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mm/swap.c: serialize memcg changes in pagevec_lru_move_fn

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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>
This commit is contained in:
Alex Shi 2020-12-15 12:34:25 -08:00 committed by Linus Torvalds
parent 9df4131439
commit fc574c2355
1 changed files with 35 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
mm/swap.c
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@ -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);
}
/**