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authorMikulas Patocka <mpatocka@redhat.com>2016-11-23 17:04:00 -0500
committerMike Snitzer <snitzer@redhat.com>2016-12-08 14:13:05 -0500
commit41c73a49df31151f4ff868f28fe4f129f113fa2c (patch)
tree673d805c470b5aed20be74336a089e427d92a933 /drivers/md/dm-bufio.c
parentd12067f428c037b4575aaeb2be00847fc214c24a (diff)
dm bufio: drop the lock when doing GFP_NOIO allocation
If the first allocation attempt using GFP_NOWAIT fails, drop the lock and retry using GFP_NOIO allocation (lock is dropped because the allocation can take some time). Note that we won't do GFP_NOIO allocation when we loop for the second time, because the lock shouldn't be dropped between __wait_for_free_buffer and __get_unclaimed_buffer. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-bufio.c')
-rw-r--r--drivers/md/dm-bufio.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index 9ef88f0e2382..1c2e1dd7ca16 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -822,6 +822,7 @@ enum new_flag {
static struct dm_buffer *__alloc_buffer_wait_no_callback(struct dm_bufio_client *c, enum new_flag nf)
{
struct dm_buffer *b;
+ bool tried_noio_alloc = false;
/*
* dm-bufio is resistant to allocation failures (it just keeps
@@ -846,6 +847,15 @@ static struct dm_buffer *__alloc_buffer_wait_no_callback(struct dm_bufio_client
if (nf == NF_PREFETCH)
return NULL;
+ if (dm_bufio_cache_size_latch != 1 && !tried_noio_alloc) {
+ dm_bufio_unlock(c);
+ b = alloc_buffer(c, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
+ dm_bufio_lock(c);
+ if (b)
+ return b;
+ tried_noio_alloc = true;
+ }
+
if (!list_empty(&c->reserved_buffers)) {
b = list_entry(c->reserved_buffers.next,
struct dm_buffer, lru_list);