]> git.karo-electronics.de Git - karo-tx-linux.git/commit
mm,slub,x86: decouple size of struct page from CONFIG_CMPXCHG_LOCAL
authorHeiko Carstens <heiko.carstens@de.ibm.com>
Thu, 8 Dec 2011 04:41:54 +0000 (15:41 +1100)
committerStephen Rothwell <sfr@canb.auug.org.au>
Tue, 13 Dec 2011 06:43:16 +0000 (17:43 +1100)
commita64f543b8f7acb2034cf02fe505503d80002212f
treed29294b3a83331d51c2ccde1119aa93e280ca3fb
parentca5523eee28094dba2d7d4004ff82262b4bbb56f
mm,slub,x86: decouple size of struct page from CONFIG_CMPXCHG_LOCAL

While implementing cmpxchg_double() on s390 I realized that we don't set
CONFIG_CMPXCHG_LOCAL besides the fact that we have support for it.
However setting that option will increase the size of struct page by eight
bytes on 64 bit, which we certainly do not want.  Also, it doesn't make
sense that a present cpu feature should increase the size of struct page.

Besides that it looks like the dependency to CMPXCHG_LOCAL is wrong and
that it should depend on CMPXCHG_DOUBLE instead.

This patch:

If an architecture supports CMPXCHG_LOCAL this shouldn't result
automatically in larger struct pages if the SLUB allocator is used.
Instead introduce a new config option "HAVE_ALIGNED_STRUCT_PAGE" which can
be selected if a double word aligned struct page is required.  Also update
x86 Kconfig so that it should work as before.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
arch/Kconfig
arch/x86/Kconfig
include/linux/mm_types.h
mm/slub.c