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Subject[PATCH 2/5] mm: Introduce struct page_free_list
Date
Small type system cleanup, enabling further cleanups and possibly
switching the freelists from linked lists to radix trees.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
---
include/linux/mmzone.h | 14 +++++++++-----
kernel/crash_core.c | 4 ++--
mm/compaction.c | 20 +++++++++++---------
mm/page_alloc.c | 30 +++++++++++++++---------------
mm/page_reporting.c | 20 ++++++++++----------
mm/vmstat.c | 2 +-
6 files changed, 48 insertions(+), 42 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 089587b918..1fe820ead2 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -94,21 +94,25 @@ extern int page_group_by_mobility_disabled;
#define get_pageblock_migratetype(page) \
get_pfnblock_flags_mask(page, page_to_pfn(page), MIGRATETYPE_MASK)

+struct page_free_list {
+ struct list_head list;
+ size_t nr;
+};
+
struct free_area {
- struct list_head free_list[MIGRATE_TYPES];
- unsigned long nr_free[MIGRATE_TYPES];
+ struct page_free_list free[MIGRATE_TYPES];
};

static inline struct page *get_page_from_free_area(struct free_area *area,
int migratetype)
{
- return list_first_entry_or_null(&area->free_list[migratetype],
+ return list_first_entry_or_null(&area->free[migratetype].list,
struct page, lru);
}

static inline bool free_area_empty(struct free_area *area, int migratetype)
{
- return area->nr_free[migratetype] == 0;
+ return area->free[migratetype].nr == 0;
}

static inline size_t free_area_nr_free(struct free_area *area)
@@ -117,7 +121,7 @@ static inline size_t free_area_nr_free(struct free_area *area)
size_t nr_free = 0;

for (migratetype = 0; migratetype < MIGRATE_TYPES; migratetype++)
- nr_free += area->nr_free[migratetype];
+ nr_free += area->free[migratetype].nr;
return nr_free;
}

diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index eb53f5ec62..f9cc4c3cd1 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -447,14 +447,14 @@ static int __init crash_save_vmcoreinfo_init(void)
VMCOREINFO_OFFSET(zone, free_area);
VMCOREINFO_OFFSET(zone, vm_stat);
VMCOREINFO_OFFSET(zone, spanned_pages);
- VMCOREINFO_OFFSET(free_area, free_list);
+ VMCOREINFO_OFFSET(free_area, free);
VMCOREINFO_OFFSET(list_head, next);
VMCOREINFO_OFFSET(list_head, prev);
VMCOREINFO_OFFSET(vmap_area, va_start);
VMCOREINFO_OFFSET(vmap_area, list);
VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER);
log_buf_vmcoreinfo_setup();
- VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
+ VMCOREINFO_LENGTH(free_area.free, MIGRATE_TYPES);
VMCOREINFO_NUMBER(NR_FREE_PAGES);
VMCOREINFO_NUMBER(PG_lru);
VMCOREINFO_NUMBER(PG_private);
diff --git a/mm/compaction.c b/mm/compaction.c
index bfc93da1c2..7a15f350e4 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1414,19 +1414,21 @@ fast_isolate_freepages(struct compact_control *cc)
for (order = cc->search_order;
!page && order >= 0;
order = next_search_order(cc, order)) {
- struct free_area *area = &cc->zone->free_area[order];
- struct list_head *freelist;
+ struct page_free_list *free =
+ &cc->zone->free_area[order].free[MIGRATE_MOVABLE];
struct page *freepage;
unsigned long flags;
unsigned int order_scanned = 0;
unsigned long high_pfn = 0;

- if (!area->nr_free)
+ spin_lock_irqsave(&cc->zone->lock, flags);
+
+ if (!free->nr) {
+ spin_unlock_irqrestore(&cc->zone->lock, flags);
continue;
+ }

- spin_lock_irqsave(&cc->zone->lock, flags);
- freelist = &area->free_list[MIGRATE_MOVABLE];
- list_for_each_entry_reverse(freepage, freelist, lru) {
+ list_for_each_entry_reverse(freepage, &free->list, lru) {
unsigned long pfn;

order_scanned++;
@@ -1464,7 +1466,7 @@ fast_isolate_freepages(struct compact_control *cc)
}

/* Reorder to so a future search skips recent pages */
- move_freelist_head(freelist, freepage);
+ move_freelist_head(&free->list, freepage);

/* Isolate the page if available */
if (page) {
@@ -1786,11 +1788,11 @@ static unsigned long fast_find_migrateblock(struct compact_control *cc)
unsigned long flags;
struct page *freepage;

- if (!area->nr_free)
+ if (!free_area_nr_free(area))
continue;

spin_lock_irqsave(&cc->zone->lock, flags);
- freelist = &area->free_list[MIGRATE_MOVABLE];
+ freelist = &area->free[MIGRATE_MOVABLE].list;
list_for_each_entry(freepage, freelist, lru) {
unsigned long free_pfn;

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8918c00a91..70e4bcd2f3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -963,20 +963,20 @@ compaction_capture(struct capture_control *capc, struct page *page,
static inline void add_to_free_list(struct page *page, struct zone *zone,
unsigned int order, int migratetype)
{
- struct free_area *area = &zone->free_area[order];
+ struct page_free_list *list = &zone->free_area[order].free[migratetype];

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

/* Used for pages not on another list */
static inline void add_to_free_list_tail(struct page *page, struct zone *zone,
unsigned int order, int migratetype)
{
- struct free_area *area = &zone->free_area[order];
+ struct page_free_list *list = &zone->free_area[order].free[migratetype];

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

/*
@@ -987,9 +987,9 @@ static inline void add_to_free_list_tail(struct page *page, struct zone *zone,
static inline void move_to_free_list(struct page *page, struct zone *zone,
unsigned int order, int migratetype)
{
- struct free_area *area = &zone->free_area[order];
+ struct page_free_list *list = &zone->free_area[order].free[migratetype];

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

static inline void del_page_from_free_list(struct page *page, struct zone *zone,
@@ -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[migratetype]--;
+ zone->free_area[order].free[migratetype].nr--;
}

/*
@@ -2734,7 +2734,7 @@ int find_suitable_fallback(struct free_area *area, unsigned int order,
int i;
int fallback_mt;

- if (area->nr_free == 0)
+ if (free_area_nr_free(area) == 0)
return -1;

*can_steal = false;
@@ -3290,7 +3290,7 @@ void mark_free_pages(struct zone *zone)

for_each_migratetype_order(order, t) {
list_for_each_entry(page,
- &zone->free_area[order].free_list[t], lru) {
+ &zone->free_area[order].free[t].list, lru) {
unsigned long i;

pfn = page_to_pfn(page);
@@ -3886,7 +3886,7 @@ bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
struct free_area *area = &z->free_area[o];
int mt;

- if (!area->nr_free)
+ if (!free_area_nr_free(area))
continue;

for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) {
@@ -6044,7 +6044,7 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
for (type = 0; type < MIGRATE_TYPES; type++) {
if (!free_area_empty(area, type))
types[order] |= 1 << type;
- nr[order] += area->nr_free[type];
+ nr[order] += area->free[type].nr;
}

total += nr[order] << order;
@@ -6624,8 +6624,8 @@ 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[t] = 0;
+ INIT_LIST_HEAD(&zone->free_area[order].free[t].list);
+ zone->free_area[order].free[t].nr = 0;
}
}

diff --git a/mm/page_reporting.c b/mm/page_reporting.c
index 4e45ae95db..c4362b4b0c 100644
--- a/mm/page_reporting.c
+++ b/mm/page_reporting.c
@@ -115,8 +115,7 @@ page_reporting_cycle(struct page_reporting_dev_info *prdev, struct zone *zone,
unsigned int order, unsigned int mt,
struct scatterlist *sgl, unsigned int *offset)
{
- struct free_area *area = &zone->free_area[order];
- struct list_head *list = &area->free_list[mt];
+ struct page_free_list *list = &zone->free_area[order].free[mt];
unsigned int page_len = PAGE_SIZE << order;
struct page *page, *next;
long budget;
@@ -126,7 +125,7 @@ page_reporting_cycle(struct page_reporting_dev_info *prdev, struct zone *zone,
* Perform early check, if free area is empty there is
* nothing to process so we can skip this free_list.
*/
- if (list_empty(list))
+ if (list_empty(&list->list))
return err;

spin_lock_irq(&zone->lock);
@@ -145,10 +144,10 @@ 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[mt], PAGE_REPORTING_CAPACITY * 16);
+ budget = DIV_ROUND_UP(list->nr, PAGE_REPORTING_CAPACITY * 16);

/* loop through free list adding unreported pages to sg list */
- list_for_each_entry_safe(page, next, list, lru) {
+ list_for_each_entry_safe(page, next, &list->list, lru) {
/* We are going to skip over the reported pages. */
if (PageReported(page))
continue;
@@ -183,8 +182,8 @@ page_reporting_cycle(struct page_reporting_dev_info *prdev, struct zone *zone,
* the new head of the free list before we release the
* zone lock.
*/
- if (!list_is_first(&page->lru, list))
- list_rotate_to_front(&page->lru, list);
+ if (!list_is_first(&page->lru, &list->list))
+ list_rotate_to_front(&page->lru, &list->list);

/* release lock before waiting on report processing */
spin_unlock_irq(&zone->lock);
@@ -208,7 +207,7 @@ page_reporting_cycle(struct page_reporting_dev_info *prdev, struct zone *zone,
* Reset next to first entry, the old next isn't valid
* since we dropped the lock to report the pages
*/
- next = list_first_entry(list, struct page, lru);
+ next = list_first_entry(&list->list, struct page, lru);

/* exit on error */
if (err)
@@ -216,8 +215,9 @@ page_reporting_cycle(struct page_reporting_dev_info *prdev, struct zone *zone,
}

/* Rotate any leftover pages to the head of the freelist */
- if (!list_entry_is_head(next, list, lru) && !list_is_first(&next->lru, list))
- list_rotate_to_front(&next->lru, list);
+ if (!list_entry_is_head(next, &list->list, lru) &&
+ !list_is_first(&next->lru, &list->list))
+ list_rotate_to_front(&next->lru, &list->list);

spin_unlock_irq(&zone->lock);

diff --git a/mm/vmstat.c b/mm/vmstat.c
index eb46f99c72..1620dc120f 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1470,7 +1470,7 @@ static void pagetypeinfo_showfree_print(struct seq_file *m,
zone->name,
migratetype_names[mtype]);
for (order = 0; order < MAX_ORDER; ++order) {
- seq_printf(m, "%6zu ", zone->free_area[order].nr_free[mtype]);
+ seq_printf(m, "%6zu ", zone->free_area[order].free[mtype].nr);
spin_unlock_irq(&zone->lock);
cond_resched();
spin_lock_irq(&zone->lock);
--
2.33.0
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