The freelists for each allocation type can slowly become corrupted due to
the per-cpu list. Consider what happens when the following happens
1. A 2^(MAX_ORDER-1) list is reserved for __GFP_EASYRCLM pages
2. An order-0 page is allocated from the newly reserved block
3. The page is freed and placed on the per-cpu list
4. alloc_page() is called with GFP_KERNEL as the gfp_mask
5. The per-cpu list is used to satisfy the allocation
This results in a kernel page is in the middle of a RCLM_EASY region. This
means that over long periods of the time, the anti-fragmentation scheme
slowly degrades to the standard allocator.
This patch divides the per-cpu lists into RCLM_TYPES number of lists.
Signed-off-by: Mel Gorman <[email protected]>
Signed-off-by: Joel Schopp <[email protected]>
diff -rup -X /usr/src/patchset-0.5/bin//dontdiff linux-2.6.16-rc1-mm1-002_fragcore/include/linux/mmzone.h linux-2.6.16-rc1-mm1-003_percpu/include/linux/mmzone.h
--- linux-2.6.16-rc1-mm1-002_fragcore/include/linux/mmzone.h 2006-01-19 21:51:05.000000000 +0000
+++ linux-2.6.16-rc1-mm1-003_percpu/include/linux/mmzone.h 2006-01-19 22:15:16.000000000 +0000
@@ -26,6 +26,8 @@
#define RCLM_EASY 1
#define RCLM_TYPES 2
+#define for_each_rclmtype(type) \
+ for (type = 0; type < RCLM_TYPES; type++)
#define for_each_rclmtype_order(type, order) \
for (order = 0; order < MAX_ORDER; order++) \
for (type = 0; type < RCLM_TYPES; type++)
@@ -53,10 +55,10 @@ struct zone_padding {
#endif
struct per_cpu_pages {
- int count; /* number of pages in the list */
+ int count[RCLM_TYPES]; /* number of pages in the list */
int high; /* high watermark, emptying needed */
int batch; /* chunk size for buddy add/remove */
- struct list_head list; /* the list of pages */
+ struct list_head list[RCLM_TYPES]; /* the list of pages */
};
struct per_cpu_pageset {
@@ -71,6 +73,11 @@ struct per_cpu_pageset {
#endif
} ____cacheline_aligned_in_smp;
+static inline int pcp_count(struct per_cpu_pages *pcp)
+{
+ return pcp->count[RCLM_NORCLM] + pcp->count[RCLM_EASY];
+}
+
#ifdef CONFIG_NUMA
#define zone_pcp(__z, __cpu) ((__z)->pageset[(__cpu)])
#else
diff -rup -X /usr/src/patchset-0.5/bin//dontdiff linux-2.6.16-rc1-mm1-002_fragcore/mm/page_alloc.c linux-2.6.16-rc1-mm1-003_percpu/mm/page_alloc.c
--- linux-2.6.16-rc1-mm1-002_fragcore/mm/page_alloc.c 2006-01-19 22:12:09.000000000 +0000
+++ linux-2.6.16-rc1-mm1-003_percpu/mm/page_alloc.c 2006-01-19 22:26:45.000000000 +0000
@@ -663,7 +663,7 @@ static int rmqueue_bulk(struct zone *zon
void drain_remote_pages(void)
{
struct zone *zone;
- int i;
+ int i, pindex;
unsigned long flags;
local_irq_save(flags);
@@ -679,8 +679,12 @@ void drain_remote_pages(void)
struct per_cpu_pages *pcp;
pcp = &pset->pcp[i];
- free_pages_bulk(zone, pcp->count, &pcp->list, 0);
- pcp->count = 0;
+ for_each_rclmtype(pindex) {
+ free_pages_bulk(zone,
+ pcp->count[pindex],
+ &pcp->list[pindex], 0);
+ pcp->count[pindex] = 0;
+ }
}
}
local_irq_restore(flags);
@@ -692,7 +696,7 @@ static void __drain_pages(unsigned int c
{
unsigned long flags;
struct zone *zone;
- int i;
+ int i, pindex;
for_each_zone(zone) {
struct per_cpu_pageset *pset;
@@ -703,8 +707,13 @@ static void __drain_pages(unsigned int c
pcp = &pset->pcp[i];
local_irq_save(flags);
- free_pages_bulk(zone, pcp->count, &pcp->list, 0);
- pcp->count = 0;
+ for_each_rclmtype(pindex) {
+ free_pages_bulk(zone,
+ pcp->count[pindex],
+ &pcp->list[pindex], 0);
+
+ pcp->count[pindex] = 0;
+ }
local_irq_restore(flags);
}
}
@@ -780,6 +789,7 @@ static void zone_statistics(struct zonel
static void fastcall free_hot_cold_page(struct page *page, int cold)
{
struct zone *zone = page_zone(page);
+ int pindex = get_pageblock_type(page);
struct per_cpu_pages *pcp;
unsigned long flags;
@@ -795,11 +805,11 @@ static void fastcall free_hot_cold_page(
pcp = &zone_pcp(zone, get_cpu())->pcp[cold];
local_irq_save(flags);
__inc_page_state(pgfree);
- list_add(&page->lru, &pcp->list);
- pcp->count++;
- if (pcp->count >= pcp->high) {
- free_pages_bulk(zone, pcp->batch, &pcp->list, 0);
- pcp->count -= pcp->batch;
+ list_add(&page->lru, &pcp->list[pindex]);
+ pcp->count[pindex]++;
+ if (pcp->count[pindex] >= pcp->high) {
+ free_pages_bulk(zone, pcp->batch, &pcp->list[pindex], 0);
+ pcp->count[pindex] -= pcp->batch;
}
local_irq_restore(flags);
put_cpu();
@@ -845,16 +855,17 @@ again:
pcp = &zone_pcp(zone, cpu)->pcp[cold];
local_irq_save(flags);
- if (!pcp->count) {
- pcp->count += rmqueue_bulk(zone, 0,
- pcp->batch, &pcp->list,
+ if (!pcp->count[alloctype]) {
+ pcp->count[alloctype] += rmqueue_bulk(zone, 0,
+ pcp->batch,
+ &pcp->list[alloctype],
alloctype);
if (unlikely(!pcp->count))
goto failed;
}
- page = list_entry(pcp->list.next, struct page, lru);
+ page = list_entry(pcp->list[alloctype].next, struct page, lru);
list_del(&page->lru);
- pcp->count--;
+ pcp->count[alloctype]--;
} else {
spin_lock_irqsave(&zone->lock, flags);
page = __rmqueue(zone, order, alloctype);
@@ -1534,7 +1545,7 @@ void show_free_areas(void)
temperature ? "cold" : "hot",
pageset->pcp[temperature].high,
pageset->pcp[temperature].batch,
- pageset->pcp[temperature].count);
+ pcp_count(&pageset->pcp[temperature]));
}
}
@@ -1978,16 +1989,20 @@ inline void setup_pageset(struct per_cpu
memset(p, 0, sizeof(*p));
pcp = &p->pcp[0]; /* hot */
- pcp->count = 0;
+ pcp->count[RCLM_NORCLM] = 0;
+ pcp->count[RCLM_EASY] = 0;
pcp->high = 6 * batch;
pcp->batch = max(1UL, 1 * batch);
- INIT_LIST_HEAD(&pcp->list);
+ INIT_LIST_HEAD(&pcp->list[RCLM_NORCLM]);
+ INIT_LIST_HEAD(&pcp->list[RCLM_EASY]);
pcp = &p->pcp[1]; /* cold*/
- pcp->count = 0;
+ pcp->count[RCLM_NORCLM] = 0;
+ pcp->count[RCLM_EASY] = 0;
pcp->high = 2 * batch;
pcp->batch = max(1UL, batch/2);
- INIT_LIST_HEAD(&pcp->list);
+ INIT_LIST_HEAD(&pcp->list[RCLM_NORCLM]);
+ INIT_LIST_HEAD(&pcp->list[RCLM_EASY]);
}
/*
@@ -2403,7 +2418,7 @@ static int zoneinfo_show(struct seq_file
"\n high: %i"
"\n batch: %i",
i, j,
- pageset->pcp[j].count,
+ pcp_count(&pageset->pcp[j]),
pageset->pcp[j].high,
pageset->pcp[j].batch);
}
-
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