[PATCH v9 07/20] mm/lru: introduce TestClearPageLRU

Alex Shi
2020-03-02T11:00:17Z

Combined PageLRU check and ClearPageLRU into one function by new
introduced func TestClearPageLRU. This function will be used as page
isolation precondition.

No functional change yet.

Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Cc: cgroups@vger.kernel.org
Cc: linux-mm@kvack.org
---
include/linux/page-flags.h | 1 +
mm/memcontrol.c | 4 ++--
mm/mlock.c | 3 +--
mm/swap.c | 8 ++------
mm/vmscan.c | 19 +++++++++----------
5 files changed, 15 insertions(+), 20 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 1bf83c8fcaa7..5cb155f3191e 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -318,6 +318,7 @@ static inline void page_init_poison(struct page *page, size_t size)
PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
__CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
+ TESTCLEARFLAG(LRU, lru, PF_HEAD)
PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
TESTCLEARFLAG(Active, active, PF_HEAD)
PAGEFLAG(Workingset, workingset, PF_HEAD)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 875e2aebcde7..f8419f3436a8 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2588,9 +2588,8 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
pgdat = page_pgdat(page);
spin_lock_irq(&pgdat->lru_lock);

- if (PageLRU(page)) {
+ if (TestClearPageLRU(page)) {
lruvec = mem_cgroup_page_lruvec(page, pgdat);
- ClearPageLRU(page);
del_page_from_lru_list(page, lruvec, page_lru(page));
} else
spin_unlock_irq(&pgdat->lru_lock);
@@ -2613,6 +2612,7 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,

if (lrucare && lruvec) {
lruvec = mem_cgroup_page_lruvec(page, pgdat);
+
VM_BUG_ON_PAGE(PageLRU(page), page);
SetPageLRU(page);
add_page_to_lru_list(page, lruvec, page_lru(page));
diff --git a/mm/mlock.c b/mm/mlock.c
index a72c1eeded77..03b3a5d99ad7 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -108,13 +108,12 @@ void mlock_vma_page(struct page *page)
*/
static bool __munlock_isolate_lru_page(struct page *page, bool getpage)
{
- if (PageLRU(page)) {
+ if (TestClearPageLRU(page)) {
struct lruvec *lruvec;

lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
if (getpage)
get_page(page);
- ClearPageLRU(page);
del_page_from_lru_list(page, lruvec, page_lru(page));
return true;
}
diff --git a/mm/swap.c b/mm/swap.c
index 1ac24fc35d6b..8e71bdd04a1a 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -59,15 +59,13 @@
*/
static void __page_cache_release(struct page *page)
{
- if (PageLRU(page)) {
+ if (TestClearPageLRU(page)) {
pg_data_t *pgdat = page_pgdat(page);
struct lruvec *lruvec;
unsigned long flags;

spin_lock_irqsave(&pgdat->lru_lock, flags);
lruvec = mem_cgroup_page_lruvec(page, pgdat);
- VM_BUG_ON_PAGE(!PageLRU(page), page);
- __ClearPageLRU(page);
del_page_from_lru_list(page, lruvec, page_off_lru(page));
spin_unlock_irqrestore(&pgdat->lru_lock, flags);
}
@@ -831,7 +829,7 @@ void release_pages(struct page **pages, int nr)
continue;
}

- if (PageLRU(page)) {
+ if (TestClearPageLRU(page)) {
struct pglist_data *pgdat = page_pgdat(page);

if (pgdat != locked_pgdat) {
@@ -844,8 +842,6 @@ void release_pages(struct page **pages, int nr)
}

lruvec = mem_cgroup_page_lruvec(page, locked_pgdat);
- VM_BUG_ON_PAGE(!PageLRU(page), page);
- __ClearPageLRU(page);
del_page_from_lru_list(page, lruvec, page_off_lru(page));
}

diff --git a/mm/vmscan.c b/mm/vmscan.c
index dcdd33f65f43..8958454d50fe 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1751,21 +1751,20 @@ int isolate_lru_page(struct page *page)
VM_BUG_ON_PAGE(!page_count(page), page);
WARN_RATELIMIT(PageTail(page), "trying to isolate tail page");

- if (PageLRU(page)) {
+ get_page(page);
+ if (TestClearPageLRU(page)) {
pg_data_t *pgdat = page_pgdat(page);
struct lruvec *lruvec;
+ int lru = page_lru(page);

- spin_lock_irq(&pgdat->lru_lock);
lruvec = mem_cgroup_page_lruvec(page, pgdat);
- if (PageLRU(page)) {
- int lru = page_lru(page);
- get_page(page);
- ClearPageLRU(page);
- del_page_from_lru_list(page, lruvec, lru);
- ret = 0;
- }
+ spin_lock_irq(&pgdat->lru_lock);
+ del_page_from_lru_list(page, lruvec, lru);
spin_unlock_irq(&pgdat->lru_lock);
- }
+ ret = 0;
+ } else
+ put_page(page);
+
return ret;
}

--
1.8.3.1