From: Pavel Begunkov <asml.silence@gmail.com>
To: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Matthew Wilcox <willy@infradead.org>,
Christoph Hellwig <hch@infradead.org>,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] block: add bio_iov_iter_nvecs for figuring out nr_vecs
Date: Tue, 8 Dec 2020 02:54:03 +0000 [thread overview]
Message-ID: <e51dfc77-9bff-936c-2de3-c03daf908397@gmail.com> (raw)
In-Reply-To: <20201208015030.GC1059392@T590>
On 08/12/2020 01:50, Ming Lei wrote:
> On Mon, Dec 07, 2020 at 06:07:39PM +0000, Pavel Begunkov wrote:
>> On 01/12/2020 12:06, Ming Lei wrote:
>>> Pavel reported that iov_iter_npages is a bit heavy in case of bvec
>>> iter.
>>>
>>> Turns out it isn't necessary to iterate every page in the bvec iter,
>>> and we call iov_iter_npages() just for figuring out how many bio
>>> vecs need to be allocated. And we can simply map each vector in bvec iter
>>> to bio's vec, so just return iter->nr_segs from bio_iov_iter_nvecs() for
>>> bvec iter.
>>>
>>> Also rename local variable 'nr_pages' as 'nr_vecs' which exactly matches its
>>> real usage.
>>>
>>> This patch is based on Mathew's post:
>>
>> Tried this, the system didn't boot + discovered a filesystem blowned after
>> booting with a stable kernel. That's on top of 4498a8536c816 ("block: use
>> an xarray for disk->part_tbl"), which works fine. Ideas?
>
> I guess it is caused by Christoph's "store a pointer to the block_device in struct bio (again)"
> which has been reverted in for-5.11/block.
>
> I'd suggest to run your test against the latest for-5.11/block one more time.
Ah, now it works, thanks for the idea
Unfortunately, I haven't got any logs, it died pretty early
--
Pavel Begunkov
prev parent reply other threads:[~2020-12-08 2:58 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 12:06 [PATCH] block: add bio_iov_iter_nvecs for figuring out nr_vecs Ming Lei
2020-12-01 12:52 ` Matthew Wilcox
2020-12-01 12:59 ` Christoph Hellwig
2020-12-01 13:17 ` Pavel Begunkov
2020-12-01 13:32 ` Christoph Hellwig
2020-12-01 13:36 ` Pavel Begunkov
2020-12-01 13:45 ` Christoph Hellwig
2020-12-01 13:48 ` Pavel Begunkov
2020-12-02 2:10 ` Ming Lei
2020-12-02 8:02 ` Christoph Hellwig
2020-12-03 22:36 ` Johannes Weiner
2020-12-03 23:43 ` Pavel Begunkov
2020-12-04 12:48 ` Christoph Hellwig
2020-12-10 13:18 ` Johannes Weiner
2020-12-11 13:22 ` Pavel Begunkov
2020-12-02 1:46 ` Ming Lei
2020-12-02 14:06 ` Pavel Begunkov
2020-12-02 15:02 ` Christoph Hellwig
2020-12-02 16:56 ` Jens Axboe
2020-12-07 18:07 ` Pavel Begunkov
2020-12-08 1:21 ` Ming Lei
2020-12-08 1:50 ` Ming Lei
2020-12-08 2:54 ` Pavel Begunkov [this message]
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