linux-kernel - [PATCH] make MADV_FREE lazily free memory

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Date:	Wed, 11 Apr 2007 00:30:10 -0400
From:	Rik van Riel <riel@...hat.com>
To:	linux-kernel <linux-kernel@...r.kernel.org>
CC:	linux-mm <linux-mm@...ck.org>, Ulrich Drepper <drepper@...hat.com>
Subject: [PATCH] make MADV_FREE lazily free memory

Make it possible for applications to have the kernel free memory
lazily.  This reduces a repeated free/malloc cycle from freeing
pages and allocating them, to just marking them freeable.  If the
application wants to reuse them before the kernel needs the memory,
not even a page fault will happen.

This version has one bugfix over the last one: if a PG_lazyfree
page was found dirty at fork time, we clear the flag in
copy_one_pte().

Ulrich Drepper has test glibc RPMS for this functionality at:

	http://people.redhat.com/drepper/rpms

Because MADV_FREE has not been defined as a fixed number yet,
for the moment MADV_DONTNEED is defined to have the same
functionality.

Any test results of this patch in combination with Ulrich's
test glibc are welcome.

-- 
Politics is the struggle between those who want to make their country
the best in the world, and those who believe it already is.  Each group
calls the other unpatriotic.

View attachment "linux-2.6-madv_free.patch" of type "text/x-patch" (12445 bytes)