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 Index: linux-2.6.17-rc6-mm1/include/linux/pagemap.h =================================================================== --- linux-2.6.17-rc6-mm1.orig/include/linux/pagemap.h 2006-06-08 13:03:39.304520730 -0700 +++ linux-2.6.17-rc6-mm1/include/linux/pagemap.h 2006-06-08 14:07:35.879548728 -0700 @@ -115,51 +115,6 @@ 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. */ Index: linux-2.6.17-rc6-mm1/mm/swap_state.c =================================================================== --- linux-2.6.17-rc6-mm1.orig/mm/swap_state.c 2006-06-08 13:03:39.924599579 -0700 +++ linux-2.6.17-rc6-mm1/mm/swap_state.c 2006-06-08 14:07:35.880525230 -0700 @@ -89,7 +89,7 @@ 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(); @@ -135,7 +135,7 @@ 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); } Index: linux-2.6.17-rc6-mm1/mm/filemap.c =================================================================== --- linux-2.6.17-rc6-mm1.orig/mm/filemap.c 2006-06-08 13:03:39.864056448 -0700 +++ linux-2.6.17-rc6-mm1/mm/filemap.c 2006-06-08 14:07:35.881501732 -0700 @@ -126,7 +126,7 @@ 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); } EXPORT_SYMBOL(__remove_from_page_cache); @@ -424,7 +424,7 @@ 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(); Index: linux-2.6.17-rc6-mm1/mm/page_alloc.c =================================================================== --- linux-2.6.17-rc6-mm1.orig/mm/page_alloc.c 2006-06-08 13:55:23.119232821 -0700 +++ linux-2.6.17-rc6-mm1/mm/page_alloc.c 2006-06-08 14:07:35.883454737 -0700 @@ -1583,12 +1583,6 @@ 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; @@ -2802,6 +2796,7 @@ struct seq_operations zoneinfo_op = { static char *vmstat_text[] = { /* Zoned VM counters */ "nr_mapped", + "nr_pagecache", /* Page state */ "nr_dirty", Index: linux-2.6.17-rc6-mm1/mm/mmap.c =================================================================== --- linux-2.6.17-rc6-mm1.orig/mm/mmap.c 2006-06-08 13:03:39.900187026 -0700 +++ linux-2.6.17-rc6-mm1/mm/mmap.c 2006-06-08 14:07:35.884431239 -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; /* Index: linux-2.6.17-rc6-mm1/mm/nommu.c =================================================================== --- linux-2.6.17-rc6-mm1.orig/mm/nommu.c 2006-06-05 17:57:02.000000000 -0700 +++ linux-2.6.17-rc6-mm1/mm/nommu.c 2006-06-08 14:07:36.292609102 -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; /* Index: linux-2.6.17-rc6-mm1/arch/sparc64/kernel/sys_sunos32.c =================================================================== --- linux-2.6.17-rc6-mm1.orig/arch/sparc64/kernel/sys_sunos32.c 2006-06-08 13:03:31.354816936 -0700 +++ linux-2.6.17-rc6-mm1/arch/sparc64/kernel/sys_sunos32.c 2006-06-08 14:07:36.469355975 -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; Index: linux-2.6.17-rc6-mm1/arch/sparc/kernel/sys_sunos.c =================================================================== --- linux-2.6.17-rc6-mm1.orig/arch/sparc/kernel/sys_sunos.c 2006-06-08 13:03:31.362628953 -0700 +++ linux-2.6.17-rc6-mm1/arch/sparc/kernel/sys_sunos.c 2006-06-08 14:07:36.481074000 -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; Index: linux-2.6.17-rc6-mm1/fs/proc/proc_misc.c =================================================================== --- linux-2.6.17-rc6-mm1.orig/fs/proc/proc_misc.c 2006-06-08 13:55:23.115326813 -0700 +++ linux-2.6.17-rc6-mm1/fs/proc/proc_misc.c 2006-06-08 14:07:36.482050502 -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; Index: linux-2.6.17-rc6-mm1/include/linux/mmzone.h =================================================================== --- linux-2.6.17-rc6-mm1.orig/include/linux/mmzone.h 2006-06-08 13:55:23.121185825 -0700 +++ linux-2.6.17-rc6-mm1/include/linux/mmzone.h 2006-06-08 14:07:36.482050502 -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 }; #ifdef CONFIG_SMP