From: Alex Shi alex.shi@linux.alibaba.com
[ Upstream commit 3db19aa39bac33f2e850fa1ddd67be29b192e51f ]
In the func munlock_vma_page, comments mentained lru_lock needed for serialization with split_huge_pages. But the page must be PageLocked as well as pages in split_huge_page series funcs. Thus the PageLocked is enough to serialize both funcs.
Further more, Hugh Dickins pointed: before splitting in split_huge_page_to_list, the page was unmap_page() to remove pmd/ptes which protect the page from munlock. Thus, no needs to guard __split_huge_page_tail for mlock clean, just keep the lru_lock there for isolation purpose.
LKP found a preempt issue on __mod_zone_page_state which need change to mod_zone_page_state. Thanks!
Link: https://lkml.kernel.org/r/1604566549-62481-13-git-send-email-alex.shi@linux.... 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: Kirill A. Shutemov kirill.shutemov@linux.intel.com 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.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 Stable-dep-of: 829ae0f81ce0 ("mm: migrate: fix THP's mapcount on isolation") Signed-off-by: Sasha Levin sashal@kernel.org --- mm/mlock.c | 26 +++++--------------------- 1 file changed, 5 insertions(+), 21 deletions(-)
diff --git a/mm/mlock.c b/mm/mlock.c index 884b1216da6a..796c726a0407 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -187,40 +187,24 @@ static void __munlock_isolation_failed(struct page *page) unsigned int munlock_vma_page(struct page *page) { int nr_pages; - pg_data_t *pgdat = page_pgdat(page);
/* For try_to_munlock() and to serialize with page migration */ BUG_ON(!PageLocked(page)); - VM_BUG_ON_PAGE(PageTail(page), page);
- /* - * Serialize with any parallel __split_huge_page_refcount() which - * might otherwise copy PageMlocked to part of the tail pages before - * we clear it in the head page. It also stabilizes thp_nr_pages(). - */ - spin_lock_irq(&pgdat->lru_lock); - if (!TestClearPageMlocked(page)) { /* Potentially, PTE-mapped THP: do not skip the rest PTEs */ - nr_pages = 1; - goto unlock_out; + return 0; }
nr_pages = thp_nr_pages(page); - __mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages); + mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
- if (__munlock_isolate_lru_page(page, true)) { - spin_unlock_irq(&pgdat->lru_lock); + if (!isolate_lru_page(page)) __munlock_isolated_page(page); - goto out; - } - __munlock_isolation_failed(page); - -unlock_out: - spin_unlock_irq(&pgdat->lru_lock); + else + __munlock_isolation_failed(page);
-out: return nr_pages - 1; }