[RFC PATCH 5/8] mm: Add data-structures to describe memory regionswithin the zones' freelists

From: Srivatsa S. Bhat
Date: Tue Nov 06 2012 - 14:54:34 EST


In order to influence page allocation decisions (i.e., to make page-allocation
region-aware), we need to be able to distinguish pageblocks belonging to
different zone memory regions within the zones' freelists.

So, within every freelist in a zone, provide pointers to describe the
boundaries of zone memory regions and counters to track the number of free
pageblocks within each region.

Also, fixup the references to the freelist's list_head inside struct free_area.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
---

include/linux/mmzone.h | 17 ++++++++++++++++-
mm/compaction.c | 8 ++++----
mm/page_alloc.c | 21 +++++++++++----------
mm/vmstat.c | 2 +-
4 files changed, 32 insertions(+), 16 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 3982354..aba4d68 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -82,8 +82,23 @@ static inline int get_pageblock_migratetype(struct page *page)

#define MAX_NR_REGIONS 256

+struct mem_region_list {
+ struct list_head *page_block;
+ unsigned long nr_free;
+};
+
+struct free_list {
+ struct list_head list;
+
+ /*
+ * Demarcates pageblocks belonging to different regions within
+ * this freelist.
+ */
+ struct mem_region_list mr_list[MAX_NR_REGIONS];
+};
+
struct free_area {
- struct list_head free_list[MIGRATE_TYPES];
+ struct free_list free_list[MIGRATE_TYPES];
unsigned long nr_free;
};

diff --git a/mm/compaction.c b/mm/compaction.c
index 9eef558..95f5c92 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -247,14 +247,14 @@ static void compact_capture_page(struct compact_control *cc)
struct page *page;
struct free_area *area;
area = &(cc->zone->free_area[order]);
- if (list_empty(&area->free_list[mtype]))
+ if (list_empty(&area->free_list[mtype].list))
continue;

/* Take the lock and attempt capture of the page */
if (!compact_trylock_irqsave(&cc->zone->lock, &flags, cc))
return;
- if (!list_empty(&area->free_list[mtype])) {
- page = list_entry(area->free_list[mtype].next,
+ if (!list_empty(&area->free_list[mtype].list)) {
+ page = list_entry(area->free_list[mtype].list.next,
struct page, lru);
if (capture_free_page(page, cc->order, mtype)) {
spin_unlock_irqrestore(&cc->zone->lock,
@@ -866,7 +866,7 @@ static int compact_finished(struct zone *zone,
for (order = cc->order; order < MAX_ORDER; order++) {
struct free_area *area = &zone->free_area[cc->order];
/* Job done if page is free of the right migratetype */
- if (!list_empty(&area->free_list[cc->migratetype]))
+ if (!list_empty(&area->free_list[cc->migratetype].list))
return COMPACT_PARTIAL;

/* Job done if allocation would set block type */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7fd89cd..62d0a9a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -588,12 +588,13 @@ static inline void __free_one_page(struct page *page,
higher_buddy = higher_page + (buddy_idx - combined_idx);
if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
list_add_tail(&page->lru,
- &zone->free_area[order].free_list[migratetype]);
+ &zone->free_area[order].free_list[migratetype].list);
goto out;
}
}

- list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
+ list_add(&page->lru,
+ &zone->free_area[order].free_list[migratetype].list);
out:
zone->free_area[order].nr_free++;
}
@@ -811,7 +812,7 @@ static inline void expand(struct zone *zone, struct page *page,
continue;
}
#endif
- list_add(&page[size].lru, &area->free_list[migratetype]);
+ list_add(&page[size].lru, &area->free_list[migratetype].list);
area->nr_free++;
set_page_order(&page[size], high);
}
@@ -873,10 +874,10 @@ struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
/* Find a page of the appropriate size in the preferred list */
for (current_order = order; current_order < MAX_ORDER; ++current_order) {
area = &(zone->free_area[current_order]);
- if (list_empty(&area->free_list[migratetype]))
+ if (list_empty(&area->free_list[migratetype].list))
continue;

- page = list_entry(area->free_list[migratetype].next,
+ page = list_entry(area->free_list[migratetype].list.next,
struct page, lru);
list_del(&page->lru);
rmv_page_order(page);
@@ -946,7 +947,7 @@ int move_freepages(struct zone *zone,

order = page_order(page);
list_move(&page->lru,
- &zone->free_area[order].free_list[migratetype]);
+ &zone->free_area[order].free_list[migratetype].list);
set_freepage_migratetype(page, migratetype);
page += 1 << order;
pages_moved += 1 << order;
@@ -1007,10 +1008,10 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
break;

area = &(zone->free_area[current_order]);
- if (list_empty(&area->free_list[migratetype]))
+ if (list_empty(&area->free_list[migratetype].list))
continue;

- page = list_entry(area->free_list[migratetype].next,
+ page = list_entry(area->free_list[migratetype].list.next,
struct page, lru);
area->nr_free--;

@@ -1274,7 +1275,7 @@ void mark_free_pages(struct zone *zone)
}

for_each_migratetype_order(order, t) {
- list_for_each(curr, &zone->free_area[order].free_list[t]) {
+ list_for_each(curr, &zone->free_area[order].free_list[t].list) {
unsigned long i;

pfn = page_to_pfn(list_entry(curr, struct page, lru));
@@ -3859,7 +3860,7 @@ static void __meminit zone_init_free_lists(struct zone *zone)
{
int order, t;
for_each_migratetype_order(order, t) {
- INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
+ INIT_LIST_HEAD(&zone->free_area[order].free_list[t].list);
zone->free_area[order].nr_free = 0;
}
}
diff --git a/mm/vmstat.c b/mm/vmstat.c
index c737057..8183331 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -847,7 +847,7 @@ static void pagetypeinfo_showfree_print(struct seq_file *m,

area = &(zone->free_area[order]);

- list_for_each(curr, &area->free_list[mtype])
+ list_for_each(curr, &area->free_list[mtype].list)
freecount++;
seq_printf(m, "%6lu ", freecount);
}

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