep the same assumptions. Cc: Coly Li <colyli@suse.de> Cc: stable@vger.kernel.org # 5.4+ Signed-off-by: Kai Krakow <kai@kaishome.de> 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/bcache.h2
-rw-r--r--drivers/md/bcache/btree.c21
-rw-r--r--drivers/md/bcache/super.c4
3 files changed, 25 insertions, 2 deletions
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index d7a84327b7f1..2b8c7dd2cfae 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -1046,5 +1046,7 @@ void bch_debug_exit(void);
void bch_debug_init(void);
void bch_request_exit(void);
int bch_request_init(void);
+void bch_btree_exit(void);
+int bch_btree_init(void);
#endif /* _BCACHE_H */
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 910df242c83d..952f022db5a5 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -99,6 +99,8 @@
#define PTR_HASH(c, k) \
(((k)->ptr[0] >> c->bucket_bits) | PTR_GEN(k, 0))
+static struct workqueue_struct *btree_io_wq;
+
#define insert_lock(s, b) ((b)->level <= (s)->lock)
@@ -308,7 +310,7 @@ static void __btree_node_write_done(struct closure *cl)
btree_complete_write(b, w);
if (btree_node_dirty(b))
- schedule_delayed_work(&b->work, 30 * HZ);
+ queue_delayed_work(btree_io_wq, &b->work, 30 * HZ);
closure_return_with_destructor(cl, btree_node_write_unlock);
}
@@ -481,7 +483,7 @@ static void bch_btree_leaf_dirty(struct btree *b, atomic_t *journal_ref)
BUG_ON(!i->keys);
if (!btree_node_dirty(b))
- schedule_delayed_work(&b->work, 30 * HZ);
+ queue_delayed_work(btree_io_wq, &b->work, 30 * HZ);
set_btree_node_dirty(b);
@@ -2764,3 +2766,18 @@ void bch_keybuf_init(struct keybuf *buf)
spin_lock_init(&buf->lock);
array_allocator_init(&buf->freelist);
}
+
+void bch_btree_exit(void)
+{
+ if (btree_io_wq)
+ destroy_workqueue(btree_io_wq);
+}
+
+int __init bch_btree_init(void)
+{
+ btree_io_wq = create_singlethread_workqueue("bch_btree_io");
+ if (!btree_io_wq)
+ return -ENOMEM;
+
+ return 0;
+}
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index dfbaf6aa3e4f..97405aec4b51 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -2821,6 +2821,7 @@ static void bcache_exit(void)
destroy_workqueue(bcache_wq);
if (bch_journal_wq)
destroy_workqueue(bch_journal_wq);
+ bch_btree_exit();
if (bcache_major)
unregister_blkdev(bcache_major, "bcache");
@@ -2876,6 +2877,9 @@ static int __init bcache_init(void)
return bcache_major;
}
+ if (bch_btree_init())
+ goto err;
+
bcache_wq = alloc_workqueue("bcache", WQ_MEM_RECLAIM, 0);
if (!bcache_wq)
goto err;