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| author | Mikulas Patocka <mpatocka@redhat.com> | 2017-04-30 17:34:53 -0400 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2017-05-01 15:21:42 -0400 |
| commit | 390020ad2af9ca04844c4f3b1f299ad8746d84c8 (patch) | |
| tree | a89be3c8cd0ad3b0959c12eb534c288be9669597 /drivers/md | |
| parent | 1b0fb5a5b2dc0dddcfa575060441a7176ba7ac37 (diff) | |
| download | linux-390020ad2af9ca04844c4f3b1f299ad8746d84c8.tar.gz linux-390020ad2af9ca04844c4f3b1f299ad8746d84c8.tar.bz2 linux-390020ad2af9ca04844c4f3b1f299ad8746d84c8.zip | |
dm bufio: check new buffer allocation watermark every 30 seconds
dm-bufio checks a watermark when it allocates a new buffer in
__bufio_new(). However, it doesn't check the watermark when the user
changes /sys/module/dm_bufio/parameters/max_cache_size_bytes.
This may result in a problem - if the watermark is high enough so that
all possible buffers are allocated and if the user lowers the value of
"max_cache_size_bytes", the watermark will never be checked against the
new value because no new buffer would be allocated.
To fix this, change __evict_old_buffers() so that it checks the
watermark. __evict_old_buffers() is called every 30 seconds, so if the
user reduces "max_cache_size_bytes", dm-bufio will react to this change
within 30 seconds and decrease memory consumption.
Depends-on: 1b0fb5a5b2 ("dm bufio: avoid a possible ABBA deadlock")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/dm-bufio.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index fd28146dd952..c92c31b23e54 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -1796,9 +1796,17 @@ static void __evict_old_buffers(struct dm_bufio_client *c, unsigned long age_hz) struct dm_buffer *b, *tmp; unsigned retain_target = get_retain_buffers(c); unsigned count; + LIST_HEAD(write_list); dm_bufio_lock(c); + __check_watermark(c, &write_list); + if (unlikely(!list_empty(&write_list))) { + dm_bufio_unlock(c); + __flush_write_list(&write_list); + dm_bufio_lock(c); + } + count = c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY]; list_for_each_entry_safe_reverse(b, tmp, &c->lru[LIST_CLEAN], lru_list) { if (count <= retain_target) @@ -1823,6 +1831,8 @@ static void cleanup_old_buffers(void) mutex_lock(&dm_bufio_clients_lock); + __cache_size_refresh(); + list_for_each_entry(c, &dm_bufio_all_clients, client_list) __evict_old_buffers(c, max_age_hz); |