From: Jens Axboe <jens.axboe@oracle.com>
To: Tejun Heo <tj@kernel.org>
Cc: bharrosh@panasas.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/8] bio: actually inline inline bvecs into bio
Date: Wed, 1 Apr 2009 14:47:09 +0200 [thread overview]
Message-ID: <20090401124709.GG5178@kernel.dk> (raw)
In-Reply-To: <1238583884-13517-5-git-send-email-tj@kernel.org>
On Wed, Apr 01 2009, Tejun Heo wrote:
> Impact: cleanup
>
> BIO_INLINE_VECS bvecs are inlined into bio to avoid bvec allocation
> for small transfers. This was achieved by declaring zero sized bvec
> array at the end of bio and allocating bio with extra bytes at the
> end. As BIO_INLINE_VECS is constant, there is no reason to do this
> allocation trick. This patch simply defines BIO_INLINE_VECS sized
> bvec array at the end. This will help fixing bio_kmalloc().
I don't like this, it's much nicer to do it with a zero sized array. If
you don't need a bio_vec, then you don't consume the extra space. I
guess for that to really work, we'd need one more slab and mempool
though. At least for non-stack bio's. I also fear that direct uses of
->bi_inline_vecs[] will then crop up, making it harder to go back.
--
Jens Axboe
next prev parent reply other threads:[~2009-04-01 12:47 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-01 11:04 [GIT PATCHSET block#for-linus] block: blk-map related fixes Tejun Heo
2009-04-01 11:04 ` [PATCH 1/8] scatterlist: make sure sg_miter_next() doesn't return 0 sized mappings Tejun Heo
2009-04-01 11:04 ` [PATCH 2/8] block: fix SG_IO vector request data length handling Tejun Heo
2009-04-01 11:47 ` FUJITA Tomonori
2009-04-01 11:50 ` Jens Axboe
2009-04-01 12:18 ` FUJITA Tomonori
2009-04-01 12:24 ` Jens Axboe
2009-04-01 12:27 ` Tejun Heo
2009-04-01 12:29 ` Jens Axboe
2009-04-01 11:04 ` [PATCH 3/8] block: fix queue bounce limit setting Tejun Heo
2009-04-01 11:04 ` [PATCH 4/8] bio: actually inline inline bvecs into bio Tejun Heo
2009-04-01 12:47 ` Jens Axboe [this message]
2009-04-01 12:55 ` Tejun Heo
2009-04-01 12:59 ` Jens Axboe
2009-04-01 11:04 ` [PATCH 5/8] bio: fix bio_kmalloc() Tejun Heo
2009-04-01 11:04 ` [PATCH 6/8] bio: remove size/segments limit on bio_{copy|map}_{user|kern}*() Tejun Heo
2009-04-01 11:04 ` [PATCH 7/8] blk-map: let blk_rq_map_user_iov() support null mapping Tejun Heo
2009-04-01 11:54 ` FUJITA Tomonori
2009-04-01 12:03 ` Tejun Heo
2009-04-01 11:04 ` [PATCH 8/8] blk-map: reimplement blk_rq_map_user() using blk_rq_map_user_iov() Tejun Heo
2009-04-01 12:44 ` FUJITA Tomonori
2009-04-01 12:50 ` Tejun Heo
2009-04-01 12:59 ` FUJITA Tomonori
2009-04-01 13:03 ` Tejun Heo
2009-04-01 13:10 ` FUJITA Tomonori
2009-04-01 13:17 ` Tejun Heo
2009-04-01 13:18 ` Tejun Heo
2009-04-01 13:22 ` FUJITA Tomonori
2009-04-01 13:28 ` Tejun Heo
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