From: Hannes Reinecke <hare@suse.de>
To: Christoph Hellwig <hch@lst.de>, Ming Lei <ming.lei@redhat.com>
Cc: axboe@fb.com, Matias Bjorling <mb@lightnvm.io>,
linux-block@vger.kernel.org
Subject: Re: [PATCH 01/10] block: don't decrement nr_phys_segments for physically contigous segments
Date: Tue, 14 May 2019 15:57:47 +0200 [thread overview]
Message-ID: <dd92aaec-f217-ec4f-a51c-8bccaea4c8fb@suse.de> (raw)
In-Reply-To: <20190514135141.GA13683@lst.de>
On 5/14/19 3:51 PM, Christoph Hellwig wrote:
> On Tue, May 14, 2019 at 05:05:45PM +0800, Ming Lei wrote:
>> However we still may make it better, for example, the attached patch can
>> save 10~20% time when running 'mkfs.ntfs -s 512 /dev/vda', lots of small
>> request(63KB) can be merged to big IO(1MB).
>
> And we could save even more time by making the block dev buffered I/O
> path not do stupid things to start with.
>
>>> With the gap devices we have unlimited segment size, see my next patch
>>> to actually enforce that. Which is much more efficient than using
>>
>> But this patch does effect on non-gap device, and actually most of
>> device are non-gap type.
>
> Yes, but only for request merges, and only if merging the requests
> goes over max_requests. The upside is that we actually get a
> nr_phys_segments that mirrors what is in the request, fixing bugs
> in a few drivers, and allowing for follow on patches that significantly
> simplify our I/O path.
>
And we've seen several of these crashes in real life; signature is
'Kernel oops at drivers/scsi/scsi_lib.c:1003'.
So I'm really glad that this one is finally being addressed.
Thanks Christoph!
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah
HRB 21284 (AG Nürnberg)
next prev parent reply other threads:[~2019-05-14 13:57 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-13 6:37 fix nr_phys_segments vs iterators accounting Christoph Hellwig
2019-05-13 6:37 ` [PATCH 01/10] block: don't decrement nr_phys_segments for physically contigous segments Christoph Hellwig
2019-05-13 9:45 ` Ming Lei
2019-05-13 12:03 ` Christoph Hellwig
2019-05-13 12:37 ` Christoph Hellwig
2019-05-14 4:36 ` Ming Lei
2019-05-14 5:14 ` Christoph Hellwig
2019-05-14 9:05 ` Ming Lei
2019-05-14 13:51 ` Christoph Hellwig
2019-05-14 13:57 ` Hannes Reinecke [this message]
2019-05-14 14:27 ` Ming Lei
2019-05-14 14:31 ` Christoph Hellwig
2019-05-14 14:32 ` Christoph Hellwig
2019-05-13 6:37 ` [PATCH 02/10] block: force an unlimited segment size on queues with a virt boundary Christoph Hellwig
2019-05-15 8:19 ` Ming Lei
2019-05-13 6:37 ` [PATCH 03/10] block: remove the segment size check in bio_will_gap Christoph Hellwig
2019-05-15 8:34 ` Ming Lei
2019-05-13 6:37 ` [PATCH 04/10] block: remove the bi_seg_{front,back}_size fields in struct bio Christoph Hellwig
2019-05-13 6:37 ` [PATCH 05/10] block: initialize the write priority in blk_rq_bio_prep Christoph Hellwig
2019-05-13 15:04 ` Chaitanya Kulkarni
2019-05-13 6:37 ` [PATCH 06/10] block: remove blk_init_request_from_bio Christoph Hellwig
2019-05-13 6:37 ` [PATCH 07/10] block: remove the bi_phys_segments field in struct bio Christoph Hellwig
2019-05-13 6:37 ` [PATCH 08/10] block: simplify blk_recalc_rq_segments Christoph Hellwig
2019-05-13 6:37 ` [PATCH 09/10] block: untangle the end of blk_bio_segment_split Christoph Hellwig
2019-05-13 6:37 ` [PATCH 10/10] block: mark blk_rq_bio_prep as inline Christoph Hellwig
2019-05-13 14:57 ` Chaitanya Kulkarni
[not found] ` <CGME20190513063855epcas5p33ef8c4c0a0055bd0b66eadc859796f0f@epcms2p6>
2019-05-13 7:34 ` [PATCH 05/10] block: initialize the write priority in blk_rq_bio_prep Minwoo Im
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