[PATCH 05/21] Conversion of nr_pagecache to per zone counter

Christoph Lameter
2006-06-14T01:03:30Z

Subject: zoned vm counters: conversion of nr_pagecache to per zone counter
From: Christoph Lameter <clameter@sgi.com>

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.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>

Index: linux-2.6.17-rc6-cl/arch/sparc64/kernel/sys_sunos32.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/arch/sparc64/kernel/sys_sunos32.c 2006-06-12 12:42:42.240680230 -0700
+++ linux-2.6.17-rc6-cl/arch/sparc64/kernel/sys_sunos32.c 2006-06-13 10:19:38.470745634 -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-cl/arch/sparc/kernel/sys_sunos.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/arch/sparc/kernel/sys_sunos.c 2006-06-12 12:42:42.249468748 -0700
+++ linux-2.6.17-rc6-cl/arch/sparc/kernel/sys_sunos.c 2006-06-13 10:19:38.471722136 -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-cl/fs/proc/proc_misc.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/fs/proc/proc_misc.c 2006-06-13 10:19:37.517679599 -0700
+++ linux-2.6.17-rc6-cl/fs/proc/proc_misc.c 2006-06-13 10:19:38.472698639 -0700
@@ -142,7 +142,8 @@ 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-cl/include/linux/pagemap.h
===================================================================
--- linux-2.6.17-rc6-cl.orig/include/linux/pagemap.h 2006-06-12 12:42:50.853428498 -0700
+++ linux-2.6.17-rc6-cl/include/linux/pagemap.h 2006-06-13 10:19:38.473675141 -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-cl/mm/filemap.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/mm/filemap.c 2006-06-12 12:42:52.024254482 -0700
+++ linux-2.6.17-rc6-cl/mm/filemap.c 2006-06-13 10:19:38.475628145 -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-cl/mm/mmap.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/mm/mmap.c 2006-06-12 12:42:52.037925511 -0700
+++ linux-2.6.17-rc6-cl/mm/mmap.c 2006-06-13 10:19:38.476604647 -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-cl/mm/nommu.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/mm/nommu.c 2006-06-05 17:57:02.000000000 -0700
+++ linux-2.6.17-rc6-cl/mm/nommu.c 2006-06-13 10:19:38.476604647 -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-cl/mm/page_alloc.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/mm/page_alloc.c 2006-06-13 10:19:37.520609105 -0700
+++ linux-2.6.17-rc6-cl/mm/page_alloc.c 2006-06-13 10:19:38.478557651 -0700
@@ -2231,16 +2231,11 @@ static int page_alloc_cpu_notify(struct
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);

Index: linux-2.6.17-rc6-cl/mm/swap_state.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/mm/swap_state.c 2006-06-12 12:42:52.062338063 -0700
+++ linux-2.6.17-rc6-cl/mm/swap_state.c 2006-06-13 10:19:38.479534153 -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-cl/include/linux/mmzone.h
===================================================================
--- linux-2.6.17-rc6-cl.orig/include/linux/mmzone.h 2006-06-13 10:19:37.518656101 -0700
+++ linux-2.6.17-rc6-cl/include/linux/mmzone.h 2006-06-13 10:19:38.479534153 -0700
@@ -49,7 +49,7 @@ struct zone_padding {
enum zone_stat_item {
NR_MAPPED, /* mapped into pagetables.
only modified from process context */
-
+ NR_PAGECACHE,
NR_VM_ZONE_STAT_ITEMS };

struct per_cpu_pages {
Index: linux-2.6.17-rc6-cl/arch/s390/appldata/appldata_mem.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/arch/s390/appldata/appldata_mem.c 2006-06-12 12:42:42.183066607 -0700
+++ linux-2.6.17-rc6-cl/arch/s390/appldata/appldata_mem.c 2006-06-13 10:19:38.480510655 -0700
@@ -130,7 +130,8 @@ static void appldata_get_mem_data(void *
mem_data->totalhigh = P2K(val.totalhigh);
mem_data->freehigh = P2K(val.freehigh);
mem_data->bufferram = P2K(val.bufferram);
- mem_data->cached = P2K(atomic_read(&nr_pagecache) - val.bufferram);
+ mem_data->cached = P2K(global_page_state(NR_PAGECACHE)
+ - val.bufferram);

si_swapinfo(&val);
mem_data->totalswap = P2K(val.totalswap);
Index: linux-2.6.17-rc6-cl/drivers/base/node.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/drivers/base/node.c 2006-06-13 10:19:37.516703097 -0700
+++ linux-2.6.17-rc6-cl/drivers/base/node.c 2006-06-13 10:19:38.481487157 -0700
@@ -69,6 +69,7 @@ static ssize_t node_read_meminfo(struct
"Node %d LowFree: %8lu kB\n"
"Node %d Dirty: %8lu kB\n"
"Node %d Writeback: %8lu kB\n"
+ "Node %d PageCache: %8lu kB\n"
"Node %d Mapped: %8lu kB\n"
"Node %d Slab: %8lu kB\n",
nid, K(i.totalram),
@@ -82,6 +83,7 @@ static ssize_t node_read_meminfo(struct
nid, K(i.freeram - i.freehigh),
nid, K(ps.nr_dirty),
nid, K(ps.nr_writeback),
+ nid, K(node_page_state(nid, NR_PAGECACHE)),
nid, K(node_page_state(nid, NR_MAPPED)),
nid, K(ps.nr_slab));
n += hugetlb_report_node_meminfo(nid, buf + n);
Index: linux-2.6.17-rc6-cl/mm/vmstat.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/mm/vmstat.c 2006-06-13 10:19:37.523538611 -0700
+++ linux-2.6.17-rc6-cl/mm/vmstat.c 2006-06-13 10:44:03.861517159 -0700
@@ -20,12 +20,6 @@
*/
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;
@@ -464,6 +458,7 @@ struct seq_operations fragmentation_op =
static char *vmstat_text[] = {
/* Zoned VM counters */
"nr_mapped",
+ "nr_pagecache",

/* Page state */
"nr_dirty",