linux-kernel - [PATCH 0/2] x86: fix memory leaks when doing CPU hotplug

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Message-ID: <20080806082400.GC5427@alberich.amd.com>
Date:	Wed, 6 Aug 2008 10:24:00 +0200
From:	Andreas Herrmann <andreas.herrmann3@....com>
To:	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>
CC:	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org
Subject: [PATCH 0/2] x86: fix memory leaks when doing CPU hotplug

Following patches fix two memory leaks with CPU hotplug.
Some per CPU data is allocated each time a CPU is set online.
But this space is never freed.

Usually this memory leak is not a big deal (for normal CPU hotplug usage).
But during stress tests with lots of CPU offline/online cycles this
really matters.

The entire leak is 40K (10 pages) for each offline/online cycle per
CPU.  I've verified both fixes performing more than 90000 CPU
offline/online cycles.

This is not a regression but I think it's still 2.6.27 material.
Please apply.

Regards,

Andreas

BTW, there is still a leak of about 600 bytes per offline/online cycle
per CPU -- according to slabinfo this might be sysfs related. The most
suspicious entries are:

Name                   Objects Objsize    Space Slabs/Part/Cpu  O/S O %Fr %Ef Flg
sysfs_dir_cache         266085      80    41.9M      10235/4/0   26 0   0  50 PZFU
kmalloc-8               130870       8    10.5M       2568/5/0   51 0   0   9 PZFU

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