From: Christoph Hellwig <hch@lst.de>
To: NeilBrown <neilb@suse.com>
Cc: Shaohua Li <shli@kernel.org>, Christoph Hellwig <hch@lst.de>,
linux-raid@vger.kernel.org
Subject: Re: [md PATCH 0/5] Stop using bi_phys_segments as a counter
Date: Wed, 23 Nov 2016 09:45:40 +0100 [thread overview]
Message-ID: <20161123084540.GE16966@lst.de> (raw)
In-Reply-To: <87zikraqxl.fsf@notabene.neil.brown.name>
On Wed, Nov 23, 2016 at 01:08:38PM +1100, NeilBrown wrote:
> For raid1/raid10 we could do a very similar thing. There is an
> awkwardness in raid1 w.r.t waiting for bi_phys_segments to reach 1, but
> that might disappear if Coly's resync changes go through.
> Alternately it might make sense to use bio_split so there is one r1_bio
> per bio.
> I might try the raid10 version and see what it looks like.
For RAID1 reads there already is one r1_bio per bio - in fact I have
a hack that doesn't allocate a r1_bio at all, but that one currently
does not handle reads from degraded arrays at all. Due you remember
why we only mark a leg fail for a given bio instead of on a per-device
or at least per sector-range?
For writes it would make sense to allocate the new bio for each mirror
using a bio_set with front_pad for raid1-specific data, but I haven't
really looked into the details yet.
next prev parent reply other threads:[~2016-11-23 8:45 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-21 1:19 [md PATCH 0/5] Stop using bi_phys_segments as a counter NeilBrown
2016-11-21 1:19 ` [md PATCH 5/5] md/raid5: use bio_inc_remaining() instead of repurposing " NeilBrown
2016-11-21 1:19 ` [md PATCH 3/5] md/raid5: simplfy delaying of writes while metadata is updated NeilBrown
2016-11-21 1:19 ` [md PATCH 4/5] md/raid5: call bio_endio() directly rather than queuing for later NeilBrown
2016-11-21 1:19 ` [md PATCH 2/5] md/raid5: use md_write_start to count stripes, not bios NeilBrown
2016-11-21 1:19 ` [md PATCH 1/5] md: optimize md_write_start() slightly NeilBrown
2016-11-21 2:32 ` [md PATCH 6/5] md/raid5: remove over-loading of ->bi_phys_segments NeilBrown
2016-11-21 14:01 ` [md PATCH 0/5] Stop using bi_phys_segments as a counter Christoph Hellwig
2016-11-21 23:43 ` Shaohua Li
2016-11-22 0:25 ` NeilBrown
2016-11-22 1:02 ` Shaohua Li
2016-11-22 2:19 ` NeilBrown
2016-11-22 8:01 ` Shaohua Li
2016-11-23 2:08 ` NeilBrown
2016-11-23 8:45 ` Christoph Hellwig [this message]
2016-11-24 0:31 ` NeilBrown
2017-02-06 8:56 ` Christoph Hellwig
2017-02-06 21:41 ` Shaohua Li
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