aha/include/linux/pageblock-flags.h
Mel Gorman d9c2340052 Do not depend on MAX_ORDER when grouping pages by mobility
Currently mobility grouping works at the MAX_ORDER_NR_PAGES level.  This makes
sense for the majority of users where this is also the huge page size.
However, on platforms like ia64 where the huge page size is runtime
configurable it is desirable to group at a lower order.  On x86_64 and
occasionally on x86, the hugepage size may not always be MAX_ORDER_NR_PAGES.

This patch groups pages together based on the value of HUGETLB_PAGE_ORDER.  It
uses a compile-time constant if possible and a variable where the huge page
size is runtime configurable.

It is assumed that grouping should be done at the lowest sensible order and
that the user would not want to override this.  If this is not true,
page_block order could be forced to a variable initialised via a boot-time
kernel parameter.

One potential issue with this patch is that IA64 now parses hugepagesz with
early_param() instead of __setup().  __setup() is called after the memory
allocator has been initialised and the pageblock bitmaps already setup.  In
tests on one IA64 there did not seem to be any problem with using
early_param() and in fact may be more correct as it guarantees the parameter
is handled before the parsing of hugepages=.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Andy Whitcroft <apw@shadowen.org>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 09:43:00 -07:00

75 lines
2.3 KiB
C

/*
* Macros for manipulating and testing flags related to a
* pageblock_nr_pages number of pages.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation version 2 of the License
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) IBM Corporation, 2006
*
* Original author, Mel Gorman
* Major cleanups and reduction of bit operations, Andy Whitcroft
*/
#ifndef PAGEBLOCK_FLAGS_H
#define PAGEBLOCK_FLAGS_H
#include <linux/types.h>
/* Macro to aid the definition of ranges of bits */
#define PB_range(name, required_bits) \
name, name ## _end = (name + required_bits) - 1
/* Bit indices that affect a whole block of pages */
enum pageblock_bits {
PB_range(PB_migrate, 2), /* 2 bits required for migrate types */
NR_PAGEBLOCK_BITS
};
#ifdef CONFIG_HUGETLB_PAGE
#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
/* Huge page sizes are variable */
extern int pageblock_order;
#else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
/* Huge pages are a constant size */
#define pageblock_order HUGETLB_PAGE_ORDER
#endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
#else /* CONFIG_HUGETLB_PAGE */
/* If huge pages are not used, group by MAX_ORDER_NR_PAGES */
#define pageblock_order (MAX_ORDER-1)
#endif /* CONFIG_HUGETLB_PAGE */
#define pageblock_nr_pages (1UL << pageblock_order)
/* Forward declaration */
struct page;
/* Declarations for getting and setting flags. See mm/page_alloc.c */
unsigned long get_pageblock_flags_group(struct page *page,
int start_bitidx, int end_bitidx);
void set_pageblock_flags_group(struct page *page, unsigned long flags,
int start_bitidx, int end_bitidx);
#define get_pageblock_flags(page) \
get_pageblock_flags_group(page, 0, NR_PAGEBLOCK_BITS-1)
#define set_pageblock_flags(page) \
set_pageblock_flags_group(page, 0, NR_PAGEBLOCK_BITS-1)
#endif /* PAGEBLOCK_FLAGS_H */