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linux-next/include/linux/gfp.h
Mel Gorman 2a1e274acf Create the ZONE_MOVABLE zone 
The following 8 patches against 2.6.20-mm2 create a zone called ZONE_MOVABLE
that is only usable by allocations that specify both __GFP_HIGHMEM and
__GFP_MOVABLE.  This has the effect of keeping all non-movable pages within a
single memory partition while allowing movable allocations to be satisfied
from either partition.  The patches may be applied with the list-based
anti-fragmentation patches that groups pages together based on mobility.

The size of the zone is determined by a kernelcore= parameter specified at
boot-time.  This specifies how much memory is usable by non-movable
allocations and the remainder is used for ZONE_MOVABLE.  Any range of pages
within ZONE_MOVABLE can be released by migrating the pages or by reclaiming.

When selecting a zone to take pages from for ZONE_MOVABLE, there are two
things to consider.  First, only memory from the highest populated zone is
used for ZONE_MOVABLE.  On the x86, this is probably going to be ZONE_HIGHMEM
but it would be ZONE_DMA on ppc64 or possibly ZONE_DMA32 on x86_64.  Second,
the amount of memory usable by the kernel will be spread evenly throughout
NUMA nodes where possible.  If the nodes are not of equal size, the amount of
memory usable by the kernel on some nodes may be greater than others.

By default, the zone is not as useful for hugetlb allocations because they are
pinned and non-migratable (currently at least).  A sysctl is provided that
allows huge pages to be allocated from that zone.  This means that the huge
page pool can be resized to the size of ZONE_MOVABLE during the lifetime of
the system assuming that pages are not mlocked.  Despite huge pages being
non-movable, we do not introduce additional external fragmentation of note as
huge pages are always the largest contiguous block we care about.

Credit goes to Andy Whitcroft for catching a large variety of problems during
review of the patches.

This patch creates an additional zone, ZONE_MOVABLE.  This zone is only usable
by allocations which specify both __GFP_HIGHMEM and __GFP_MOVABLE.  Hot-added
memory continues to be placed in their existing destination as there is no
mechanism to redirect them to a specific zone.

[y-goto@jp.fujitsu.com: Fix section mismatch of memory hotplug related code]
[akpm@linux-foundation.org: various fixes]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 10:22:59 -07:00

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#ifndef __LINUX_GFP_H
#define __LINUX_GFP_H
#include <linux/mmzone.h>
#include <linux/stddef.h>
#include <linux/linkage.h>
struct vm_area_struct;
/*
* GFP bitmasks..
*
* Zone modifiers (see linux/mmzone.h - low three bits)
*
* Do not put any conditional on these. If necessary modify the definitions
* without the underscores and use the consistently. The definitions here may
* be used in bit comparisons.
*/
#define __GFP_DMA ((__force gfp_t)0x01u)
#define __GFP_HIGHMEM ((__force gfp_t)0x02u)
#define __GFP_DMA32 ((__force gfp_t)0x04u)
/*
* Action modifiers - doesn't change the zoning
*
* __GFP_REPEAT: Try hard to allocate the memory, but the allocation attempt
* _might_ fail. This depends upon the particular VM implementation.
*
* __GFP_NOFAIL: The VM implementation _must_ retry infinitely: the caller
* cannot handle allocation failures.
*
* __GFP_NORETRY: The VM implementation must not retry indefinitely.
*
* __GFP_MOVABLE: Flag that this page will be movable by the page migration
* mechanism or reclaimed
*/
#define __GFP_WAIT ((__force gfp_t)0x10u) /* Can wait and reschedule? */
#define __GFP_HIGH ((__force gfp_t)0x20u) /* Should access emergency pools? */
#define __GFP_IO ((__force gfp_t)0x40u) /* Can start physical IO? */
#define __GFP_FS ((__force gfp_t)0x80u) /* Can call down to low-level FS? */
#define __GFP_COLD ((__force gfp_t)0x100u) /* Cache-cold page required */
#define __GFP_NOWARN ((__force gfp_t)0x200u) /* Suppress page allocation failure warning */
#define __GFP_REPEAT ((__force gfp_t)0x400u) /* Retry the allocation. Might fail */
#define __GFP_NOFAIL ((__force gfp_t)0x800u) /* Retry for ever. Cannot fail */
#define __GFP_NORETRY ((__force gfp_t)0x1000u)/* Do not retry. Might fail */
#define __GFP_COMP ((__force gfp_t)0x4000u)/* Add compound page metadata */
#define __GFP_ZERO ((__force gfp_t)0x8000u)/* Return zeroed page on success */
#define __GFP_NOMEMALLOC ((__force gfp_t)0x10000u) /* Don't use emergency reserves */
#define __GFP_HARDWALL ((__force gfp_t)0x20000u) /* Enforce hardwall cpuset memory allocs */
#define __GFP_THISNODE ((__force gfp_t)0x40000u)/* No fallback, no policies */
#define __GFP_MOVABLE ((__force gfp_t)0x80000u) /* Page is movable */
#define __GFP_BITS_SHIFT 20 /* Room for 20 __GFP_FOO bits */
#define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
/* if you forget to add the bitmask here kernel will crash, period */
#define GFP_LEVEL_MASK (__GFP_WAIT|__GFP_HIGH|__GFP_IO|__GFP_FS| \
__GFP_COLD|__GFP_NOWARN|__GFP_REPEAT| \
__GFP_NOFAIL|__GFP_NORETRY|__GFP_COMP| \
__GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_THISNODE| \
__GFP_MOVABLE)
/* This equals 0, but use constants in case they ever change */
#define GFP_NOWAIT (GFP_ATOMIC & ~__GFP_HIGH)
/* GFP_ATOMIC means both !wait (__GFP_WAIT not set) and use emergency pool */
#define GFP_ATOMIC (__GFP_HIGH)
#define GFP_NOIO (__GFP_WAIT)
#define GFP_NOFS (__GFP_WAIT | __GFP_IO)
#define GFP_KERNEL (__GFP_WAIT | __GFP_IO | __GFP_FS)
#define GFP_USER (__GFP_WAIT | __GFP_IO | __GFP_FS | __GFP_HARDWALL)
#define GFP_HIGHUSER (__GFP_WAIT | __GFP_IO | __GFP_FS | __GFP_HARDWALL | \
__GFP_HIGHMEM)
#define GFP_HIGHUSER_MOVABLE (__GFP_WAIT | __GFP_IO | __GFP_FS | \
__GFP_HARDWALL | __GFP_HIGHMEM | \
__GFP_MOVABLE)
#define GFP_NOFS_PAGECACHE (__GFP_WAIT | __GFP_IO | __GFP_MOVABLE)
#define GFP_USER_PAGECACHE (__GFP_WAIT | __GFP_IO | __GFP_FS | \
__GFP_HARDWALL | __GFP_MOVABLE)
#define GFP_HIGHUSER_PAGECACHE (__GFP_WAIT | __GFP_IO | __GFP_FS | \
__GFP_HARDWALL | __GFP_HIGHMEM | \
__GFP_MOVABLE)
#ifdef CONFIG_NUMA
#define GFP_THISNODE (__GFP_THISNODE | __GFP_NOWARN | __GFP_NORETRY)
#else
#define GFP_THISNODE ((__force gfp_t)0)
#endif
/* Flag - indicates that the buffer will be suitable for DMA. Ignored on some
platforms, used as appropriate on others */
#define GFP_DMA __GFP_DMA
/* 4GB DMA on some platforms */
#define GFP_DMA32 __GFP_DMA32
static inline enum zone_type gfp_zone(gfp_t flags)
{
#ifdef CONFIG_ZONE_DMA
if (flags & __GFP_DMA)
return ZONE_DMA;
#endif
#ifdef CONFIG_ZONE_DMA32
if (flags & __GFP_DMA32)
return ZONE_DMA32;
#endif
if ((flags & (__GFP_HIGHMEM | __GFP_MOVABLE)) ==
(__GFP_HIGHMEM | __GFP_MOVABLE))
return ZONE_MOVABLE;
#ifdef CONFIG_HIGHMEM
if (flags & __GFP_HIGHMEM)
return ZONE_HIGHMEM;
#endif
return ZONE_NORMAL;
}
/*
* There is only one page-allocator function, and two main namespaces to
* it. The alloc_page*() variants return 'struct page *' and as such
* can allocate highmem pages, the *get*page*() variants return
* virtual kernel addresses to the allocated page(s).
*/
/*
* We get the zone list from the current node and the gfp_mask.
* This zone list contains a maximum of MAXNODES*MAX_NR_ZONES zones.
*
* For the normal case of non-DISCONTIGMEM systems the NODE_DATA() gets
* optimized to &contig_page_data at compile-time.
*/
#ifndef HAVE_ARCH_FREE_PAGE
static inline void arch_free_page(struct page *page, int order) { }
#endif
#ifndef HAVE_ARCH_ALLOC_PAGE
static inline void arch_alloc_page(struct page *page, int order) { }
#endif
extern struct page *
FASTCALL(__alloc_pages(gfp_t, unsigned int, struct zonelist *));
static inline struct page *alloc_pages_node(int nid, gfp_t gfp_mask,
unsigned int order)
{
if (unlikely(order >= MAX_ORDER))
return NULL;
/* Unknown node is current node */
if (nid < 0)
nid = numa_node_id();
return __alloc_pages(gfp_mask, order,
NODE_DATA(nid)->node_zonelists + gfp_zone(gfp_mask));
}
#ifdef CONFIG_NUMA
extern struct page *alloc_pages_current(gfp_t gfp_mask, unsigned order);
static inline struct page *
alloc_pages(gfp_t gfp_mask, unsigned int order)
{
if (unlikely(order >= MAX_ORDER))
return NULL;
return alloc_pages_current(gfp_mask, order);
}
extern struct page *alloc_page_vma(gfp_t gfp_mask,
struct vm_area_struct *vma, unsigned long addr);
#else
#define alloc_pages(gfp_mask, order) \
alloc_pages_node(numa_node_id(), gfp_mask, order)
#define alloc_page_vma(gfp_mask, vma, addr) alloc_pages(gfp_mask, 0)
#endif
#define alloc_page(gfp_mask) alloc_pages(gfp_mask, 0)
extern unsigned long FASTCALL(__get_free_pages(gfp_t gfp_mask, unsigned int order));
extern unsigned long FASTCALL(get_zeroed_page(gfp_t gfp_mask));
#define __get_free_page(gfp_mask) \
__get_free_pages((gfp_mask),0)
#define __get_dma_pages(gfp_mask, order) \
__get_free_pages((gfp_mask) | GFP_DMA,(order))
extern void FASTCALL(__free_pages(struct page *page, unsigned int order));
extern void FASTCALL(free_pages(unsigned long addr, unsigned int order));
extern void FASTCALL(free_hot_page(struct page *page));
extern void FASTCALL(free_cold_page(struct page *page));
#define __free_page(page) __free_pages((page), 0)
#define free_page(addr) free_pages((addr),0)
void page_alloc_init(void);
void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp);
#endif /* __LINUX_GFP_H */
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