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[PATCH] zoned vm counters: conversion of nr_pagecache to per zone counter

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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>
This commit is contained in:
Christoph Lameter
2006-06-30 01:55:35 -07:00
committed by Linus Torvalds
parent 65ba55f500
commit 347ce434d5
13 changed files with 16 additions and 67 deletions
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45
include/linux/pagemap.h
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@@ -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.
*/