mirror of https://gitee.com/openkylin/linux.git
[PATCH] reduce MAX_NR_ZONES: use enum to define zones, reformat and comment
Use enum for zones and reformat zones dependent information Add comments explaning the use of zones and add a zones_t type for zone numbers. Line up information that will be #ifdefd by the following patches. [akpm@osdl.org: comment cleanups] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Christoph Lameter
Linus Torvalds
parent
98d2b0ebda
commit
2f1b624868
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@ -470,7 +470,7 @@ void split_page(struct page *page, unsigned int order);
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#define SECTIONS_MASK ((1UL << SECTIONS_WIDTH) - 1)
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#define ZONETABLE_MASK ((1UL << ZONETABLE_SHIFT) - 1)
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static inline unsigned long page_zonenum(struct page *page)
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static inline enum zone_type page_zonenum(struct page *page)
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{
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return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
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}
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@ -499,11 +499,12 @@ static inline unsigned long page_to_section(struct page *page)
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return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
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}
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static inline void set_page_zone(struct page *page, unsigned long zone)
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static inline void set_page_zone(struct page *page, enum zone_type zone)
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{
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page->flags &= ~(ZONES_MASK << ZONES_PGSHIFT);
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page->flags |= (zone & ZONES_MASK) << ZONES_PGSHIFT;
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}
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static inline void set_page_node(struct page *page, unsigned long node)
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{
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page->flags &= ~(NODES_MASK << NODES_PGSHIFT);
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@ -515,7 +516,7 @@ static inline void set_page_section(struct page *page, unsigned long section)
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page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;
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}
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static inline void set_page_links(struct page *page, unsigned long zone,
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static inline void set_page_links(struct page *page, enum zone_type zone,
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unsigned long node, unsigned long pfn)
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{
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set_page_zone(page, zone);
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@ -88,14 +88,53 @@ struct per_cpu_pageset {
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#define zone_pcp(__z, __cpu) (&(__z)->pageset[(__cpu)])
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#endif
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#define ZONE_DMA 0
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#define ZONE_DMA32 1
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#define ZONE_NORMAL 2
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#define ZONE_HIGHMEM 3
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enum zone_type {
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/*
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* ZONE_DMA is used when there are devices that are not able
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* to do DMA to all of addressable memory (ZONE_NORMAL). Then we
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* carve out the portion of memory that is needed for these devices.
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* The range is arch specific.
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*
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* Some examples
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*
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* Architecture Limit
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* ---------------------------
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* parisc, ia64, sparc <4G
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* s390 <2G
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* arm26 <48M
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* arm Various
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* alpha Unlimited or 0-16MB.
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*
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* i386, x86_64 and multiple other arches
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* <16M.
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*/
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ZONE_DMA,
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/*
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* x86_64 needs two ZONE_DMAs because it supports devices that are
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* only able to do DMA to the lower 16M but also 32 bit devices that
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* can only do DMA areas below 4G.
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*/
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ZONE_DMA32,
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/*
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* Normal addressable memory is in ZONE_NORMAL. DMA operations can be
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* performed on pages in ZONE_NORMAL if the DMA devices support
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* transfers to all addressable memory.
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*/
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ZONE_NORMAL,
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/*
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* A memory area that is only addressable by the kernel through
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* mapping portions into its own address space. This is for example
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* used by i386 to allow the kernel to address the memory beyond
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* 900MB. The kernel will set up special mappings (page
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* table entries on i386) for each page that the kernel needs to
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* access.
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*/
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ZONE_HIGHMEM,
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#define MAX_NR_ZONES 4 /* Sync this with ZONES_SHIFT */
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#define ZONES_SHIFT 2 /* ceil(log2(MAX_NR_ZONES)) */
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MAX_NR_ZONES
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};
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#define ZONES_SHIFT 2 /* ceil(log2(MAX_NR_ZONES)) */
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/*
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* When a memory allocation must conform to specific limitations (such
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@ -126,16 +165,6 @@ struct per_cpu_pageset {
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/* #define GFP_ZONETYPES (GFP_ZONEMASK + 1) */ /* Non-loner */
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#define GFP_ZONETYPES ((GFP_ZONEMASK + 1) / 2 + 1) /* Loner */
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/*
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* On machines where it is needed (eg PCs) we divide physical memory
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* into multiple physical zones. On a 32bit PC we have 4 zones:
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*
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* ZONE_DMA < 16 MB ISA DMA capable memory
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* ZONE_DMA32 0 MB Empty
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* ZONE_NORMAL 16-896 MB direct mapped by the kernel
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* ZONE_HIGHMEM > 896 MB only page cache and user processes
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*/
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struct zone {
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/* Fields commonly accessed by the page allocator */
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unsigned long free_pages;
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@ -266,7 +295,6 @@ struct zone {
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char *name;
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} ____cacheline_internodealigned_in_smp;
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/*
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* The "priority" of VM scanning is how much of the queues we will scan in one
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* go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the
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@ -373,12 +401,12 @@ static inline int populated_zone(struct zone *zone)
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return (!!zone->present_pages);
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}
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static inline int is_highmem_idx(int idx)
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static inline int is_highmem_idx(enum zone_type idx)
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{
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return (idx == ZONE_HIGHMEM);
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}
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static inline int is_normal_idx(int idx)
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static inline int is_normal_idx(enum zone_type idx)
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{
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return (idx == ZONE_NORMAL);
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}
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@ -68,7 +68,11 @@ static void __free_pages_ok(struct page *page, unsigned int order);
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* TBD: should special case ZONE_DMA32 machines here - in those we normally
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* don't need any ZONE_NORMAL reservation
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*/
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int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = { 256, 256, 32 };
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int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
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256,
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256,
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32
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};
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EXPORT_SYMBOL(totalram_pages);
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@ -79,7 +83,13 @@ EXPORT_SYMBOL(totalram_pages);
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struct zone *zone_table[1 << ZONETABLE_SHIFT] __read_mostly;
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EXPORT_SYMBOL(zone_table);
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static char *zone_names[MAX_NR_ZONES] = { "DMA", "DMA32", "Normal", "HighMem" };
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static char *zone_names[MAX_NR_ZONES] = {
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"DMA",
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"DMA32",
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"Normal",
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"HighMem"
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};
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int min_free_kbytes = 1024;
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unsigned long __meminitdata nr_kernel_pages;
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@ -1487,7 +1497,9 @@ static void __meminit build_zonelists(pg_data_t *pgdat)
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static void __meminit build_zonelists(pg_data_t *pgdat)
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{
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int i, j, k, node, local_node;
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int i, node, local_node;
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enum zone_type k;
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enum zone_type j;
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local_node = pgdat->node_id;
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for (i = 0; i < GFP_ZONETYPES; i++) {
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@ -1675,8 +1687,8 @@ void zone_init_free_lists(struct pglist_data *pgdat, struct zone *zone,
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}
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#define ZONETABLE_INDEX(x, zone_nr) ((x << ZONES_SHIFT) | zone_nr)
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void zonetable_add(struct zone *zone, int nid, int zid, unsigned long pfn,
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unsigned long size)
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void zonetable_add(struct zone *zone, int nid, enum zone_type zid,
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unsigned long pfn, unsigned long size)
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{
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unsigned long snum = pfn_to_section_nr(pfn);
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unsigned long end = pfn_to_section_nr(pfn + size);
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@ -1960,7 +1972,7 @@ __meminit int init_currently_empty_zone(struct zone *zone,
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static void __meminit free_area_init_core(struct pglist_data *pgdat,
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unsigned long *zones_size, unsigned long *zholes_size)
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{
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unsigned long j;
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enum zone_type j;
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int nid = pgdat->node_id;
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unsigned long zone_start_pfn = pgdat->node_start_pfn;
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int ret;
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