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Subject[PATCH 1/5] mm: Make free_area->nr_free per migratetype
Date
This is prep work for introducing a struct page_free_list, which will
have a list head and nr_free - it turns out a fair amount of the code
looking at free_area->nr_free actually wants the number of elements on a
particular freelist.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
---
include/linux/mmzone.h | 14 ++++++++++++--
mm/page_alloc.c | 30 +++++++++++++++++-------------
mm/page_reporting.c | 2 +-
mm/vmstat.c | 28 +++-------------------------
4 files changed, 33 insertions(+), 41 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 6a1d79d846..089587b918 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -96,7 +96,7 @@ extern int page_group_by_mobility_disabled;

struct free_area {
struct list_head free_list[MIGRATE_TYPES];
- unsigned long nr_free;
+ unsigned long nr_free[MIGRATE_TYPES];
};

static inline struct page *get_page_from_free_area(struct free_area *area,
@@ -108,7 +108,17 @@ static inline struct page *get_page_from_free_area(struct free_area *area,

static inline bool free_area_empty(struct free_area *area, int migratetype)
{
- return list_empty(&area->free_list[migratetype]);
+ return area->nr_free[migratetype] == 0;
+}
+
+static inline size_t free_area_nr_free(struct free_area *area)
+{
+ unsigned migratetype;
+ size_t nr_free = 0;
+
+ for (migratetype = 0; migratetype < MIGRATE_TYPES; migratetype++)
+ nr_free += area->nr_free[migratetype];
+ return nr_free;
}

struct pglist_data;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b37435c274..8918c00a91 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -966,7 +966,7 @@ static inline void add_to_free_list(struct page *page, struct zone *zone,
struct free_area *area = &zone->free_area[order];

list_add(&page->lru, &area->free_list[migratetype]);
- area->nr_free++;
+ area->nr_free[migratetype]++;
}

/* Used for pages not on another list */
@@ -976,7 +976,7 @@ static inline void add_to_free_list_tail(struct page *page, struct zone *zone,
struct free_area *area = &zone->free_area[order];

list_add_tail(&page->lru, &area->free_list[migratetype]);
- area->nr_free++;
+ area->nr_free[migratetype]++;
}

/*
@@ -993,7 +993,7 @@ static inline void move_to_free_list(struct page *page, struct zone *zone,
}

static inline void del_page_from_free_list(struct page *page, struct zone *zone,
- unsigned int order)
+ unsigned int order, int migratetype)
{
/* clear reported state and update reported page count */
if (page_reported(page))
@@ -1002,7 +1002,7 @@ static inline void del_page_from_free_list(struct page *page, struct zone *zone,
list_del(&page->lru);
__ClearPageBuddy(page);
set_page_private(page, 0);
- zone->free_area[order].nr_free--;
+ zone->free_area[order].nr_free[migratetype]--;
}

/*
@@ -1098,7 +1098,7 @@ static inline void __free_one_page(struct page *page,
if (page_is_guard(buddy))
clear_page_guard(zone, buddy, order, migratetype);
else
- del_page_from_free_list(buddy, zone, order);
+ del_page_from_free_list(buddy, zone, order, migratetype);
combined_pfn = buddy_pfn & pfn;
page = page + (combined_pfn - pfn);
pfn = combined_pfn;
@@ -2456,7 +2456,7 @@ struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
page = get_page_from_free_area(area, migratetype);
if (!page)
continue;
- del_page_from_free_list(page, zone, current_order);
+ del_page_from_free_list(page, zone, current_order, migratetype);
expand(zone, page, order, current_order, migratetype);
set_pcppage_migratetype(page, migratetype);
return page;
@@ -3525,7 +3525,7 @@ int __isolate_free_page(struct page *page, unsigned int order)

/* Remove page from free list */

- del_page_from_free_list(page, zone, order);
+ del_page_from_free_list(page, zone, order, mt);

/*
* Set the pageblock if the isolated page is at least half of a
@@ -6038,14 +6038,16 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
struct free_area *area = &zone->free_area[order];
int type;

- nr[order] = area->nr_free;
- total += nr[order] << order;
+ nr[order] = 0;
+ types[order] = 0;

- types[order] = 0;
for (type = 0; type < MIGRATE_TYPES; type++) {
if (!free_area_empty(area, type))
types[order] |= 1 << type;
+ nr[order] += area->nr_free[type];
}
+
+ total += nr[order] << order;
}
spin_unlock_irqrestore(&zone->lock, flags);
for (order = 0; order < MAX_ORDER; order++) {
@@ -6623,7 +6625,7 @@ static void __meminit zone_init_free_lists(struct zone *zone)
unsigned int order, t;
for_each_migratetype_order(order, t) {
INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
- zone->free_area[order].nr_free = 0;
+ zone->free_area[order].nr_free[t] = 0;
}
}

@@ -9317,6 +9319,7 @@ void __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
struct page *page;
struct zone *zone;
unsigned int order;
+ unsigned int migratetype;
unsigned long flags;

offline_mem_sections(pfn, end_pfn);
@@ -9346,7 +9349,8 @@ void __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
BUG_ON(page_count(page));
BUG_ON(!PageBuddy(page));
order = buddy_order(page);
- del_page_from_free_list(page, zone, order);
+ migratetype = get_pfnblock_migratetype(page, pfn);
+ del_page_from_free_list(page, zone, order, migratetype);
pfn += (1 << order);
}
spin_unlock_irqrestore(&zone->lock, flags);
@@ -9428,7 +9432,7 @@ bool take_page_off_buddy(struct page *page)
int migratetype = get_pfnblock_migratetype(page_head,
pfn_head);

- del_page_from_free_list(page_head, zone, page_order);
+ del_page_from_free_list(page_head, zone, page_order, migratetype);
break_down_buddy_pages(zone, page_head, page, 0,
page_order, migratetype);
if (!is_migrate_isolate(migratetype))
diff --git a/mm/page_reporting.c b/mm/page_reporting.c
index 382958eef8..4e45ae95db 100644
--- a/mm/page_reporting.c
+++ b/mm/page_reporting.c
@@ -145,7 +145,7 @@ page_reporting_cycle(struct page_reporting_dev_info *prdev, struct zone *zone,
* The division here should be cheap since PAGE_REPORTING_CAPACITY
* should always be a power of 2.
*/
- budget = DIV_ROUND_UP(area->nr_free, PAGE_REPORTING_CAPACITY * 16);
+ budget = DIV_ROUND_UP(area->nr_free[mt], PAGE_REPORTING_CAPACITY * 16);

/* loop through free list adding unreported pages to sg list */
list_for_each_entry_safe(page, next, list, lru) {
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 8ce2620344..eb46f99c72 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1071,7 +1071,7 @@ static void fill_contig_page_info(struct zone *zone,
unsigned long blocks;

/* Count number of free blocks */
- blocks = zone->free_area[order].nr_free;
+ blocks = free_area_nr_free(&zone->free_area[order]);
info->free_blocks_total += blocks;

/* Count free base pages */
@@ -1445,7 +1445,7 @@ static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,

seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
for (order = 0; order < MAX_ORDER; ++order)
- seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
+ seq_printf(m, "%6zu ", free_area_nr_free(&zone->free_area[order]));
seq_putc(m, '\n');
}

@@ -1470,29 +1470,7 @@ static void pagetypeinfo_showfree_print(struct seq_file *m,
zone->name,
migratetype_names[mtype]);
for (order = 0; order < MAX_ORDER; ++order) {
- unsigned long freecount = 0;
- struct free_area *area;
- struct list_head *curr;
- bool overflow = false;
-
- area = &(zone->free_area[order]);
-
- list_for_each(curr, &area->free_list[mtype]) {
- /*
- * Cap the free_list iteration because it might
- * be really large and we are under a spinlock
- * so a long time spent here could trigger a
- * hard lockup detector. Anyway this is a
- * debugging tool so knowing there is a handful
- * of pages of this order should be more than
- * sufficient.
- */
- if (++freecount >= 100000) {
- overflow = true;
- break;
- }
- }
- seq_printf(m, "%s%6lu ", overflow ? ">" : "", freecount);
+ seq_printf(m, "%6zu ", zone->free_area[order].nr_free[mtype]);
spin_unlock_irq(&zone->lock);
cond_resched();
spin_lock_irq(&zone->lock);
--
2.33.0
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