From: Matthew Jacob <mjacob@feral.com>
To: James Bottomley <James.Bottomley@steeleye.com>
Cc: "Justin T. Gibbs" <gibbs@scsiguy.com>,
Andrew Morton <akpm@digeo.com>, Jens Axboe <axboe@suse.de>,
"Pedro M. Rodrigues" <pmanuel@myrealbox.com>,
Mathieu Chouquet-Stringer <mathieu@newview.com>,
linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Warning - running *really* short on DMA buffers while doingfiletransfers
Date: Fri, 27 Sep 2002 14:18:12 -0700 (PDT) [thread overview]
Message-ID: <Pine.BSF.4.21.0209271417260.22542-100000@beppo> (raw)
In-Reply-To: <200209272113.g8RLD1420775@localhost.localdomain>
>
> Linux is perfectly happy just to have you return 1 in queuecommand if the
> device won't accept the tag. The can_queue parameter represents the maximum
> number of outstanding commands the mid-layer will ever send. The mid-layer is
> happy to re-queue I/O below this limit if it cannot be accepted by the drive.
> In fact, that's more or less what queue plugging is about.
>
> The only problem occurs if you return 1 from queuecommand with no other
> outstanding I/O for the device.
Duh. There had been race conditions in the past which caused all of us
HBA writers to in fact start swalloing things like QFULL and maintaining
internal queues.
>
> There should be no reason in 2.5 for a driver to have to implement an internal
> queue.
That'd be swell.
next prev parent reply other threads:[~2002-09-27 21:13 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-09-26 3:27 Warning - running *really* short on DMA buffers while doing file transfers Mathieu Chouquet-Stringer
2002-09-26 6:14 ` Jens Axboe
2002-09-26 7:04 ` Pedro M. Rodrigues
2002-09-26 15:31 ` Justin T. Gibbs
2002-09-27 6:13 ` Jens Axboe
2002-09-27 6:33 ` Matthew Jacob
2002-09-27 6:36 ` Jens Axboe
2002-09-27 6:50 ` Matthew Jacob
2002-09-27 6:56 ` Jens Axboe
2002-09-27 7:18 ` Matthew Jacob
2002-09-27 7:24 ` Jens Axboe
2002-09-27 7:29 ` Matthew Jacob
2002-09-27 7:34 ` Matthew Jacob
2002-09-27 7:45 ` Jens Axboe
2002-09-27 8:37 ` Matthew Jacob
2002-09-27 10:25 ` Jens Axboe
2002-09-27 12:18 ` Matthew Jacob
2002-09-27 12:54 ` Jens Axboe
2002-09-27 13:30 ` Justin T. Gibbs
2002-09-27 14:26 ` James Bottomley
2002-09-27 14:33 ` Jens Axboe
2002-09-27 16:26 ` Justin T. Gibbs
2002-09-27 17:21 ` James Bottomley
2002-09-27 18:56 ` Justin T. Gibbs
2002-09-27 19:07 ` Warning - running *really* short on DMA buffers while doingfile transfers Andrew Morton
2002-09-27 19:16 ` Justin T. Gibbs
2002-09-27 19:36 ` Warning - running *really* short on DMA buffers while doingfiletransfers Andrew Morton
2002-09-27 19:52 ` Justin T. Gibbs
2002-09-27 21:13 ` James Bottomley
2002-09-27 21:18 ` Matthew Jacob [this message]
2002-09-27 21:23 ` James Bottomley
2002-09-27 21:29 ` Justin T. Gibbs
2002-09-27 21:32 ` Matthew Jacob
2002-09-27 22:08 ` Mike Anderson
2002-09-30 23:49 ` Doug Ledford
2002-09-27 21:28 ` Justin T. Gibbs
2002-09-28 15:52 ` James Bottomley
2002-09-28 23:25 ` Luben Tuikov
2002-09-29 2:48 ` James Bottomley
2002-09-30 8:34 ` Jens Axboe
2002-09-29 4:00 ` Justin T. Gibbs
2002-09-29 15:45 ` James Bottomley
2002-09-29 16:49 ` [ getting OT ] " Matthew Jacob
2002-09-30 19:06 ` Luben Tuikov
2002-09-30 23:54 ` Doug Ledford
2002-09-27 19:58 ` Andrew Morton
2002-09-27 20:58 ` Warning - running *really* short on DMA buffers while doing file transfers Justin T. Gibbs
2002-09-27 21:38 ` Patrick Mansfield
2002-09-27 22:08 ` Justin T. Gibbs
2002-09-27 22:28 ` Patrick Mansfield
2002-09-27 22:48 ` Justin T. Gibbs
2002-09-27 18:59 ` Warning - running *really* short on DMA buffers while doingfile transfers Andrew Morton
2002-09-27 14:30 ` Warning - running *really* short on DMA buffers while doing file transfers Jens Axboe
2002-09-27 17:19 ` Justin T. Gibbs
2002-09-27 18:29 ` Rik van Riel
2002-09-27 14:56 ` Rik van Riel
2002-09-27 15:34 ` Matthew Jacob
2002-09-27 15:37 ` Jens Axboe
2002-09-27 17:20 ` Justin T. Gibbs
2002-09-27 12:28 ` Pedro M. Rodrigues
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