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From: "Van Maren, Kevin" <kevin.vanmaren@unisys.com>
To: "'Andrew Morton'" <akpm@zip.com.au>
Cc: "'linux-kernel@vger.kernel.org'" <linux-kernel@vger.kernel.org>
Subject: RE: The cause of the "VM" performance problem with 2.4.X
Date: Thu, 23 Aug 2001 12:26:40 -0500
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I did a "mkfs" on a "md" of 3 8-disk "md"s (24 disk md).  So no
lock contention, and only one "dev" to match, right?  [Try to
avoid the problem.]

getblk was holding the lru_list_lock lock 86% of the time.

Was averaging about 25,000 blocks/sec to the disks (vmstat),
but it was often 200,000 over 2 seconds, then 5 seconds idle,
etc.  Disk lights didn't come on much (but they all blinked
nicely in sync).

I'll try your patch out and run individual disks again.

Kevin