From: Christoph Hellwig <hch@infradead.org> To: Ming Lei <ming.lei@redhat.com> Cc: Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org, Jeffle Xu <jefflexu@linux.alibaba.com>, Mike Snitzer <snitzer@redhat.com>, dm-devel@redhat.com, Hannes Reinecke <hare@suse.de> Subject: Re: [PATCH V5 05/12] block: add new field into 'struct bvec_iter' Date: Mon, 12 Apr 2021 10:26:53 +0100 [thread overview] Message-ID: <20210412092653.GA972763@infradead.org> (raw) In-Reply-To: <20210401021927.343727-6-ming.lei@redhat.com> I don't like where this is going. I think the model of storing the polling cookie in the bio is useful, but: (1) I think having this in the iter is a mess. Can you measure if just marking bvec_iter __packed will generate much worse code at all anymore? If not we can just move this into the bio If it really generates much worse code I think you need to pick a different name as as that i really confusing vs the bio field of the same name that is used entirely differenly. Similarly the bio_get_private_data and bio_set_private_data helpers are entirely misnamed, as the names suggest they deal with the bi_private field in struct bio. I actually suspect not having these helpers would be much preferable (2) once we do have the cookie in the bio we need to take advantage of that properly. That is stop returning the cookie up the stack as we do right now but just rely on the bio, which will clean up tons of crap.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org> To: Ming Lei <ming.lei@redhat.com> Cc: Jens Axboe <axboe@kernel.dk>, Mike Snitzer <snitzer@redhat.com>, linux-block@vger.kernel.org, dm-devel@redhat.com, Jeffle Xu <jefflexu@linux.alibaba.com> Subject: Re: [dm-devel] [PATCH V5 05/12] block: add new field into 'struct bvec_iter' Date: Mon, 12 Apr 2021 10:26:53 +0100 [thread overview] Message-ID: <20210412092653.GA972763@infradead.org> (raw) In-Reply-To: <20210401021927.343727-6-ming.lei@redhat.com> I don't like where this is going. I think the model of storing the polling cookie in the bio is useful, but: (1) I think having this in the iter is a mess. Can you measure if just marking bvec_iter __packed will generate much worse code at all anymore? If not we can just move this into the bio If it really generates much worse code I think you need to pick a different name as as that i really confusing vs the bio field of the same name that is used entirely differenly. Similarly the bio_get_private_data and bio_set_private_data helpers are entirely misnamed, as the names suggest they deal with the bi_private field in struct bio. I actually suspect not having these helpers would be much preferable (2) once we do have the cookie in the bio we need to take advantage of that properly. That is stop returning the cookie up the stack as we do right now but just rely on the bio, which will clean up tons of crap. -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel
next prev parent reply other threads:[~2021-04-12 9:31 UTC|newest] Thread overview: 92+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-04-01 2:19 [PATCH V5 00/12] block: support bio based io polling Ming Lei 2021-04-01 2:19 ` [dm-devel] " Ming Lei 2021-04-01 2:19 ` [PATCH V5 01/12] block: add helper of blk_queue_poll Ming Lei 2021-04-01 2:19 ` [dm-devel] " Ming Lei 2021-04-01 2:19 ` [PATCH V5 02/12] block: add one helper to free io_context Ming Lei 2021-04-01 2:19 ` [dm-devel] " Ming Lei 2021-04-01 2:19 ` [PATCH V5 03/12] block: create io poll context for submission and poll task Ming Lei 2021-04-01 2:19 ` [dm-devel] " Ming Lei 2021-04-12 10:19 ` Christoph Hellwig 2021-04-12 10:19 ` [dm-devel] " Christoph Hellwig 2021-04-01 2:19 ` [dm-devel] [PATCH V5 04/12] block: add req flag of REQ_POLL_CTX Ming Lei 2021-04-01 2:19 ` Ming Lei 2021-04-01 2:19 ` [dm-devel] [PATCH V5 05/12] block: add new field into 'struct bvec_iter' Ming Lei 2021-04-01 2:19 ` Ming Lei 2021-04-12 9:26 ` Christoph Hellwig [this message] 2021-04-12 9:26 ` [dm-devel] " Christoph Hellwig 2021-04-13 9:36 ` Ming Lei 2021-04-13 9:36 ` [dm-devel] " Ming Lei 2021-04-01 2:19 ` [dm-devel] [PATCH V5 06/12] block/mq: extract one helper function polling hw queue Ming Lei 2021-04-01 2:19 ` Ming Lei 2021-04-12 9:29 ` Christoph Hellwig 2021-04-12 9:29 ` [dm-devel] " Christoph Hellwig 2021-04-01 2:19 ` [dm-devel] [PATCH V5 07/12] block: prepare for supporting bio_list via other link Ming Lei 2021-04-01 2:19 ` Ming Lei 2021-04-12 10:18 ` Christoph Hellwig 2021-04-12 10:18 ` [dm-devel] " Christoph Hellwig 2021-04-12 11:37 ` Ming Lei 2021-04-12 11:37 ` [dm-devel] " Ming Lei 2021-04-01 2:19 ` [dm-devel] [PATCH V5 08/12] block: use per-task poll context to implement bio based io polling Ming Lei 2021-04-01 2:19 ` Ming Lei 2021-04-12 9:54 ` [dm-devel] " Christoph Hellwig 2021-04-12 9:54 ` Christoph Hellwig 2021-04-12 10:20 ` Ming Lei 2021-04-12 10:20 ` [dm-devel] " Ming Lei 2021-04-12 10:29 ` Christoph Hellwig 2021-04-12 10:29 ` [dm-devel] " Christoph Hellwig 2021-04-12 11:42 ` Ming Lei 2021-04-12 11:42 ` [dm-devel] " Ming Lei 2021-04-12 10:16 ` Christoph Hellwig 2021-04-12 10:16 ` [dm-devel] " Christoph Hellwig 2021-04-12 10:37 ` Ming Lei 2021-04-12 10:37 ` [dm-devel] " Ming Lei 2021-04-01 2:19 ` [PATCH V5 09/12] blk-mq: limit hw queues to be polled in each blk_poll() Ming Lei 2021-04-01 2:19 ` [dm-devel] " Ming Lei 2021-04-01 2:19 ` [PATCH V5 10/12] block: add queue_to_disk() to get gendisk from request_queue Ming Lei 2021-04-01 2:19 ` [dm-devel] " Ming Lei 2021-04-12 12:52 ` Jens Axboe 2021-04-12 12:52 ` [dm-devel] " Jens Axboe 2021-04-01 2:19 ` [PATCH V5 11/12] block: add poll_capable method to support bio-based IO polling Ming Lei 2021-04-01 2:19 ` [dm-devel] " Ming Lei 2021-04-12 9:38 ` Christoph Hellwig 2021-04-12 9:38 ` Christoph Hellwig 2021-04-14 8:38 ` JeffleXu 2021-04-14 8:38 ` [dm-devel] " JeffleXu 2021-04-14 11:24 ` Ming Lei 2021-04-14 11:24 ` Ming Lei 2021-04-15 1:34 ` JeffleXu 2021-04-15 1:34 ` [dm-devel] " JeffleXu 2021-04-15 7:43 ` Ming Lei 2021-04-15 7:43 ` [dm-devel] " Ming Lei 2021-04-15 9:21 ` JeffleXu 2021-04-15 9:21 ` [dm-devel] " JeffleXu 2021-04-15 10:06 ` Ming Lei 2021-04-15 10:06 ` [dm-devel] " Ming Lei 2021-04-15 11:21 ` JeffleXu 2021-04-15 11:21 ` [dm-devel] " JeffleXu 2021-04-15 13:08 ` Ming Lei 2021-04-15 13:08 ` [dm-devel] " Ming Lei 2021-04-16 8:00 ` [PATCH] block: introduce QUEUE_FLAG_POLL_CAP flag Jeffle Xu 2021-04-16 8:00 ` [dm-devel] " Jeffle Xu 2021-04-16 8:42 ` JeffleXu 2021-04-16 8:42 ` [dm-devel] " JeffleXu 2021-04-16 9:07 ` Ming Lei 2021-04-16 9:07 ` [dm-devel] " Ming Lei 2021-04-16 10:20 ` JeffleXu 2021-04-16 10:20 ` [dm-devel] " JeffleXu 2021-04-17 14:06 ` JeffleXu 2021-04-17 14:06 ` [dm-devel] " JeffleXu 2021-04-19 2:21 ` Ming Lei 2021-04-19 2:21 ` [dm-devel] " Ming Lei 2021-04-19 5:40 ` JeffleXu 2021-04-19 5:40 ` [dm-devel] " JeffleXu 2021-04-19 13:36 ` Ming Lei 2021-04-19 13:36 ` [dm-devel] " Ming Lei 2021-04-20 7:25 ` JeffleXu 2021-04-20 7:25 ` [dm-devel] " JeffleXu 2021-04-01 2:19 ` [dm-devel] [PATCH V5 12/12] dm: support IO polling for bio-based dm device Ming Lei 2021-04-01 2:19 ` Ming Lei 2021-04-09 15:39 ` [PATCH V5 00/12] block: support bio based io polling Ming Lei 2021-04-09 15:39 ` [dm-devel] " Ming Lei 2021-04-12 9:46 ` Christoph Hellwig 2021-04-12 9:46 ` Christoph Hellwig
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