tree b3f682ce8df89edb9740fdd5c178df5accc49736
parent 2e9b367c2273ed21c9852a04d90944d472c4f3e6
author Andrea Arcangeli <andrea@suse.de> 1130635008 -0700
committer Linus Torvalds <torvalds@g5.osdl.org> 1130647243 -0700

[PATCH] .text page fault SMP scalability optimization

We had a problem on ppc64 where with more than 4 threads a large system
wouldn't scale well while faulting in the .text (most of the time was spent
in the kernel despite it was an userland compute intensive app).  The
reason is the useless overwrite of the same pte from all cpu.

I fixed it this way (verified on an older kernel but the forward port is
almost identical).  This will benefit all archs not just ppc64.

Signed-off-by: Andrea Arcangeli <andrea@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>