linux-kernel - [PATCH 0/2] x86: Speed up ioremap operations

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 27 Aug 2014 17:59:27 -0500
From:	Mike Travis <travis@....com>
To:	mingo@...hat.com, tglx@...utronix.de, hpa@...or.com
Cc:	akpm@...ux-foundation.org, msalter@...hat.com, dyoung@...hat.com,
	riel@...hat.com, peterz@...radead.org, mgorman@...e.de,
	linux-kernel@...r.kernel.org, x86@...nel.org, linux-mm@...ck.org
Subject: [PATCH 0/2] x86: Speed up ioremap operations

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.

-- 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/