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From: Theodore Tso <tytso@MIT.EDU>
To: Arjan van de Ven <arjan@infradead.org>
Cc: akpm@linux-foundation.org, jens.axboe@oracle.com,
	linux-kernel@vger.kernel.org
Subject: Re: PATCH] fix potential latency issues in JBD's journal code
Date: Sun, 6 Jul 2008 00:15:02 -0400	[thread overview]
Message-ID: <20080706041502.GB21990@mit.edu> (raw)
In-Reply-To: <20080704192929.2c4dd4ca@infradead.org>

On Fri, Jul 04, 2008 at 07:29:29PM -0700, Arjan van de Ven wrote:
> @@ -165,7 +165,7 @@ static void journal_do_submit_data(struct buffer_head **wbuf, int bufs)
>  	for (i = 0; i < bufs; i++) {
>  		wbuf[i]->b_end_io = end_buffer_write_sync;
>  		/* We use-up our safety reference in submit_bh() */
> -		submit_bh(WRITE, wbuf[i]);
> +		submit_bh(WRITE_SYNC, wbuf[i]);
>  	}
>  }

So I started looking at this patch more closely when trying to
replicate it for ext4.  Don't you want to only use WRITE_SYNC() only
for the very last time in the loop?  Otherwise you end up unplugging
the queue after each bufferhead, which wouldn't be a good thing, right?

    	  	     		       		- Ted

  parent reply	other threads:[~2008-07-06  4:16 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-07-05  2:29 PATCH] fix potential latency issues in JBD's journal code Arjan van de Ven
2008-07-05  5:00 ` Arjan van de Ven
2008-07-05 14:13 ` Theodore Tso
2008-07-05 15:18   ` Arjan van de Ven
2008-07-06  4:15 ` Theodore Tso [this message]
2008-07-06  5:30   ` Arjan van de Ven
2008-07-06 12:20     ` Theodore Tso

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