Messages in this thread | | | Subject | Re: [PATCH V2 7/8] nvme: use blk_mq_queue_tag_inflight_iter | From | "jianchao.wang" <> | Date | Wed, 27 Mar 2019 10:45:33 +0800 |
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Hi Keith
On 3/27/19 10:33 AM, Keith Busch wrote: > On Wed, Mar 27, 2019 at 10:27:57AM +0800, jianchao.wang wrote: >> As the comment above, the stable request maybe something that has been freed due to following case, >> 1. a hctx->fq.flush_rq of dead request_queue that shares the same tagset >> 2. a removed io scheduler's sched request >> and this freed request could be allocated by others which may change the field of request->state. > > You're not explaing how that request->state is changed. I understand the > request can be reallocated, but what is changing its state? >
Sorry for my bad description, and lead to the misunderstand. The _free_ below means,
1. a hctx->fq.flush_rq of dead request_queue that shares the same tagset The whole request_queue is cleaned up and freed, so the hctx->fq.flush is freed back to a slab
2. a removed io scheduler's sched request The io scheduled is detached and all of the structures are freed, including the pages where sched requests locates.
So the pointers in tags->rqs[] may point to memory that is not used as a blk layer request.
Thanks Jianchao
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