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

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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>

...

This commit is contained in:

Ingo Molnar 2009-02-25 08:22:20 +01:00

parent 3255aa2eb6

commit 95108fa34a

1 changed files with 2 additions and 2 deletions

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arch/x86/include/asm/uaccess_64.h

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