From: Mike Travis <travis@sgi.com>
To: mingo@redhat.com, tglx@linutronix.de, hpa@zytor.com
Cc: akpm@linux-foundation.org, msalter@redhat.com, dyoung@redhat.com,
riel@redhat.com, peterz@infradead.org, mgorman@suse.de,
linux-kernel@vger.kernel.org, x86@kernel.org, linux-mm@kvack.org
Subject: [PATCH 0/2] x86: Speed up ioremap operations
Date: Fri, 29 Aug 2014 14:16:47 -0500 [thread overview]
Message-ID: <20140829191647.364032240@asylum.americas.sgi.com> (raw)
We have a large university system in the UK that is experiencing
very long delays modprobing the driver for a specific I/O device.
The delay is from 8-10 minutes per device and there are 31 devices
in the system. This 4 to 5 hour delay in starting up those I/O
devices is very much a burden on the customer.
There are two causes for requiring a restart/reload of the drivers.
First is periodic preventive maintenance (PM) and the second is if
any of the devices experience a fatal error. Both of these trigger
this excessively long delay in bringing the system back up to full
capability.
The problem was tracked down to a very slow IOREMAP operation and
the excessively long ioresource lookup to insure that the user is
not attempting to ioremap RAM. These patches provide a speed up
to that function.
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next reply other threads:[~2014-08-29 19:16 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-29 19:16 Mike Travis [this message]
2014-08-29 19:16 ` [PATCH 1/2] x86: Optimize resource lookups for ioremap Mike Travis
2014-08-29 19:16 ` [PATCH 2/2] x86: Use optimized ioresource lookup in ioremap function Mike Travis
-- strict thread matches above, loose matches on Subject: below --
2014-08-29 19:53 [PATCH 0/2] x86: Speed up ioremap operations Mike Travis
2014-08-29 20:16 ` Andrew Morton
2014-08-29 20:44 ` Mike Travis
2014-08-29 20:52 ` Andrew Morton
2014-08-29 22:31 ` Greg KH
2014-08-27 22:59 Mike Travis
2014-08-27 23:06 ` Andrew Morton
2014-08-27 23:15 ` Mike Travis
2014-08-27 23:20 ` Andrew Morton
2014-08-27 23:30 ` Mike Travis
2014-08-28 6:48 ` Ingo Molnar
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