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authorColy Li <colyli@suse.de>2019-06-28 19:59:54 +0800
committerJens Axboe <axboe@kernel.dk>2019-06-28 07:39:17 -0600
commit249a5f6da57c28a903c75d81505d58ec8c10030d (patch)
tree8d1b48b0a00a6075f24cb5661e1f4cde84135f6c /drivers/md
parentba82c1ac1667d6efb91a268edb13fc9cdaecec9b (diff)
downloadlinux-249a5f6da57c28a903c75d81505d58ec8c10030d.tar.bz2
bcache: Revert "bcache: fix high CPU occupancy during journal"
This reverts commit c4dc2497d50d9c6fb16aa0d07b6a14f3b2adb1e0. This patch enlarges a race between normal btree flush code path and flush_btree_write(), which causes deadlock when journal space is exhausted. Reverts this patch makes the race window from 128 btree nodes to only 1 btree nodes. Fixes: c4dc2497d50d ("bcache: fix high CPU occupancy during journal") Signed-off-by: Coly Li <colyli@suse.de> Cc: stable@vger.kernel.org Cc: Tang Junhui <tang.junhui.linux@gmail.com> 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/journal.c47
-rw-r--r--drivers/md/bcache/util.h2
3 files changed, 15 insertions, 36 deletions
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 73a97586a2ef..cb268d7c6cea 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -726,8 +726,6 @@ struct cache_set {
#define BUCKET_HASH_BITS 12
struct hlist_head bucket_hash[1 << BUCKET_HASH_BITS];
-
- DECLARE_HEAP(struct btree *, flush_btree);
};
struct bbio {
diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c
index 11d8c93b88bb..14a4e2c44de9 100644
--- a/drivers/md/bcache/journal.c
+++ b/drivers/md/bcache/journal.c
@@ -416,12 +416,6 @@ err:
}
/* Journalling */
-#define journal_max_cmp(l, r) \
- (fifo_idx(&c->journal.pin, btree_current_write(l)->journal) < \
- fifo_idx(&(c)->journal.pin, btree_current_write(r)->journal))
-#define journal_min_cmp(l, r) \
- (fifo_idx(&c->journal.pin, btree_current_write(l)->journal) > \
- fifo_idx(&(c)->journal.pin, btree_current_write(r)->journal))
static void btree_flush_write(struct cache_set *c)
{
@@ -429,35 +423,25 @@ static void btree_flush_write(struct cache_set *c)
* Try to find the btree node with that references the oldest journal
* entry, best is our current candidate and is locked if non NULL:
*/
- struct btree *b;
- int i;
+ struct btree *b, *best;
+ unsigned int i;
atomic_long_inc(&c->flush_write);
-
retry:
- spin_lock(&c->journal.lock);
- if (heap_empty(&c->flush_btree)) {
- for_each_cached_btree(b, c, i)
- if (btree_current_write(b)->journal) {
- if (!heap_full(&c->flush_btree))
- heap_add(&c->flush_btree, b,
- journal_max_cmp);
- else if (journal_max_cmp(b,
- heap_peek(&c->flush_btree))) {
- c->flush_btree.data[0] = b;
- heap_sift(&c->flush_btree, 0,
- journal_max_cmp);
- }
+ best = NULL;
+
+ for_each_cached_btree(b, c, i)
+ if (btree_current_write(b)->journal) {
+ if (!best)
+ best = b;
+ else if (journal_pin_cmp(c,
+ btree_current_write(best)->journal,
+ btree_current_write(b)->journal)) {
+ best = b;
}
+ }
- for (i = c->flush_btree.used / 2 - 1; i >= 0; --i)
- heap_sift(&c->flush_btree, i, journal_min_cmp);
- }
-
- b = NULL;
- heap_pop(&c->flush_btree, b, journal_min_cmp);
- spin_unlock(&c->journal.lock);
-
+ b = best;
if (b) {
mutex_lock(&b->write_lock);
if (!btree_current_write(b)->journal) {
@@ -898,8 +882,7 @@ int bch_journal_alloc(struct cache_set *c)
j->w[0].c = c;
j->w[1].c = c;
- if (!(init_heap(&c->flush_btree, 128, GFP_KERNEL)) ||
- !(init_fifo(&j->pin, JOURNAL_PIN, GFP_KERNEL)) ||
+ if (!(init_fifo(&j->pin, JOURNAL_PIN, GFP_KERNEL)) ||
!(j->w[0].data = (void *) __get_free_pages(GFP_KERNEL, JSET_BITS)) ||
!(j->w[1].data = (void *) __get_free_pages(GFP_KERNEL, JSET_BITS)))
return -ENOMEM;
diff --git a/drivers/md/bcache/util.h b/drivers/md/bcache/util.h
index 1fbced94e4cc..c029f7443190 100644
--- a/drivers/md/bcache/util.h
+++ b/drivers/md/bcache/util.h
@@ -113,8 +113,6 @@ do { \
#define heap_full(h) ((h)->used == (h)->size)
-#define heap_empty(h) ((h)->used == 0)
-
#define DECLARE_FIFO(type, name) \
struct { \
size_t front, back, size, mask; \