Re: [PATCH BUGFIX] block, bfq: deschedule empty bfq_queues not referred by any process

From: Oleksandr Natalenko
Date: Thu Nov 14 2019 - 03:53:30 EST


Hi.

On 13.11.2019 18:42, Paolo Valente wrote:
Il giorno 13 nov 2019, alle ore 16:01, Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx> ha scritto:
Ok, you may have given me enough information, thank you very much.

Could you please apply the attached (compressed) patch on top of my
offending patch? For review purposes, here is the simple change:

--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -2728,7 +2728,8 @@ void bfq_release_process_ref(struct bfq_data
*bfqd, struct bfq_queue *bfqq)
* freed when dequeued from service. But this is assumed to
* never happen.
*/
- if (bfq_bfqq_busy(bfqq) && RB_EMPTY_ROOT(&bfqq->sort_list))
+ if (bfq_bfqq_busy(bfqq) && RB_EMPTY_ROOT(&bfqq->sort_list) &&
+ bfqq != bfqd->in_service_queue)
bfq_del_bfqq_busy(bfqd, bfqq, false);

bfq_put_queue(bfqq);

The issue is not reproducible for me after applying this patch.

Thank you.

--
Oleksandr Natalenko (post-factum)