]> pilppa.com Git - linux-2.6-omap-h63xx.git/commit
define new percpu interface for shared data
authorFenghua Yu <fenghua.yu@intel.com>
Thu, 19 Jul 2007 08:48:12 +0000 (01:48 -0700)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Thu, 19 Jul 2007 17:04:44 +0000 (10:04 -0700)
commit5fb7dc37dc16fbc8b80d81318a582201ef7e280d
tree4d6bb4441ece64380e7186ebadd35ad2f5486f9f
parent3d7e33825d8799115dd2495c9944badd3272a623
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>
26 files changed:
arch/alpha/kernel/vmlinux.lds.S
arch/arm/kernel/vmlinux.lds.S
arch/cris/arch-v32/vmlinux.lds.S
arch/frv/kernel/vmlinux.lds.S
arch/i386/kernel/vmlinux.lds.S
arch/ia64/kernel/vmlinux.lds.S
arch/m32r/kernel/vmlinux.lds.S
arch/mips/kernel/vmlinux.lds.S
arch/parisc/kernel/vmlinux.lds.S
arch/powerpc/kernel/vmlinux.lds.S
arch/ppc/kernel/vmlinux.lds.S
arch/s390/kernel/vmlinux.lds.S
arch/sh/kernel/vmlinux.lds.S
arch/sh64/kernel/vmlinux.lds.S
arch/sparc/kernel/vmlinux.lds.S
arch/sparc64/kernel/vmlinux.lds.S
arch/x86_64/kernel/vmlinux.lds.S
arch/xtensa/kernel/vmlinux.lds.S
include/asm-generic/percpu.h
include/asm-generic/vmlinux.lds.h
include/asm-i386/percpu.h
include/asm-ia64/percpu.h
include/asm-powerpc/percpu.h
include/asm-s390/percpu.h
include/asm-sparc64/percpu.h
include/asm-x86_64/percpu.h