From: Christoph Hellwig <hch@lst.de>
To: NeilBrown <neilb@suse.com>
Cc: Shaohua Li <shli@fb.com>,
linux-raid@vger.kernel.org, khlebnikov@yandex-team.ru,
hch@lst.de
Subject: Re: [PATCH 1/5] MD: attach data to each bio
Date: Mon, 13 Feb 2017 08:37:24 +0100 [thread overview]
Message-ID: <20170213073724.GA16666@lst.de> (raw)
In-Reply-To: <87r336tw5l.fsf@notabene.neil.brown.name>
On Fri, Feb 10, 2017 at 05:08:54PM +1100, NeilBrown wrote:
> I must say that I don't really like this approach.
> Temporarily modifying ->bi_private and ->bi_end_io seems
> .... intrusive. I suspect it works, but I wonder if it is really
> robust in the long term.
>
> How about a different approach.. Your main concern with my first patch
> was that it called md_write_start() and md_write_end() much more often,
> and these performed atomic ops on "global" variables, particular
> writes_pending.
>
> We could change writes_pending to a per-cpu array which we only count
> occasionally when needed. As writes_pending is updated often and
> checked rarely, a per-cpu array which is summed on demand seems
> appropriate.
FYI, I much prefer you original approach, it's much closer to how
the rest of the block stack works.
next prev parent reply other threads:[~2017-02-13 7:37 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-07 16:55 [PATCH 0/5] MD: don't abuse bi_phys_segements Shaohua Li
2017-02-07 16:55 ` [PATCH 1/5] MD: attach data to each bio Shaohua Li
2017-02-08 9:07 ` Guoqing Jiang
2017-02-08 5:24 ` Shaohua Li
2017-02-09 0:09 ` Wols Lists
2017-02-10 6:08 ` NeilBrown
2017-02-10 6:47 ` Shaohua Li
2017-02-13 9:49 ` NeilBrown
2017-02-13 18:49 ` Shaohua Li
2017-02-14 2:40 ` NeilBrown
2017-02-13 7:37 ` Christoph Hellwig [this message]
2017-02-13 9:32 ` NeilBrown
2017-02-07 16:55 ` [PATCH 2/5] md/raid5: don't abuse bio->bi_phys_segments Shaohua Li
2017-02-07 16:56 ` [PATCH 3/5] md/raid5: change disk limits Shaohua Li
2017-02-07 16:56 ` [PATCH 4/5] md/raid1: don't abuse bio->bi_phys_segments Shaohua Li
2017-02-07 16:56 ` [PATCH 5/5] md/raid10: " Shaohua Li
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