Commit d239171e authored Jun 16, 2009 by Mel Gorman Committed by Linus Torvalds Jun 16, 2009

page allocator: replace __alloc_pages_internal() with __alloc_pages_nodemask()



The start of a large patch series to clean up and optimise the page
allocator.

The performance improvements are in a wide range depending on the exact
machine but the results I've seen so fair are approximately;

kernbench:	0	to	 0.12% (elapsed time)
		0.49%	to	 3.20% (sys time)
aim9:		-4%	to	30% (for page_test and brk_test)
tbench:		-1%	to	 4%
hackbench:	-2.5%	to	 3.45% (mostly within the noise though)
netperf-udp	-1.34%  to	 4.06% (varies between machines a bit)
netperf-tcp	-0.44%  to	 5.22% (varies between machines a bit)

I haven't sysbench figures at hand, but previously they were within the
-0.5% to 2% range.

On netperf, the client and server were bound to opposite number CPUs to
maximise the problems with cache line bouncing of the struct pages so I
expect different people to report different results for netperf depending
on their exact machine and how they ran the test (different machines, same
cpus client/server, shared cache but two threads client/server, different
socket client/server etc).

I also measured the vmlinux sizes for a single x86-based config with
CONFIG_DEBUG_INFO enabled but not CONFIG_DEBUG_VM.  The core of the
.config is based on the Debian Lenny kernel config so I expect it to be
reasonably typical.

This patch:

__alloc_pages_internal is the core page allocator function but essentially
it is an alias of __alloc_pages_nodemask.  Naming a publicly available and
exported function "internal" is also a big ugly.  This patch renames
__alloc_pages_internal() to __alloc_pages_nodemask() and deletes the old
nodemask function.

Warning - This patch renames an exported symbol.  No kernel driver is
affected by external drivers calling __alloc_pages_internal() should
change the call to __alloc_pages_nodemask() without any alteration of
parameters.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 6c0db466

include/linux/gfp.h

+2 −10

Original line number	Diff line number	Diff line
		@@ -172,24 +172,16 @@ static inline void arch_alloc_page(struct page *page, int order) { }
		#endif

		struct page *
		__alloc_pages_internal(gfp_t gfp_mask, unsigned int order,
		__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
		struct zonelist zonelist, nodemask_t nodemask);

		static inline struct page *
		__alloc_pages(gfp_t gfp_mask, unsigned int order,
		struct zonelist *zonelist)
		{
		return __alloc_pages_internal(gfp_mask, order, zonelist, NULL);
		return __alloc_pages_nodemask(gfp_mask, order, zonelist, NULL);
		}

		static inline struct page *
		__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
		struct zonelist zonelist, nodemask_t nodemask)
		{
		return __alloc_pages_internal(gfp_mask, order, zonelist, nodemask);
		}


		static inline struct page *alloc_pages_node(int nid, gfp_t gfp_mask,
		unsigned int order)
		{

mm/page_alloc.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1458,7 +1458,7 @@ get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
		* This is the 'heart' of the zoned buddy allocator.
		*/
		struct page *
		__alloc_pages_internal(gfp_t gfp_mask, unsigned int order,
		__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
		struct zonelist zonelist, nodemask_t nodemask)
		{
		const gfp_t wait = gfp_mask & __GFP_WAIT;
		@@ -1667,7 +1667,7 @@ __alloc_pages_internal(gfp_t gfp_mask, unsigned int order,
		got_pg:
		return page;
		}
		EXPORT_SYMBOL(__alloc_pages_internal);
		EXPORT_SYMBOL(__alloc_pages_nodemask);

		/*
		* Common helper functions.