From: Ingo Molnar <mingo@elte.hu>
Date: Wed, 25 Feb 2009 07:22:20 +0000 (+0100)
Subject: x86: usercopy: check for total size when deciding non-temporal cutoff
X-Git-Tag: v2.6.30-rc1~211^2~40^5~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=95108fa34a83ffd97e0af959e4b28d7c62008781;p=pandora-kernel.git

x86: usercopy: check for total size when deciding non-temporal cutoff

Impact: make more types of copies non-temporal

This change makes the following simple fix:

  30d697f: x86: fix performance regression in write() syscall

A bit more sophisticated: we check the 'total' number of bytes
written to decide whether to copy in a cached or a non-temporal
way.

This will for example cause the tail (modulo 4096 bytes) chunk
of a large write() to be non-temporal too - not just the page-sized
chunks.

Cc: Salman Qazi <sqazi@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

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