From: James Bottomley <James.Bottomley@SteelEye.com>
To: Jens Axboe <axboe@suse.de>
Cc: Alan Stern <stern@rowland.harvard.edu>,
Pat LaVarre <p.lavarre@ieee.org>,
SCSI development list <linux-scsi@vger.kernel.org>
Subject: Re: bytes/CDB of SCSI pass thru grossly limited maybe
Date: 28 Aug 2004 14:20:53 -0400 [thread overview]
Message-ID: <1093717255.3682.13.camel@mulgrave> (raw)
In-Reply-To: <20040828175547.GA8339@suse.de>
On Sat, 2004-08-28 at 13:55, Jens Axboe wrote:
> Probably bio and SCSI should use a unified MAX_PAGES define, there's not
> much point in bio setting up a 256 page bio_io_vec slab and mempool, if
> noone can use it.
Sure, ours is SCSI_MAX_PHYS_SEGMENTS ... by default, we just use
MAX_PHYS_SEGMENTS from the bio headers for this, which is 128, we could
set this to BIO_MAX_PAGES, sure.
We allow values of 32,64,128 and 256 (the smaller ones were for tiny
systems with SCSI stacks), the largest one for SGI/Qlogic.
However, I did ask the IBM spearker at OLS who was doing the elevator
analysis to retry with 256 instead of 128, and he reported no difference
within error, so I don't think there's much evidence that 256 actually
does anything useful (other than consume a bit of spare memory).
James
next prev parent reply other threads:[~2004-08-28 18:20 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <A8E06BE4-F7BA-11D8-AC6B-00039398BB5E@ieee.org>
[not found] ` <Pine.LNX.4.44L0 .0408271100590.1238-100000@ida.rowland.org>
2004-08-27 15:09 ` bytes/CDB of SCSI pass thru grossly limited maybe Alan Stern
2004-08-28 14:31 ` Jens Axboe
2004-08-28 15:14 ` Alan Stern
2004-08-28 15:36 ` Jens Axboe
2004-08-28 17:51 ` James Bottomley
2004-08-28 17:55 ` Jens Axboe
2004-08-28 18:20 ` James Bottomley [this message]
2004-08-28 18:41 ` Jens Axboe
2004-08-29 13:34 ` James Bottomley
2004-08-29 13:45 ` Jens Axboe
2004-08-30 18:15 ` Pat LaVarre
2004-09-01 15:20 ` Pat LaVarre
2004-07-30 23:04 Pat LaVarre
2004-07-31 14:12 ` Jens Axboe
2004-08-16 17:55 ` Pat LaVarre
2004-08-17 18:07 ` Pat LaVarre
2004-08-23 15:46 ` Jens Axboe
2004-08-23 16:05 ` Pat LaVarre
2004-08-23 17:08 ` Jens Axboe
2004-08-23 17:28 ` Pat LaVarre
2004-08-23 18:17 ` Jens Axboe
2004-08-26 23:20 ` Pat LaVarre
2004-08-23 16:06 ` Jeff Garzik
2004-08-23 17:05 ` Pat LaVarre
2004-08-23 18:48 ` Luben Tuikov
2004-08-23 19:06 ` Jeff Garzik
2004-08-23 19:14 ` Luben Tuikov
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