android_kernel_xiaomi_sm8450/include/linux/pageblock-flags.h
Mel Gorman 64c5e135bf don't group high order atomic allocations
Grouping high-order atomic allocations together was intended to allow
bursty users of atomic allocations to work such as e1000 in situations
where their preallocated buffers were depleted.  This did not work in at
least one case with a wireless network adapter needing order-1 allocations
frequently.  To resolve that, the free pages used for min_free_kbytes were
moved to separate contiguous blocks with the patch
bias-the-location-of-pages-freed-for-min_free_kbytes-in-the-same-max_order_nr_pages-blocks.

It is felt that keeping the free pages in the same contiguous blocks should
be sufficient for bursty short-lived high-order atomic allocations to
succeed, maybe even with the e1000.  Even if there is a failure, increasing
the value of min_free_kbytes will free pages as contiguous bloks in
contrast to the standard buddy allocator which makes no attempt to keep the
minimum number of free pages contiguous.

This patch backs out grouping high order atomic allocations together to
determine if it is really needed or not.  If a new report comes in about
high-order atomic allocations failing, the feature can be reintroduced to
determine if it fixes the problem or not.  As a side-effect, this patch
reduces by 1 the number of bits required to track the mobility type of
pages within a MAX_ORDER_NR_PAGES block.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Andy Whitcroft <apw@shadowen.org>
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

53 lines
1.8 KiB
C

/*
* Macros for manipulating and testing flags related to a
* MAX_ORDER_NR_PAGES block 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
};
/* 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 */