Andrea Arcangeli suggested to make split queue per-node to improve
scalability. Let's do it.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Suggested-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
---
include/linux/mmzone.h | 6 ++++++
mm/huge_memory.c | 49 ++++++++++++++++++++++++++-----------------------
mm/page_alloc.c | 5 +++++
3 files changed, 37 insertions(+), 23 deletions(-)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 33bb1b19273e..7b6c2cfee390 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -682,6 +682,12 @@ typedef struct pglist_data {
*/
unsigned long first_deferred_pfn;
#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ spinlock_t split_queue_lock;
+ struct list_head split_queue;
+ unsigned long split_queue_len;
+#endif
} pg_data_t;
#define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 2d1ffe9d0e26..769ea8db5771 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -138,9 +138,6 @@ static struct khugepaged_scan khugepaged_scan = {
.mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head),
};
-static DEFINE_SPINLOCK(split_queue_lock);
-static LIST_HEAD(split_queue);
-static unsigned long split_queue_len;
static struct shrinker deferred_split_shrinker;
static void set_recommended_min_free_kbytes(void)
@@ -3358,6 +3355,7 @@ int total_mapcount(struct page *page)
int split_huge_page_to_list(struct page *page, struct list_head *list)
{
struct page *head = compound_head(page);
+ struct pglist_data *pgdata = NODE_DATA(page_to_nid(head));
struct anon_vma *anon_vma;
int count, mapcount, ret;
bool mlocked;
@@ -3401,19 +3399,19 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
lru_add_drain();
/* Prevent deferred_split_scan() touching ->_count */
- spin_lock_irqsave(&split_queue_lock, flags);
+ spin_lock_irqsave(&pgdata->split_queue_lock, flags);
count = page_count(head);
mapcount = total_mapcount(head);
if (!mapcount && count == 1) {
if (!list_empty(page_deferred_list(head))) {
- split_queue_len--;
+ pgdata->split_queue_len--;
list_del(page_deferred_list(head));
}
- spin_unlock_irqrestore(&split_queue_lock, flags);
+ spin_unlock_irqrestore(&pgdata->split_queue_lock, flags);
__split_huge_page(page, list);
ret = 0;
} else if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) {
- spin_unlock_irqrestore(&split_queue_lock, flags);
+ spin_unlock_irqrestore(&pgdata->split_queue_lock, flags);
pr_alert("total_mapcount: %u, page_count(): %u\n",
mapcount, count);
if (PageTail(page))
@@ -3421,7 +3419,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
dump_page(page, "total_mapcount(head) > 0");
BUG();
} else {
- spin_unlock_irqrestore(&split_queue_lock, flags);
+ spin_unlock_irqrestore(&pgdata->split_queue_lock, flags);
unfreeze_page(anon_vma, head);
ret = -EBUSY;
}
@@ -3436,52 +3434,56 @@ out:
void free_transhuge_page(struct page *page)
{
+ struct pglist_data *pgdata = NODE_DATA(page_to_nid(page));
unsigned long flags;
- spin_lock_irqsave(&split_queue_lock, flags);
+ spin_lock_irqsave(&pgdata->split_queue_lock, flags);
if (!list_empty(page_deferred_list(page))) {
- split_queue_len--;
+ pgdata->split_queue_len--;
list_del(page_deferred_list(page));
}
- spin_unlock_irqrestore(&split_queue_lock, flags);
+ spin_unlock_irqrestore(&pgdata->split_queue_lock, flags);
free_compound_page(page);
}
void deferred_split_huge_page(struct page *page)
{
+ struct pglist_data *pgdata = NODE_DATA(page_to_nid(page));
unsigned long flags;
VM_BUG_ON_PAGE(!PageTransHuge(page), page);
- spin_lock_irqsave(&split_queue_lock, flags);
+ spin_lock_irqsave(&pgdata->split_queue_lock, flags);
if (list_empty(page_deferred_list(page))) {
- list_add_tail(page_deferred_list(page), &split_queue);
- split_queue_len++;
+ list_add_tail(page_deferred_list(page), &pgdata->split_queue);
+ pgdata->split_queue_len++;
}
- spin_unlock_irqrestore(&split_queue_lock, flags);
+ spin_unlock_irqrestore(&pgdata->split_queue_lock, flags);
}
static unsigned long deferred_split_count(struct shrinker *shrink,
struct shrink_control *sc)
{
+ struct pglist_data *pgdata = NODE_DATA(sc->nid);
/*
* Split a page from split_queue will free up at least one page,
* at most HPAGE_PMD_NR - 1. We don't track exact number.
* Let's use HPAGE_PMD_NR / 2 as ballpark.
*/
- return ACCESS_ONCE(split_queue_len) * HPAGE_PMD_NR / 2;
+ return ACCESS_ONCE(pgdata->split_queue_len) * HPAGE_PMD_NR / 2;
}
static unsigned long deferred_split_scan(struct shrinker *shrink,
struct shrink_control *sc)
{
+ struct pglist_data *pgdata = NODE_DATA(sc->nid);
unsigned long flags;
LIST_HEAD(list), *pos, *next;
struct page *page;
int split = 0;
- spin_lock_irqsave(&split_queue_lock, flags);
- list_splice_init(&split_queue, &list);
+ spin_lock_irqsave(&pgdata->split_queue_lock, flags);
+ list_splice_init(&pgdata->split_queue, &list);
/* Take pin on all head pages to avoid freeing them under us */
list_for_each_safe(pos, next, &list) {
@@ -3490,10 +3492,10 @@ static unsigned long deferred_split_scan(struct shrinker *shrink,
/* race with put_compound_page() */
if (!get_page_unless_zero(page)) {
list_del_init(page_deferred_list(page));
- split_queue_len--;
+ pgdata->split_queue_len--;
}
}
- spin_unlock_irqrestore(&split_queue_lock, flags);
+ spin_unlock_irqrestore(&pgdata->split_queue_lock, flags);
list_for_each_safe(pos, next, &list) {
page = list_entry((void *)pos, struct page, mapping);
@@ -3505,9 +3507,9 @@ static unsigned long deferred_split_scan(struct shrinker *shrink,
put_page(page);
}
- spin_lock_irqsave(&split_queue_lock, flags);
- list_splice_tail(&list, &split_queue);
- spin_unlock_irqrestore(&split_queue_lock, flags);
+ spin_lock_irqsave(&pgdata->split_queue_lock, flags);
+ list_splice_tail(&list, &pgdata->split_queue);
+ spin_unlock_irqrestore(&pgdata->split_queue_lock, flags);
return split * HPAGE_PMD_NR / 2;
}
@@ -3516,6 +3518,7 @@ static struct shrinker deferred_split_shrinker = {
.count_objects = deferred_split_count,
.scan_objects = deferred_split_scan,
.seeks = DEFAULT_SEEKS,
+ .flags = SHRINKER_NUMA_AWARE,
};
#ifdef CONFIG_DEBUG_FS
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 63358d9f9aa9..ea2c4d3e0c03 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5210,6 +5210,11 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
pgdat->numabalancing_migrate_nr_pages = 0;
pgdat->numabalancing_migrate_next_window = jiffies;
#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ spin_lock_init(&pgdat->split_queue_lock);
+ INIT_LIST_HEAD(&pgdat->split_queue);
+ pgdat->split_queue_len = 0;
+#endif
init_waitqueue_head(&pgdat->kswapd_wait);
init_waitqueue_head(&pgdat->pfmemalloc_wait);
pgdat_page_ext_init(pgdat);
--
2.7.0.rc3
--
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