[PATCH RFC 06/15] mm: kill struct mem_cgroup_zone

From: Konstantin Khlebnikov
Date: Wed Feb 15 2012 - 17:57:36 EST

Now struct mem_cgroup_zone always points to one book, either root zone->book or
some from memcg. So this fancy pointer can be replaced with direct pointer to
struct book.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx>
---
mm/vmscan.c | 181 ++++++++++++++++++++++-------------------------------------
1 files changed, 66 insertions(+), 115 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index ba95e83..c59d4f7 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -121,11 +121,6 @@ struct scan_control {
nodemask_t *nodemask;
};

-struct mem_cgroup_zone {
- struct mem_cgroup *mem_cgroup;
- struct zone *zone;
-};
-
#define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))

#ifdef ARCH_HAS_PREFETCH
@@ -170,45 +165,13 @@ static bool global_reclaim(struct scan_control *sc)
{
return !sc->target_mem_cgroup;
}
-
-static bool scanning_global_lru(struct mem_cgroup_zone *mz)
-{
- return !mz->mem_cgroup;
-}
#else
static bool global_reclaim(struct scan_control *sc)
{
return true;
}
-
-static bool scanning_global_lru(struct mem_cgroup_zone *mz)
-{
- return true;
-}
#endif

-static struct zone_reclaim_stat *get_reclaim_stat(struct mem_cgroup_zone *mz)
-{
- if (!scanning_global_lru(mz))
- return &mem_cgroup_zone_book(mz->zone,
- mz->mem_cgroup)->reclaim_stat;
-
- return &mz->zone->book.reclaim_stat;
-}
-
-static unsigned long zone_nr_lru_pages(struct mem_cgroup_zone *mz,
- enum lru_list lru)
-{
- if (!scanning_global_lru(mz))
- return mem_cgroup_zone_nr_lru_pages(mz->mem_cgroup,
- zone_to_nid(mz->zone),
- zone_idx(mz->zone),
- BIT(lru));
-
- return zone_page_state(mz->zone, NR_LRU_BASE + lru);
-}
-
-
/*
* Add a shrinker callback to be called from the vm
*/
@@ -772,7 +735,7 @@ static enum page_references page_check_references(struct page *page,
* shrink_page_list() returns the number of reclaimed pages
*/
static unsigned long shrink_page_list(struct list_head *page_list,
- struct mem_cgroup_zone *mz,
+ struct book *book,
struct scan_control *sc,
int priority,
unsigned long *ret_nr_dirty,
@@ -803,7 +766,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
goto keep;

VM_BUG_ON(PageActive(page));
- VM_BUG_ON(page_zone(page) != mz->zone);
+ VM_BUG_ON(page_zone(page) != book_zone(book));

sc->nr_scanned++;

@@ -1029,7 +992,7 @@ keep_lumpy:
* will encounter the same problem
*/
if (nr_dirty && nr_dirty == nr_congested && global_reclaim(sc))
- zone_set_flag(mz->zone, ZONE_CONGESTED);
+ zone_set_flag(book_zone(book), ZONE_CONGESTED);

free_hot_cold_page_list(&free_pages, 1);

@@ -1144,7 +1107,7 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode, int file)
* Appropriate locks must be held before calling this function.
*
* @nr_to_scan: The number of pages to look through on the list.
- * @mz: The mem_cgroup_zone to pull pages from.
+ * @book The struct book to pull pages from.
* @dst: The temp list to put pages on to.
* @nr_scanned: The number of pages that were scanned.
* @order: The caller's attempted allocation order
@@ -1155,11 +1118,10 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode, int file)
* returns how many pages were moved onto *@dst.
*/
static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
- struct mem_cgroup_zone *mz, struct list_head *dst,
+ struct book *book, struct list_head *dst,
unsigned long *nr_scanned, int order, isolate_mode_t mode,
int active, int file)
{
- struct book *book;
struct list_head *src;
unsigned long nr_taken = 0;
unsigned long nr_lumpy_taken = 0;
@@ -1168,7 +1130,6 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
unsigned long scan;
int lru = LRU_BASE;

- book = mem_cgroup_zone_book(mz->zone, mz->mem_cgroup);
if (active)
lru += LRU_ACTIVE;
if (file)
@@ -1376,11 +1337,11 @@ static int too_many_isolated(struct zone *zone, int file,
}

static noinline_for_stack void
-putback_inactive_pages(struct mem_cgroup_zone *mz,
+putback_inactive_pages(struct book *book,
struct list_head *page_list)
{
- struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(mz);
- struct zone *zone = mz->zone;
+ struct zone_reclaim_stat *reclaim_stat = &book->reclaim_stat;
+ struct zone *zone = book_zone(book);
LIST_HEAD(pages_to_free);

/*
@@ -1427,13 +1388,13 @@ putback_inactive_pages(struct mem_cgroup_zone *mz,
}

static noinline_for_stack void
-update_isolated_counts(struct mem_cgroup_zone *mz,
+update_isolated_counts(struct book *book,
struct list_head *page_list,
unsigned long *nr_anon,
unsigned long *nr_file)
{
- struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(mz);
- struct zone *zone = mz->zone;
+ struct zone_reclaim_stat *reclaim_stat = &book->reclaim_stat;
+ struct zone *zone = book_zone(book);
unsigned int count[NR_LRU_LISTS] = { 0, };
unsigned long nr_active = 0;
struct page *page;
@@ -1517,7 +1478,7 @@ static inline bool should_reclaim_stall(unsigned long nr_taken,
* of reclaimed pages
*/
static noinline_for_stack unsigned long
-shrink_inactive_list(unsigned long nr_to_scan, struct mem_cgroup_zone *mz,
+shrink_inactive_list(unsigned long nr_to_scan, struct book *book,
struct scan_control *sc, int priority, int file)
{
LIST_HEAD(page_list);
@@ -1529,7 +1490,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct mem_cgroup_zone *mz,
unsigned long nr_dirty = 0;
unsigned long nr_writeback = 0;
isolate_mode_t reclaim_mode = ISOLATE_INACTIVE;
- struct zone *zone = mz->zone;
+ struct zone *zone = book_zone(book);

while (unlikely(too_many_isolated(zone, file, sc))) {
congestion_wait(BLK_RW_ASYNC, HZ/10);
@@ -1552,7 +1513,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct mem_cgroup_zone *mz,

spin_lock_irq(&zone->lru_lock);

- nr_taken = isolate_lru_pages(nr_to_scan, mz, &page_list,
+ nr_taken = isolate_lru_pages(nr_to_scan, book, &page_list,
&nr_scanned, sc->order,
reclaim_mode, 0, file);
if (global_reclaim(sc)) {
@@ -1570,20 +1531,20 @@ shrink_inactive_list(unsigned long nr_to_scan, struct mem_cgroup_zone *mz,
return 0;
}

- update_isolated_counts(mz, &page_list, &nr_anon, &nr_file);
+ update_isolated_counts(book, &page_list, &nr_anon, &nr_file);

__mod_zone_page_state(zone, NR_ISOLATED_ANON, nr_anon);
__mod_zone_page_state(zone, NR_ISOLATED_FILE, nr_file);

spin_unlock_irq(&zone->lru_lock);

- nr_reclaimed = shrink_page_list(&page_list, mz, sc, priority,
+ nr_reclaimed = shrink_page_list(&page_list, book, sc, priority,
&nr_dirty, &nr_writeback);

/* Check if we should syncronously wait for writeback */
if (should_reclaim_stall(nr_taken, nr_reclaimed, priority, sc)) {
set_reclaim_mode(priority, sc, true);
- nr_reclaimed += shrink_page_list(&page_list, mz, sc,
+ nr_reclaimed += shrink_page_list(&page_list, book, sc,
priority, &nr_dirty, &nr_writeback);
}

@@ -1593,7 +1554,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct mem_cgroup_zone *mz,
__count_vm_events(KSWAPD_STEAL, nr_reclaimed);
__count_zone_vm_events(PGSTEAL, zone, nr_reclaimed);

- putback_inactive_pages(mz, &page_list);
+ putback_inactive_pages(book, &page_list);

__mod_zone_page_state(zone, NR_ISOLATED_ANON, -nr_anon);
__mod_zone_page_state(zone, NR_ISOLATED_FILE, -nr_file);
@@ -1708,7 +1669,7 @@ static void move_active_pages_to_lru(struct zone *zone,
}

static void shrink_active_list(unsigned long nr_to_scan,
- struct mem_cgroup_zone *mz,
+ struct book *book,
struct scan_control *sc,
int priority, int file)
{
@@ -1719,10 +1680,10 @@ static void shrink_active_list(unsigned long nr_to_scan,
LIST_HEAD(l_active);
LIST_HEAD(l_inactive);
struct page *page;
- struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(mz);
+ struct zone_reclaim_stat *reclaim_stat = &book->reclaim_stat;
unsigned long nr_rotated = 0;
isolate_mode_t reclaim_mode = ISOLATE_ACTIVE;
- struct zone *zone = mz->zone;
+ struct zone *zone = book_zone(book);

lru_add_drain();

@@ -1733,7 +1694,7 @@ static void shrink_active_list(unsigned long nr_to_scan,

spin_lock_irq(&zone->lru_lock);

- nr_taken = isolate_lru_pages(nr_to_scan, mz, &l_hold,
+ nr_taken = isolate_lru_pages(nr_to_scan, book, &l_hold,
&nr_scanned, sc->order,
reclaim_mode, 1, file);
if (global_reclaim(sc))
@@ -1811,12 +1772,11 @@ static void shrink_active_list(unsigned long nr_to_scan,
* Returns true if the zone does not have enough inactive anon pages,
* meaning some active anon pages need to be deactivated.
*/
-static int inactive_anon_is_low(struct mem_cgroup_zone *mz,
+static int inactive_anon_is_low(struct book *book,
struct scan_control *sc)
{
unsigned long active, inactive;
unsigned int ratio;
- struct book *book;

/*
* If we don't have swap space, anonymous page deactivation
@@ -1826,18 +1786,17 @@ static int inactive_anon_is_low(struct mem_cgroup_zone *mz,
return 0;

if (global_reclaim(sc))
- ratio = mz->zone->inactive_ratio;
+ ratio = book_zone(book)->inactive_ratio;
else
ratio = mem_cgroup_inactive_ratio(sc->target_mem_cgroup);

- book = mem_cgroup_zone_book(mz->zone, mz->mem_cgroup);
active = book->pages_count[NR_ACTIVE_ANON];
inactive = book->pages_count[NR_INACTIVE_ANON];

return inactive * ratio < active;
}
#else
-static inline int inactive_anon_is_low(struct mem_cgroup_zone *mz,
+static inline int inactive_anon_is_low(struct book *book,
struct scan_control *sc)
{
return 0;
@@ -1858,40 +1817,38 @@ static inline int inactive_anon_is_low(struct mem_cgroup_zone *mz,
* This uses a different ratio than the anonymous pages, because
* the page cache uses a use-once replacement algorithm.
*/
-static int inactive_file_is_low(struct mem_cgroup_zone *mz)
+static int inactive_file_is_low(struct book *book)
{
unsigned long active, inactive;
- struct book *book;

- book = mem_cgroup_zone_book(mz->zone, mz->mem_cgroup);
active = book->pages_count[NR_ACTIVE_FILE];
inactive = book->pages_count[NR_INACTIVE_FILE];

return inactive < active;
}

-static int inactive_list_is_low(struct mem_cgroup_zone *mz,
+static int inactive_list_is_low(struct book *book,
struct scan_control *sc, int file)
{
if (file)
- return inactive_file_is_low(mz);
+ return inactive_file_is_low(book);
else
- return inactive_anon_is_low(mz, sc);
+ return inactive_anon_is_low(book, sc);
}

static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan,
- struct mem_cgroup_zone *mz,
+ struct book *book,
struct scan_control *sc, int priority)
{
int file = is_file_lru(lru);

if (is_active_lru(lru)) {
- if (inactive_list_is_low(mz, sc, file))
- shrink_active_list(nr_to_scan, mz, sc, priority, file);
+ if (inactive_list_is_low(book, sc, file))
+ shrink_active_list(nr_to_scan, book, sc, priority, file);
return 0;
}

- return shrink_inactive_list(nr_to_scan, mz, sc, priority, file);
+ return shrink_inactive_list(nr_to_scan, book, sc, priority, file);
}

static int vmscan_swappiness(struct scan_control *sc)
@@ -1909,17 +1866,18 @@ static int vmscan_swappiness(struct scan_control *sc)
*
* nr[0] = anon pages to scan; nr[1] = file pages to scan
*/
-static void get_scan_count(struct mem_cgroup_zone *mz, struct scan_control *sc,
+static void get_scan_count(struct book *book, struct scan_control *sc,
unsigned long *nr, int priority)
{
unsigned long anon, file, free;
unsigned long anon_prio, file_prio;
unsigned long ap, fp;
- struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(mz);
+ struct zone_reclaim_stat *reclaim_stat = &book->reclaim_stat;
u64 fraction[2], denominator;
enum lru_list lru;
int noswap = 0;
bool force_scan = false;
+ struct zone *zone = book_zone(book);

/*
* If the zone or memcg is small, nr[l] can be 0. This
@@ -1931,7 +1889,7 @@ static void get_scan_count(struct mem_cgroup_zone *mz, struct scan_control *sc,
* latencies, so it's better to scan a minimum amount there as
* well.
*/
- if (current_is_kswapd() && mz->zone->all_unreclaimable)
+ if (current_is_kswapd() && zone->all_unreclaimable)
force_scan = true;
if (!global_reclaim(sc))
force_scan = true;
@@ -1945,16 +1903,16 @@ static void get_scan_count(struct mem_cgroup_zone *mz, struct scan_control *sc,
goto out;
}

- anon = zone_nr_lru_pages(mz, LRU_ACTIVE_ANON) +
- zone_nr_lru_pages(mz, LRU_INACTIVE_ANON);
- file = zone_nr_lru_pages(mz, LRU_ACTIVE_FILE) +
- zone_nr_lru_pages(mz, LRU_INACTIVE_FILE);
+ anon = book->pages_count[LRU_ACTIVE_ANON] +
+ book->pages_count[LRU_INACTIVE_ANON];
+ file = book->pages_count[LRU_ACTIVE_FILE] +
+ book->pages_count[LRU_INACTIVE_FILE];

if (global_reclaim(sc)) {
- free = zone_page_state(mz->zone, NR_FREE_PAGES);
+ free = zone_page_state(zone, NR_FREE_PAGES);
/* If we have very few page cache pages,
force-scan anon pages. */
- if (unlikely(file + free <= high_wmark_pages(mz->zone))) {
+ if (unlikely(file + free <= high_wmark_pages(zone))) {
fraction[0] = 1;
fraction[1] = 0;
denominator = 1;
@@ -1980,7 +1938,7 @@ static void get_scan_count(struct mem_cgroup_zone *mz, struct scan_control *sc,
*
* anon in [0], file in [1]
*/
- spin_lock_irq(&mz->zone->lru_lock);
+ spin_lock_irq(&zone->lru_lock);
if (unlikely(reclaim_stat->recent_scanned[0] > anon / 4)) {
reclaim_stat->recent_scanned[0] /= 2;
reclaim_stat->recent_rotated[0] /= 2;
@@ -2001,7 +1959,7 @@ static void get_scan_count(struct mem_cgroup_zone *mz, struct scan_control *sc,

fp = (file_prio + 1) * (reclaim_stat->recent_scanned[1] + 1);
fp /= reclaim_stat->recent_rotated[1] + 1;
- spin_unlock_irq(&mz->zone->lru_lock);
+ spin_unlock_irq(&zone->lru_lock);

fraction[0] = ap;
fraction[1] = fp;
@@ -2011,7 +1969,7 @@ out:
int file = is_file_lru(lru);
unsigned long scan;

- scan = zone_nr_lru_pages(mz, lru);
+ scan = book->pages_count[lru];
if (priority || noswap) {
scan >>= priority;
if (!scan && force_scan)
@@ -2029,7 +1987,7 @@ out:
* back to the allocator and call try_to_compact_zone(), we ensure that
* there are enough free pages for it to be likely successful
*/
-static inline bool should_continue_reclaim(struct mem_cgroup_zone *mz,
+static inline bool should_continue_reclaim(struct book *book,
unsigned long nr_reclaimed,
unsigned long nr_scanned,
struct scan_control *sc)
@@ -2069,15 +2027,15 @@ static inline bool should_continue_reclaim(struct mem_cgroup_zone *mz,
* inactive lists are large enough, continue reclaiming
*/
pages_for_compaction = (2UL << sc->order);
- inactive_lru_pages = zone_nr_lru_pages(mz, LRU_INACTIVE_FILE);
+ inactive_lru_pages = book->pages_count[LRU_INACTIVE_FILE];
if (nr_swap_pages > 0)
- inactive_lru_pages += zone_nr_lru_pages(mz, LRU_INACTIVE_ANON);
+ inactive_lru_pages += book->pages_count[LRU_INACTIVE_ANON];
if (sc->nr_reclaimed < pages_for_compaction &&
inactive_lru_pages > pages_for_compaction)
return true;

/* If compaction would go ahead or the allocation would succeed, stop */
- switch (compaction_suitable(mz->zone, sc->order)) {
+ switch (compaction_suitable(book_zone(book), sc->order)) {
case COMPACT_PARTIAL:
case COMPACT_CONTINUE:
return false;
@@ -2089,8 +2047,8 @@ static inline bool should_continue_reclaim(struct mem_cgroup_zone *mz,
/*
* This is a basic per-zone page freer. Used by both kswapd and direct reclaim.
*/
-static void shrink_mem_cgroup_zone(int priority, struct mem_cgroup_zone *mz,
- struct scan_control *sc)
+static void shrink_book(int priority, struct book *book,
+ struct scan_control *sc)
{
unsigned long nr[NR_LRU_LISTS];
unsigned long nr_to_scan;
@@ -2102,7 +2060,7 @@ static void shrink_mem_cgroup_zone(int priority, struct mem_cgroup_zone *mz,
restart:
nr_reclaimed = 0;
nr_scanned = sc->nr_scanned;
- get_scan_count(mz, sc, nr, priority);
+ get_scan_count(book, sc, nr, priority);

blk_start_plug(&plug);
while (nr[LRU_INACTIVE_ANON] || nr[LRU_ACTIVE_FILE] ||
@@ -2114,7 +2072,7 @@ restart:
nr[lru] -= nr_to_scan;

nr_reclaimed += shrink_list(lru, nr_to_scan,
- mz, sc, priority);
+ book, sc, priority);
}
}
/*
@@ -2135,11 +2093,11 @@ restart:
* Even if we did not try to evict anon pages at all, we want to
* rebalance the anon lru active/inactive ratio.
*/
- if (inactive_anon_is_low(mz, sc))
- shrink_active_list(SWAP_CLUSTER_MAX, mz, sc, priority, 0);
+ if (inactive_anon_is_low(book, sc))
+ shrink_active_list(SWAP_CLUSTER_MAX, book, sc, priority, 0);

/* reclaim/compaction might need reclaim to continue */
- if (should_continue_reclaim(mz, nr_reclaimed,
+ if (should_continue_reclaim(book, nr_reclaimed,
sc->nr_scanned - nr_scanned, sc))
goto restart;

@@ -2155,18 +2113,17 @@ static void shrink_zone(int priority, struct zone *zone,
.priority = priority,
};
struct mem_cgroup *memcg;
+ struct book *book;

memcg = mem_cgroup_iter(root, NULL, &reclaim);
do {
- struct mem_cgroup_zone mz = {
- .mem_cgroup = memcg,
- .zone = zone,
- };
+ book = mem_cgroup_zone_book(zone, memcg);

if (!global_reclaim(sc))
sc->current_mem_cgroup = memcg;

- shrink_mem_cgroup_zone(priority, &mz, sc);
+ shrink_book(priority, book, sc);
+
/*
* Limit reclaim has historically picked one memcg and
* scanned it with decreasing priority levels until
@@ -2483,10 +2440,7 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *memcg,
.target_mem_cgroup = memcg,
.current_mem_cgroup = memcg,
};
- struct mem_cgroup_zone mz = {
- .mem_cgroup = memcg,
- .zone = zone,
- };
+ struct book *book = mem_cgroup_zone_book(zone, memcg);

sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
(GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
@@ -2502,7 +2456,7 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *memcg,
* will pick up pages from other mem cgroup's as well. We hack
* the priority and make it zero.
*/
- shrink_mem_cgroup_zone(0, &mz, &sc);
+ shrink_book(0, book, &sc);

trace_mm_vmscan_memcg_softlimit_reclaim_end(sc.nr_reclaimed);

@@ -2563,13 +2517,10 @@ static void age_active_anon(struct zone *zone, struct scan_control *sc,

memcg = mem_cgroup_iter(NULL, NULL, NULL);
do {
- struct mem_cgroup_zone mz = {
- .mem_cgroup = memcg,
- .zone = zone,
- };
+ struct book *book = mem_cgroup_zone_book(zone, memcg);

- if (inactive_anon_is_low(&mz, sc))
- shrink_active_list(SWAP_CLUSTER_MAX, &mz,
+ if (inactive_anon_is_low(book, sc))
+ shrink_active_list(SWAP_CLUSTER_MAX, book,
sc, priority, 0);

memcg = mem_cgroup_iter(NULL, memcg, NULL);

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