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Page allocator: get rid of the list of cold pages 

We have repeatedly discussed if the cold pages still have a point. There is
one way to join the two lists: Use a single list and put the cold pages at the
end and the hot pages at the beginning. That way a single list can serve for
both types of allocations.

The discussion of the RFC for this and Mel's measurements indicate that
there may not be too much of a point left to having separate lists for
hot and cold pages (see http://marc.info/?t=119492914200001&r=1&w=2).

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Martin Bligh <mbligh@mbligh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Christoph Lameter 2008-02-04 22:29:19 -08:00 committed by Linus Torvalds
parent 5dc3318528
commit 3dfa5721f1
3 changed files with 39 additions and 48 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/mmzone.h
View File

@ -113,7 +113,7 @@ struct per_cpu_pages {
};
struct per_cpu_pageset {
struct per_cpu_pages pcp[2]; /* 0: hot. 1: cold */
struct per_cpu_pages pcp;
#ifdef CONFIG_NUMA
s8 expire;
#endif

55
mm/page_alloc.c
View File

@ -901,24 +901,21 @@ static void drain_pages(unsigned int cpu)
{
unsigned long flags;
struct zone *zone;
int i;
for_each_zone(zone) {
struct per_cpu_pageset *pset;
struct per_cpu_pages *pcp;
if (!populated_zone(zone))
continue;
pset = zone_pcp(zone, cpu);
for (i = 0; i < ARRAY_SIZE(pset->pcp); i++) {
struct per_cpu_pages *pcp;
pcp = &pset->pcp[i];
local_irq_save(flags);
free_pages_bulk(zone, pcp->count, &pcp->list, 0);
pcp->count = 0;
local_irq_restore(flags);
}
pcp = &pset->pcp;
local_irq_save(flags);
free_pages_bulk(zone, pcp->count, &pcp->list, 0);
pcp->count = 0;
local_irq_restore(flags);
}
}
@ -993,10 +990,13 @@ static void fastcall free_hot_cold_page(struct page *page, int cold)
arch_free_page(page, 0);
kernel_map_pages(page, 1, 0);
pcp = &zone_pcp(zone, get_cpu())->pcp[cold];
pcp = &zone_pcp(zone, get_cpu())->pcp;
local_irq_save(flags);
__count_vm_event(PGFREE);
list_add(&page->lru, &pcp->list);
if (cold)
list_add_tail(&page->lru, &pcp->list);
else
list_add(&page->lru, &pcp->list);
set_page_private(page, get_pageblock_migratetype(page));
pcp->count++;
if (pcp->count >= pcp->high) {
@ -1054,7 +1054,7 @@ again:
if (likely(order == 0)) {
struct per_cpu_pages *pcp;
pcp = &zone_pcp(zone, cpu)->pcp[cold];
pcp = &zone_pcp(zone, cpu)->pcp;
local_irq_save(flags);
if (!pcp->count) {
pcp->count = rmqueue_bulk(zone, 0,
@ -1064,9 +1064,15 @@ again:
}
/* Find a page of the appropriate migrate type */
list_for_each_entry(page, &pcp->list, lru)
if (page_private(page) == migratetype)
break;
if (cold) {
list_for_each_entry_reverse(page, &pcp->list, lru)
if (page_private(page) == migratetype)
break;
} else {
list_for_each_entry(page, &pcp->list, lru)
if (page_private(page) == migratetype)
break;
}
/* Allocate more to the pcp list if necessary */
if (unlikely(&page->lru == &pcp->list)) {
@ -1793,12 +1799,9 @@ void show_free_areas(void)
pageset = zone_pcp(zone, cpu);
printk("CPU %4d: Hot: hi:%5d, btch:%4d usd:%4d "
"Cold: hi:%5d, btch:%4d usd:%4d\n",
cpu, pageset->pcp[0].high,
pageset->pcp[0].batch, pageset->pcp[0].count,
pageset->pcp[1].high, pageset->pcp[1].batch,
pageset->pcp[1].count);
printk("CPU %4d: hi:%5d, btch:%4d usd:%4d\n",
cpu, pageset->pcp.high,
pageset->pcp.batch, pageset->pcp.count);
}
}
@ -2596,17 +2599,11 @@ inline void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
memset(p, 0, sizeof(*p));
pcp = &p->pcp[0]; /* hot */
pcp = &p->pcp;
pcp->count = 0;
pcp->high = 6 * batch;
pcp->batch = max(1UL, 1 * batch);
INIT_LIST_HEAD(&pcp->list);
pcp = &p->pcp[1]; /* cold*/
pcp->count = 0;
pcp->high = 2 * batch;
pcp->batch = max(1UL, batch/2);
INIT_LIST_HEAD(&pcp->list);
}
/*
@ -2619,7 +2616,7 @@ static void setup_pagelist_highmark(struct per_cpu_pageset *p,
{
struct per_cpu_pages *pcp;
pcp = &p->pcp[0]; /* hot list */
pcp = &p->pcp;
pcp->high = high;
pcp->batch = max(1UL, high/4);
if ((high/4) > (PAGE_SHIFT * 8))

30
mm/vmstat.c
View File

@ -337,7 +337,7 @@ void refresh_cpu_vm_stats(int cpu)
* Check if there are pages remaining in this pageset
* if not then there is nothing to expire.
*/
if (!p->expire || (!p->pcp[0].count && !p->pcp[1].count))
if (!p->expire || !p->pcp.count)
continue;
/*
@ -352,11 +352,8 @@ void refresh_cpu_vm_stats(int cpu)
if (p->expire)
continue;
if (p->pcp[0].count)
drain_zone_pages(zone, p->pcp + 0);
if (p->pcp[1].count)
drain_zone_pages(zone, p->pcp + 1);
if (p->pcp.count)
drain_zone_pages(zone, &p->pcp);
#endif
}
@ -693,20 +690,17 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
"\n pagesets");
for_each_online_cpu(i) {
struct per_cpu_pageset *pageset;
int j;
pageset = zone_pcp(zone, i);
for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) {
seq_printf(m,
"\n cpu: %i pcp: %i"
"\n count: %i"
"\n high: %i"
"\n batch: %i",
i, j,
pageset->pcp[j].count,
pageset->pcp[j].high,
pageset->pcp[j].batch);
}
seq_printf(m,
"\n cpu: %i"
"\n count: %i"
"\n high: %i"
"\n batch: %i",
i,
pageset->pcp.count,
pageset->pcp.high,
pageset->pcp.batch);
#ifdef CONFIG_SMP
seq_printf(m, "\n vm stats threshold: %d",
pageset->stat_threshold);