From: Christoph Hellwig <hch@lst.de>
To: Qu Wenruo <quwenruo.btrfs@gmx.com>
Cc: Christoph Hellwig <hch@lst.de>, Qu Wenruo <wqu@suse.com>,
linux-btrfs@vger.kernel.org
Subject: Re: [PATCH v2 4/7] btrfs: introduce new read-repair infrastructure
Date: Thu, 26 May 2022 10:54:02 +0200 [thread overview]
Message-ID: <20220526085402.GA26954@lst.de> (raw)
In-Reply-To: <f18c85ef-ff11-8308-4562-d68d4578d6f4@gmx.com>
On Thu, May 26, 2022 at 04:49:15PM +0800, Qu Wenruo wrote:
>>>> Because that really sucks for the case where the whole I/O fails.
>>>> Which is the common failure scenario.
>>>
>>> But it's just a performance problem, which is not that critical.
>>
>> I'm officially lost now.
>
> Why? If you care so much about the code simplicity, sector-by-sector is
> the best.
> If you care so much about the performance, the latest bitmap is the
> best, no matter if it's the worst checker patter or not.
Because you tell me that handling the most common and important case
in read repair is just a performance issue, which you keep arguing for
micro-optimizing a corner case. And not, for the case of failing a
large bio (which arguably can only happen for buffered I/O at the
moment, but that is another thing to look into) the bitmaps will only
help you for up to 64 sectors. Way better than just doing a single
sector synchronous I/O but not exactly nice while still being a fair
amount of code compared to just doing variable sized synchronous
I/O.
next prev parent reply other threads:[~2022-05-26 8:54 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-25 10:59 [PATCH v2 0/7] btrfs: read-repair rework based on bitmap Qu Wenruo
2022-05-25 10:59 ` [PATCH v2 1/7] btrfs: save the original bi_iter into btrfs_bio for buffered read Qu Wenruo
2022-05-25 10:59 ` [PATCH v2 2/7] btrfs: make repair_io_failure available outside of extent_io.c Qu Wenruo
2022-05-25 10:59 ` [PATCH v2 3/7] btrfs: add a btrfs_map_bio_wait helper Qu Wenruo
2022-05-25 10:59 ` [PATCH v2 4/7] btrfs: introduce new read-repair infrastructure Qu Wenruo
2022-05-26 3:06 ` Qu Wenruo
2022-05-26 7:30 ` Christoph Hellwig
2022-05-26 7:37 ` Qu Wenruo
2022-05-26 7:45 ` Christoph Hellwig
2022-05-26 7:52 ` Qu Wenruo
2022-05-26 8:00 ` Christoph Hellwig
2022-05-26 8:07 ` Qu Wenruo
2022-05-26 8:17 ` Christoph Hellwig
2022-05-26 8:26 ` Qu Wenruo
2022-05-26 8:28 ` Christoph Hellwig
2022-05-26 8:49 ` Qu Wenruo
2022-05-26 8:54 ` Christoph Hellwig [this message]
2022-05-26 9:13 ` Qu Wenruo
2022-05-27 8:10 ` Christoph Hellwig
2022-05-25 10:59 ` [PATCH v2 5/7] btrfs: make buffered read path to use the new read repair infrastructure Qu Wenruo
2022-05-25 10:59 ` [PATCH v2 6/7] btrfs: make direct io " Qu Wenruo
2022-05-25 10:59 ` [PATCH v2 7/7] btrfs: remove io_failure_record infrastructure completely Qu Wenruo
2022-05-25 14:55 ` [PATCH v2 0/7] btrfs: read-repair rework based on bitmap David Sterba
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