On 1/30/23 17:52, Ming Lei wrote:
Hi Bart,
On Mon, Jan 30, 2023 at 03:22:57PM -0800, Bart Van Assche wrote:
Since commit 0a9a25ca7843 ("block: let blkcg_gq grab request queue's
refcnt") for many request queues the reference count drops to 1 when
the request queue is destroyed instead of to 0. In other words, the
request queue is leaked. Fix this by reverting that commit.
When/where you observe that the reference count drops to 1 instead of 0?
Do you have kmem leak log?
Probably, the last drop is in blkg_free_workfn().
Hi Ming,
The reference count leak was discovered while I was testing my patch
series that adds support for sub-page limits
(https://lore.kernel.org/linux-block/20230130212656.876311-1-bvanassche@xxxxxxx/T/#t).
The second patch in that series adds a counter that tracks the number of
queues that need support for limits below the page size
(sub_page_limit_queues). I noticed that without this patch that counter
increases but never decreases. With this patch applied, that counter
drops back to zero after having run a test that needs support for
sub-page limits.
Thanks,
Bart.
