Messages in this thread | | | Date | Tue, 19 Jul 2022 09:53:55 -0600 | Subject | Re: [PATCH v2] block: don't allow the same type rq_qos add more than once | From | Jens Axboe <> |
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On 7/19/22 1:02 AM, Jinke Han wrote: > From: Jinke Han <hanjinke.666@bytedance.com> > > In our test of iocost, we encounttered some list add/del corrutions of
encountered and corruptions
> inner_walk list in ioc_timer_fn. > > The reason can be descripted as follow:
described
> cpu 0 cpu 1 > ioc_qos_write ioc_qos_write > > ioc = q_to_ioc(bdev_get_queue(bdev)); > if (!ioc) { > ioc = kzalloc(); ioc = q_to_ioc(bdev_get_queue(bdev)); > if (!ioc) { > ioc = kzalloc(); > ... > rq_qos_add(q, rqos); > } > ... > rq_qos_add(q, rqos); > ... > } > > When the io.cost.qos file is written by two cpu concurrently, rq_qos may
two cpus
> be added to one disk twice. In that case, there will be two iocs enabled > and running on one disk. They own different iocgs on their active list. > In the ioc_timer_fn function, because of the iocgs from two ioc have the > same root iocg, the root iocg's walk_list may be overwritten by each > other and this lead to list add/del corrutions in building or destorying
leads to, corruptions, destroying.
Outside of the spelling and grammer which I typically just fix up while applying, this one doesn't apply to for-5.20/block. Please check and resend it.
-- Jens Axboe
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