[PATCH] zoned vm counters: conversion of nr_pagecache to 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
named NR_FILE_PAGES.

Updates of the page cache counters are always performed with interrupts off.
We can therefore use the __ variant here.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

6 files changed, 7 insertions, 17 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 648f2c0..87d62c4 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -120,7 +120,7 @@ void __remove_from_page_cache(struct page *page)
 	radix_tree_delete(&mapping->page_tree, page->index);
 	page->mapping = NULL;
 	mapping->nrpages--;
-	pagecache_acct(-1);
+	__dec_zone_page_state(page, NR_FILE_PAGES);
 }
 
 void remove_from_page_cache(struct page *page)
@@ -449,7 +449,7 @@ int add_to_page_cache(struct page *page, struct address_space *mapping,
 			page->mapping = mapping;
 			page->index = offset;
 			mapping->nrpages++;
-			pagecache_acct(1);
+			__inc_zone_page_state(page, NR_FILE_PAGES);
 		}
 		write_unlock_irq(&mapping->tree_lock);
 		radix_tree_preload_end();
diff --git a/mm/mmap.c b/mm/mmap.c
index 6446c61..c1868ec 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -96,7 +96,7 @@ int __vm_enough_memory(long pages, int cap_sys_admin)
 	if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
 		unsigned long n;
 
-		free = get_page_cache_size();
+		free = global_page_state(NR_FILE_PAGES);
 		free += nr_swap_pages;
 
 		/*
diff --git a/mm/nommu.c b/mm/nommu.c
index 029fada..5151c44 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1122,7 +1122,7 @@ int __vm_enough_memory(long pages, int cap_sys_admin)
 	if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
 		unsigned long n;
 
-		free = get_page_cache_size();
+		free = global_page_state(NR_FILE_PAGES);
 		free += nr_swap_pages;
 
 		/*
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 04dd2b0..8350720 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2124,16 +2124,11 @@ static int page_alloc_cpu_notify(struct notifier_block *self,
 				 unsigned long action, void *hcpu)
 {
 	int cpu = (unsigned long)hcpu;
-	long *count;
 	unsigned long *src, *dest;
 
 	if (action == CPU_DEAD) {
 		int i;
 
-		/* Drain local pagecache count. */
-		count = &per_cpu(nr_pagecache_local, cpu);
-		atomic_add(*count, &nr_pagecache);
-		*count = 0;
 		local_irq_disable();
 		__drain_pages(cpu);
 
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 7535211..fccbd9b 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -87,7 +87,7 @@ static int __add_to_swap_cache(struct page *page, swp_entry_t entry,
 			SetPageSwapCache(page);
 			set_page_private(page, entry.val);
 			total_swapcache_pages++;
-			pagecache_acct(1);
+			__inc_zone_page_state(page, NR_FILE_PAGES);
 		}
 		write_unlock_irq(&swapper_space.tree_lock);
 		radix_tree_preload_end();
@@ -132,7 +132,7 @@ void __delete_from_swap_cache(struct page *page)
 	set_page_private(page, 0);
 	ClearPageSwapCache(page);
 	total_swapcache_pages--;
-	pagecache_acct(-1);
+	__dec_zone_page_state(page, NR_FILE_PAGES);
 	INC_CACHE_INFO(del_total);
 }
 
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 4800091..f16b33e 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -20,12 +20,6 @@
  */
 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;
@@ -402,6 +396,7 @@ struct seq_operations fragmentation_op = {
 static char *vmstat_text[] = {
 	/* Zoned VM counters */
 	"nr_mapped",
+	"nr_file_pages",
 
 	/* Page state */
 	"nr_dirty",