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From: corbet@lwn.net (Jonathan Corbet)
To: Daniel Phillips <phillips@phunq.net>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC] [PATCH] A clean approach to writeout throttling
Date: Mon, 10 Dec 2007 14:31:52 -0700	[thread overview]
Message-ID: <25797.1197322312@lwn.net> (raw)
In-Reply-To: Your message of "Wed, 05 Dec 2007 16:03:01 PST." <200712051603.02183.phillips@phunq.net>

Hey, Daniel,

I'm just getting around to looking at this.  One thing jumped out at me:

> +	if (bio->bi_throttle) {
> +		struct request_queue *q = bio->bi_queue;
> +		bio->bi_throttle = 0; /* or detect multiple endio and err? */
> +		atomic_add(bio->bi_throttle, &q->available);
> +		wake_up(&q->throttle_wait);
> +	}

I'm feeling like I must be really dumb, but...how can that possibly
work?  You're zeroing >bi_throttle before adding it back into
q->available, so the latter will never increase...

jon

  parent reply	other threads:[~2007-12-10 21:32 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-12-06  0:03 [RFC] [PATCH] A clean approach to writeout throttling Daniel Phillips
2007-12-06  1:24 ` Andrew Morton
2007-12-06  6:21   ` Daniel Phillips
2007-12-06  7:31     ` Andrew Morton
2007-12-06  9:48       ` Daniel Phillips
2007-12-06 11:55         ` Andrew Morton
2007-12-06 15:52           ` Rik van Riel
2007-12-06 17:34             ` Andrew Morton
2007-12-06 17:48               ` Rik van Riel
2007-12-06 20:04           ` Daniel Phillips
2007-12-06 20:27             ` Andrew Morton
2007-12-06 21:27               ` Daniel Phillips
2007-12-06 21:53     ` Bill Davidsen
2007-12-07  0:04       ` Daniel Phillips
2007-12-07  0:29         ` Andrew Morton
2007-12-07  7:13           ` Daniel Phillips
2007-12-10  9:20             ` Daniel Phillips
2007-12-10 10:47 ` Jens Axboe
2007-12-10 11:23   ` [RFC] [PATCH] A clean aEvgeniy pproach " Daniel Phillips
2007-12-10 11:41     ` Jens Axboe
2007-12-10 12:13       ` Daniel Phillips
2007-12-10 12:16         ` Jens Axboe
2007-12-10 12:27           ` Daniel Phillips
2007-12-10 12:32             ` Jens Axboe
2007-12-10 13:04               ` Daniel Phillips
2007-12-10 13:19                 ` Jens Axboe
2007-12-10 13:26                   ` Daniel Phillips
2007-12-10 13:30                     ` Jens Axboe
2007-12-10 13:43                       ` Daniel Phillips
2007-12-10 13:53                         ` Jens Axboe
2007-12-10 14:17                           ` Daniel Phillips
2007-12-11 13:15                             ` Jens Axboe
2007-12-11 19:38                               ` Daniel Phillips
2007-12-11 20:01                                 ` Jens Axboe
2007-12-11 20:11                                   ` Daniel Phillips
2007-12-11 20:07                               ` Daniel Phillips
2007-12-10 11:33   ` [RFC] [PATCH] A clean approach " Daniel Phillips
2007-12-10 21:31 ` Jonathan Corbet [this message]
2007-12-10 22:06   ` Pekka Enberg
2007-12-11  4:21   ` Daniel Phillips

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