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[23.128.96.18]) by mx.google.com with ESMTP id do11si2025701ejc.450.2020.06.10.23.22.14; Wed, 10 Jun 2020 23:22:36 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=alibaba.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726803AbgFKGRm (ORCPT + 99 others); Thu, 11 Jun 2020 02:17:42 -0400 Received: from out30-44.freemail.mail.aliyun.com ([115.124.30.44]:41616 "EHLO out30-44.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726654AbgFKGRQ (ORCPT ); Thu, 11 Jun 2020 02:17:16 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R121e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04407;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=17;SR=0;TI=SMTPD_---0U.EqdSY_1591856229; Received: from localhost(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0U.EqdSY_1591856229) by smtp.aliyun-inc.com(127.0.0.1); Thu, 11 Jun 2020 14:17:10 +0800 From: Alex Shi To: akpm@linux-foundation.org, mgorman@techsingularity.net, tj@kernel.org, hughd@google.com, khlebnikov@yandex-team.ru, daniel.m.jordan@oracle.com, yang.shi@linux.alibaba.com, willy@infradead.org, hannes@cmpxchg.org, lkp@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, shakeelb@google.com, iamjoonsoo.kim@lge.com, richard.weiyang@gmail.com Cc: "Kirill A. Shutemov" Subject: [PATCH v12 11/16] mm/mlock: reorder isolation sequence during munlock Date: Thu, 11 Jun 2020 14:16:44 +0800 Message-Id: <1591856209-166869-12-git-send-email-alex.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1591856209-166869-1-git-send-email-alex.shi@linux.alibaba.com> References: <1591856209-166869-1-git-send-email-alex.shi@linux.alibaba.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch reorder the isolation steps during munlock, move the lru lock to guard each pages, unfold __munlock_isolate_lru_page func, to do the preparation for lru lock change. __split_huge_page_refcount doesn't exist, but we still have to guard PageMlocked and PageLRU in __split_huge_page_tail. [lkp@intel.com: found a sleeping function bug ... at mm/rmap.c] Signed-off-by: Alex Shi Cc: Kirill A. Shutemov Cc: Andrew Morton Cc: Johannes Weiner Cc: Matthew Wilcox Cc: Hugh Dickins Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- mm/mlock.c | 93 ++++++++++++++++++++++++++++++++++---------------------------- 1 file changed, 51 insertions(+), 42 deletions(-) diff --git a/mm/mlock.c b/mm/mlock.c index 228ba5a8e0a5..7098be122966 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -103,25 +103,6 @@ void mlock_vma_page(struct page *page) } /* - * Isolate a page from LRU with optional get_page() pin. - * Assumes lru_lock already held and page already pinned. - */ -static bool __munlock_isolate_lru_page(struct page *page, bool getpage) -{ - if (TestClearPageLRU(page)) { - struct lruvec *lruvec; - - lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page)); - if (getpage) - get_page(page); - del_page_from_lru_list(page, lruvec, page_lru(page)); - return true; - } - - return false; -} - -/* * Finish munlock after successful page isolation * * Page must be locked. This is a wrapper for try_to_munlock() @@ -181,6 +162,7 @@ static void __munlock_isolation_failed(struct page *page) unsigned int munlock_vma_page(struct page *page) { int nr_pages; + bool clearlru = false; pg_data_t *pgdat = page_pgdat(page); /* For try_to_munlock() and to serialize with page migration */ @@ -189,32 +171,42 @@ unsigned int munlock_vma_page(struct page *page) VM_BUG_ON_PAGE(PageTail(page), page); /* - * Serialize with any parallel __split_huge_page_refcount() which + * Serialize with any parallel __split_huge_page_tail() which * might otherwise copy PageMlocked to part of the tail pages before * we clear it in the head page. It also stabilizes hpage_nr_pages(). */ + get_page(page); spin_lock_irq(&pgdat->lru_lock); + clearlru = TestClearPageLRU(page); if (!TestClearPageMlocked(page)) { - /* Potentially, PTE-mapped THP: do not skip the rest PTEs */ - nr_pages = 1; - goto unlock_out; + if (clearlru) + SetPageLRU(page); + /* + * Potentially, PTE-mapped THP: do not skip the rest PTEs + * Reuse lock as memory barrier for release_pages racing. + */ + spin_unlock_irq(&pgdat->lru_lock); + put_page(page); + return 0; } nr_pages = hpage_nr_pages(page); __mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages); - if (__munlock_isolate_lru_page(page, true)) { + if (clearlru) { + struct lruvec *lruvec; + + lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page)); + del_page_from_lru_list(page, lruvec, page_lru(page)); spin_unlock_irq(&pgdat->lru_lock); __munlock_isolated_page(page); - goto out; + } else { + spin_unlock_irq(&pgdat->lru_lock); + put_page(page); + __munlock_isolation_failed(page); } - __munlock_isolation_failed(page); - -unlock_out: - spin_unlock_irq(&pgdat->lru_lock); -out: return nr_pages - 1; } @@ -297,34 +289,51 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone) pagevec_init(&pvec_putback); /* Phase 1: page isolation */ - spin_lock_irq(&zone->zone_pgdat->lru_lock); for (i = 0; i < nr; i++) { struct page *page = pvec->pages[i]; + struct lruvec *lruvec; + bool clearlru; - if (TestClearPageMlocked(page)) { - /* - * We already have pin from follow_page_mask() - * so we can spare the get_page() here. - */ - if (__munlock_isolate_lru_page(page, false)) - continue; - else - __munlock_isolation_failed(page); - } else { + clearlru = TestClearPageLRU(page); + spin_lock_irq(&zone->zone_pgdat->lru_lock); + + if (!TestClearPageMlocked(page)) { delta_munlocked++; + if (clearlru) + SetPageLRU(page); + goto putback; + } + + if (!clearlru) { + __munlock_isolation_failed(page); + goto putback; } /* + * Isolate this page. + * We already have pin from follow_page_mask() + * so we can spare the get_page() here. + */ + lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page)); + del_page_from_lru_list(page, lruvec, page_lru(page)); + spin_unlock_irq(&zone->zone_pgdat->lru_lock); + continue; + + /* * We won't be munlocking this page in the next phase * but we still need to release the follow_page_mask() * pin. We cannot do it under lru_lock however. If it's * the last pin, __page_cache_release() would deadlock. */ +putback: + spin_unlock_irq(&zone->zone_pgdat->lru_lock); pagevec_add(&pvec_putback, pvec->pages[i]); pvec->pages[i] = NULL; } + /* tempary disable irq, will remove later */ + local_irq_disable(); __mod_zone_page_state(zone, NR_MLOCK, delta_munlocked); - spin_unlock_irq(&zone->zone_pgdat->lru_lock); + local_irq_enable(); /* Now we can release pins of pages that we are not munlocking */ pagevec_release(&pvec_putback); -- 1.8.3.1