From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Shi Subject: [PATCH v9 09/20] mm/mlock: ClearPageLRU before get lru lock in munlock page isolation Date: Mon, 2 Mar 2020 19:00:19 +0800 Message-ID: <1583146830-169516-10-git-send-email-alex.shi@linux.alibaba.com> References: <1583146830-169516-1-git-send-email-alex.shi@linux.alibaba.com> Return-path: In-Reply-To: <1583146830-169516-1-git-send-email-alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, mgorman-3eNAlZScCAx27rWaFMvyedHuzzzSOjJt@public.gmane.org, tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, khlebnikov-XoJtRXgx1JseBXzfvpsJ4g@public.gmane.org, daniel.m.jordan-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, yang.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org, willy-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org, lkp-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org Cc: Alex Shi , "Kirill A. Shutemov" , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org This is one of effort to split the PageLRU clear from old page isolation. This patch move the lru_lock after TestClearPageLRU, which takes holding PageLRU as precondition for page isolation, as a preparation for later lru_lock replacment. So we have to unfold __munlock_isolate_lru_page. __split_huge_page_refcount doesn't exist, but we still have to guard PageMlocked in __split_huge_page_tail. That make code ugly. Anyway we still remove 2 gotos. [lkp-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org: found a sleeping function bug ... at mm/rmap.c:1861] Signed-off-by: Alex Shi Cc: Kirill A. Shutemov Cc: Andrew Morton Cc: Johannes Weiner Cc: Matthew Wilcox Cc: Hugh Dickins Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org --- mm/mlock.c | 35 +++++++++++++++++++++++------------ 1 file changed, 23 insertions(+), 12 deletions(-) diff --git a/mm/mlock.c b/mm/mlock.c index 03b3a5d99ad7..7ddc52ca14b1 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -181,6 +181,7 @@ 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 +190,42 @@ 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); + clearlru = TestClearPageLRU(page); 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; + 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; } @@ -323,8 +334,8 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone) pagevec_add(&pvec_putback, pvec->pages[i]); pvec->pages[i] = NULL; } - __mod_zone_page_state(zone, NR_MLOCK, delta_munlocked); spin_unlock_irq(&zone->zone_pgdat->lru_lock); + __mod_zone_page_state(zone, NR_MLOCK, delta_munlocked); /* Now we can release pins of pages that we are not munlocking */ pagevec_release(&pvec_putback); -- 1.8.3.1