From: Christoph Lameter Conversion of nr_pagecache to a per zone counter Currently a single atomic variable is used to establish the size of the page cache in the whole machine. The zoned VM counters have the same method of implementation as the nr_pagecache code but also allow the determination of the pagecache size per zone. Remove the special implementation for nr_pagecache and make it a zoned counter. Updates of the page cache counters are always performed with interrupts off. We can therefore use the __ variant here. This will make UP no longer require atomic operations for nr_pagecache. Signed-off-by: Christoph Lameter Signed-off-by: Andrew Morton --- arch/sparc/kernel/sys_sunos.c | 2 - arch/sparc64/kernel/sys_sunos32.c | 2 - fs/proc/proc_misc.c | 2 - include/linux/mmzone.h | 2 - include/linux/pagemap.h | 45 ---------------------------- mm/filemap.c | 4 +- mm/mmap.c | 2 - mm/nommu.c | 2 - mm/page_alloc.c | 7 ---- mm/swap_state.c | 4 +- 10 files changed, 11 insertions(+), 61 deletions(-) diff -puN arch/sparc64/kernel/sys_sunos32.c~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter arch/sparc64/kernel/sys_sunos32.c --- devel/arch/sparc64/kernel/sys_sunos32.c~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter 2006-06-09 15:17:44.000000000 -0700 +++ devel-akpm/arch/sparc64/kernel/sys_sunos32.c 2006-06-09 15:17:44.000000000 -0700 @@ -155,7 +155,7 @@ asmlinkage int sunos_brk(u32 baddr) * simple, it hopefully works in most obvious cases.. Easy to * fool it, but this should catch most mistakes. */ - freepages = get_page_cache_size(); + freepages = global_page_state(NR_PAGECACHE); freepages >>= 1; freepages += nr_free_pages(); freepages += nr_swap_pages; diff -puN arch/sparc/kernel/sys_sunos.c~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter arch/sparc/kernel/sys_sunos.c --- devel/arch/sparc/kernel/sys_sunos.c~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter 2006-06-09 15:17:44.000000000 -0700 +++ devel-akpm/arch/sparc/kernel/sys_sunos.c 2006-06-09 15:17:44.000000000 -0700 @@ -196,7 +196,7 @@ asmlinkage int sunos_brk(unsigned long b * simple, it hopefully works in most obvious cases.. Easy to * fool it, but this should catch most mistakes. */ - freepages = get_page_cache_size(); + freepages = global_page_state(NR_PAGECACHE); freepages >>= 1; freepages += nr_free_pages(); freepages += nr_swap_pages; diff -puN fs/proc/proc_misc.c~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter fs/proc/proc_misc.c --- devel/fs/proc/proc_misc.c~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter 2006-06-09 15:17:44.000000000 -0700 +++ devel-akpm/fs/proc/proc_misc.c 2006-06-09 15:17:44.000000000 -0700 @@ -142,7 +142,7 @@ static int meminfo_read_proc(char *page, allowed = ((totalram_pages - hugetlb_total_pages()) * sysctl_overcommit_ratio / 100) + total_swap_pages; - cached = get_page_cache_size() - total_swapcache_pages - i.bufferram; + cached = global_page_state(NR_PAGECACHE) - total_swapcache_pages - i.bufferram; if (cached < 0) cached = 0; diff -puN include/linux/mmzone.h~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter include/linux/mmzone.h --- devel/include/linux/mmzone.h~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter 2006-06-09 15:17:44.000000000 -0700 +++ devel-akpm/include/linux/mmzone.h 2006-06-09 15:17:44.000000000 -0700 @@ -49,7 +49,7 @@ struct zone_padding { enum zone_stat_item { NR_MAPPED, /* mapped into pagetables. only modified from process context */ - + NR_PAGECACHE, /* file backed pages */ NR_STAT_ITEMS }; struct per_cpu_pages { diff -puN include/linux/pagemap.h~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter include/linux/pagemap.h --- devel/include/linux/pagemap.h~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter 2006-06-09 15:17:44.000000000 -0700 +++ devel-akpm/include/linux/pagemap.h 2006-06-09 15:17:44.000000000 -0700 @@ -106,51 +106,6 @@ int add_to_page_cache_lru(struct page *p extern void remove_from_page_cache(struct page *page); extern void __remove_from_page_cache(struct page *page); -extern atomic_t nr_pagecache; - -#ifdef CONFIG_SMP - -#define PAGECACHE_ACCT_THRESHOLD max(16, NR_CPUS * 2) -DECLARE_PER_CPU(long, nr_pagecache_local); - -/* - * pagecache_acct implements approximate accounting for pagecache. - * vm_enough_memory() do not need high accuracy. Writers will keep - * an offset in their per-cpu arena and will spill that into the - * global count whenever the absolute value of the local count - * exceeds the counter's threshold. - * - * MUST be protected from preemption. - * current protection is mapping->page_lock. - */ -static inline void pagecache_acct(int count) -{ - long *local; - - local = &__get_cpu_var(nr_pagecache_local); - *local += count; - if (*local > PAGECACHE_ACCT_THRESHOLD || *local < -PAGECACHE_ACCT_THRESHOLD) { - atomic_add(*local, &nr_pagecache); - *local = 0; - } -} - -#else - -static inline void pagecache_acct(int count) -{ - atomic_add(count, &nr_pagecache); -} -#endif - -static inline unsigned long get_page_cache_size(void) -{ - int ret = atomic_read(&nr_pagecache); - if (unlikely(ret < 0)) - ret = 0; - return ret; -} - /* * Return byte-offset into filesystem object for page. */ diff -puN mm/filemap.c~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter mm/filemap.c --- devel/mm/filemap.c~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter 2006-06-09 15:17:44.000000000 -0700 +++ devel-akpm/mm/filemap.c 2006-06-09 15:17:44.000000000 -0700 @@ -120,7 +120,7 @@ void __remove_from_page_cache(struct pag radix_tree_delete(&mapping->page_tree, page->index); page->mapping = NULL; mapping->nrpages--; - pagecache_acct(-1); + __dec_zone_page_state(page, NR_PAGECACHE); } void remove_from_page_cache(struct page *page) @@ -415,7 +415,7 @@ int add_to_page_cache(struct page *page, page->mapping = mapping; page->index = offset; mapping->nrpages++; - pagecache_acct(1); + __inc_zone_page_state(page, NR_PAGECACHE); } write_unlock_irq(&mapping->tree_lock); radix_tree_preload_end(); diff -puN mm/mmap.c~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter mm/mmap.c --- devel/mm/mmap.c~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter 2006-06-09 15:17:44.000000000 -0700 +++ devel-akpm/mm/mmap.c 2006-06-09 15:17:44.000000000 -0700 @@ -96,7 +96,7 @@ int __vm_enough_memory(long pages, int c if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { unsigned long n; - free = get_page_cache_size(); + free = global_page_state(NR_PAGECACHE); free += nr_swap_pages; /* diff -puN mm/nommu.c~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter mm/nommu.c --- devel/mm/nommu.c~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter 2006-06-09 15:17:44.000000000 -0700 +++ devel-akpm/mm/nommu.c 2006-06-09 15:17:44.000000000 -0700 @@ -1122,7 +1122,7 @@ int __vm_enough_memory(long pages, int c if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { unsigned long n; - free = get_page_cache_size(); + free = global_page_state(NR_PAGECACHE); free += nr_swap_pages; /* diff -puN mm/page_alloc.c~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter mm/page_alloc.c --- devel/mm/page_alloc.c~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter 2006-06-09 15:17:44.000000000 -0700 +++ devel-akpm/mm/page_alloc.c 2006-06-09 15:17:44.000000000 -0700 @@ -1510,12 +1510,6 @@ static void show_node(struct zone *zone) */ static DEFINE_PER_CPU(struct page_state, page_states) = {0}; -atomic_t nr_pagecache = ATOMIC_INIT(0); -EXPORT_SYMBOL(nr_pagecache); -#ifdef CONFIG_SMP -DEFINE_PER_CPU(long, nr_pagecache_local) = 0; -#endif - static void __get_page_state(struct page_state *ret, int nr, cpumask_t *cpumask) { unsigned cpu; @@ -2710,6 +2704,7 @@ struct seq_operations zoneinfo_op = { static char *vmstat_text[] = { /* Zoned VM counters */ "nr_mapped", + "nr_pagecache", /* Page state */ "nr_dirty", diff -puN mm/swap_state.c~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter mm/swap_state.c --- devel/mm/swap_state.c~zoned-vm-counters-conversion-of-nr_pagecache-to-per-zone-counter 2006-06-09 15:17:44.000000000 -0700 +++ devel-akpm/mm/swap_state.c 2006-06-09 15:17:44.000000000 -0700 @@ -87,7 +87,7 @@ static int __add_to_swap_cache(struct pa SetPageSwapCache(page); set_page_private(page, entry.val); total_swapcache_pages++; - pagecache_acct(1); + __inc_zone_page_state(page, NR_PAGECACHE); } write_unlock_irq(&swapper_space.tree_lock); radix_tree_preload_end(); @@ -132,7 +132,7 @@ void __delete_from_swap_cache(struct pag set_page_private(page, 0); ClearPageSwapCache(page); total_swapcache_pages--; - pagecache_acct(-1); + __dec_zone_page_state(page, NR_PAGECACHE); INC_CACHE_INFO(del_total); } _