[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>

2 files changed, 1 insertions, 46 deletions

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index eb42c12..08be91e 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -49,7 +49,7 @@ struct zone_padding {
 enum zone_stat_item {
 	NR_FILE_MAPPED,	/* mapped into pagetables.
 			   only modified from process context */
-
+	NR_FILE_PAGES,
 	NR_VM_ZONE_STAT_ITEMS };
 
 struct per_cpu_pages {
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 1245df7..0a2f5d2 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -113,51 +113,6 @@ int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
 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.
  */