]> git.proxmox.com Git - mirror_ubuntu-hirsute-kernel.git/commitdiff
mm/swap.c: serialize memcg changes in pagevec_lru_move_fn
authorAlex Shi <alex.shi@linux.alibaba.com>
Tue, 15 Dec 2020 20:34:25 +0000 (12:34 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 15 Dec 2020 22:48:04 +0000 (14:48 -0800)
Hugh Dickins' found a memcg change bug on original version: If we want to
change the pgdat->lru_lock to memcg's lruvec lock, we have to serialize
mem_cgroup_move_account during pagevec_lru_move_fn.  The possible bad
scenario would like:

cpu 0 cpu 1
lruvec = mem_cgroup_page_lruvec()
if (!isolate_lru_page())
mem_cgroup_move_account

spin_lock_irqsave(&lruvec->lru_lock <== wrong lock.

So we need TestClearPageLRU to block isolate_lru_page(), that serializes
the memcg change.  and then removing the PageLRU check in move_fn callee
as the consequence.

__pagevec_lru_add_fn() is different from the others, because the pages it
deals with are, by definition, not yet on the lru.  TestClearPageLRU is
not needed and would not work, so __pagevec_lru_add() goes its own way.

Link: https://lkml.kernel.org/r/1604566549-62481-17-git-send-email-alex.shi@linux.alibaba.com
Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexander Duyck <alexander.duyck@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: "Chen, Rong A" <rong.a.chen@intel.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mika Penttilä <mika.penttila@nextfour.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/swap.c

index c3187d04f9b2ba12a5eaee95b30d6b19881a6fd8..d952af77005340fce28ec1e482ee3ac7a2cf3617 100644 (file)
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -222,8 +222,14 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
                        spin_lock_irqsave(&pgdat->lru_lock, flags);
                }
 
+               /* block memcg migration during page moving between lru */
+               if (!TestClearPageLRU(page))
+                       continue;
+
                lruvec = mem_cgroup_page_lruvec(page, pgdat);
                (*move_fn)(page, lruvec);
+
+               SetPageLRU(page);
        }
        if (pgdat)
                spin_unlock_irqrestore(&pgdat->lru_lock, flags);
@@ -233,7 +239,7 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
 
 static void pagevec_move_tail_fn(struct page *page, struct lruvec *lruvec)
 {
-       if (PageLRU(page) && !PageUnevictable(page)) {
+       if (!PageUnevictable(page)) {
                del_page_from_lru_list(page, lruvec, page_lru(page));
                ClearPageActive(page);
                add_page_to_lru_list_tail(page, lruvec, page_lru(page));
@@ -306,7 +312,7 @@ void lru_note_cost_page(struct page *page)
 
 static void __activate_page(struct page *page, struct lruvec *lruvec)
 {
-       if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
+       if (!PageActive(page) && !PageUnevictable(page)) {
                int lru = page_lru_base_type(page);
                int nr_pages = thp_nr_pages(page);
 
@@ -362,7 +368,8 @@ static void activate_page(struct page *page)
 
        page = compound_head(page);
        spin_lock_irq(&pgdat->lru_lock);
-       __activate_page(page, mem_cgroup_page_lruvec(page, pgdat));
+       if (PageLRU(page))
+               __activate_page(page, mem_cgroup_page_lruvec(page, pgdat));
        spin_unlock_irq(&pgdat->lru_lock);
 }
 #endif
@@ -519,9 +526,6 @@ static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec)
        bool active;
        int nr_pages = thp_nr_pages(page);
 
-       if (!PageLRU(page))
-               return;
-
        if (PageUnevictable(page))
                return;
 
@@ -562,7 +566,7 @@ static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec)
 
 static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec)
 {
-       if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) {
+       if (PageActive(page) && !PageUnevictable(page)) {
                int lru = page_lru_base_type(page);
                int nr_pages = thp_nr_pages(page);
 
@@ -579,7 +583,7 @@ static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec)
 
 static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec)
 {
-       if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) &&
+       if (PageAnon(page) && PageSwapBacked(page) &&
            !PageSwapCache(page) && !PageUnevictable(page)) {
                bool active = PageActive(page);
                int nr_pages = thp_nr_pages(page);
@@ -1021,7 +1025,29 @@ static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec)
  */
 void __pagevec_lru_add(struct pagevec *pvec)
 {
-       pagevec_lru_move_fn(pvec, __pagevec_lru_add_fn);
+       int i;
+       struct pglist_data *pgdat = NULL;
+       struct lruvec *lruvec;
+       unsigned long flags = 0;
+
+       for (i = 0; i < pagevec_count(pvec); i++) {
+               struct page *page = pvec->pages[i];
+               struct pglist_data *pagepgdat = page_pgdat(page);
+
+               if (pagepgdat != pgdat) {
+                       if (pgdat)
+                               spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+                       pgdat = pagepgdat;
+                       spin_lock_irqsave(&pgdat->lru_lock, flags);
+               }
+
+               lruvec = mem_cgroup_page_lruvec(page, pgdat);
+               __pagevec_lru_add_fn(page, lruvec);
+       }
+       if (pgdat)
+               spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+       release_pages(pvec->pages, pvec->nr);
+       pagevec_reinit(pvec);
 }
 
 /**