linux/arch
Fenghua Yu 5fb7dc37dc define new percpu interface for shared data
per cpu data section contains two types of data.  One set which is
exclusively accessed by the local cpu and the other set which is per cpu,
but also shared by remote cpus.  In the current kernel, these two sets are
not clearely separated out.  This can potentially cause the same data
cacheline shared between the two sets of data, which will result in
unnecessary bouncing of the cacheline between cpus.

One way to fix the problem is to cacheline align the remotely accessed per
cpu data, both at the beginning and at the end.  Because of the padding at
both ends, this will likely cause some memory wastage and also the
interface to achieve this is not clean.

This patch:

Moves the remotely accessed per cpu data (which is currently marked
as ____cacheline_aligned_in_smp) into a different section, where all the data
elements are cacheline aligned. And as such, this differentiates the local
only data and remotely accessed data cleanly.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: <linux-arch@vger.kernel.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19 10:04:44 -07:00
..
alpha define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
arm define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
arm26 mm: fault feedback #2 2007-07-19 10:04:41 -07:00
avr32 mm: fault feedback #2 2007-07-19 10:04:41 -07:00
blackfin
cris define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
frv define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
h8300 PTRACE_POKEDATA consolidation 2007-07-17 10:23:03 -07:00
i386 define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
ia64 define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
m32r define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
m68k mm: fault feedback #2 2007-07-19 10:04:41 -07:00
m68knommu PTRACE_POKEDATA consolidation 2007-07-17 10:23:03 -07:00
mips define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
parisc define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
powerpc define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
ppc define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
s390 define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
sh define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
sh64 define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
sparc define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
sparc64 define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
um mm: fault feedback #2 2007-07-19 10:04:41 -07:00
v850 PTRACE_POKEDATA consolidation 2007-07-17 10:23:03 -07:00
x86_64 define new percpu interface for shared data 2007-07-19 10:04:44 -07:00
xtensa define new percpu interface for shared data 2007-07-19 10:04:44 -07:00