Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751949AbaKFWk3 (ORCPT ); Thu, 6 Nov 2014 17:40:29 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:58639 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752276AbaKFWkV (ORCPT ); Thu, 6 Nov 2014 17:40:21 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Yu Zhao , Andrea Arcangeli , Mel Gorman , David Rientjes , Bob Liu , Andrew Morton , Linus Torvalds , Kamal Mostafa Subject: [PATCH 3.13 149/162] mm: free compound page with correct order Date: Thu, 6 Nov 2014 14:36:53 -0800 Message-Id: <1415313426-9622-150-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1415313426-9622-1-git-send-email-kamal@canonical.com> References: <1415313426-9622-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11.11 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Yu Zhao commit 5ddacbe92b806cd5b4f8f154e8e46ac267fff55c upstream. Compound page should be freed by put_page() or free_pages() with correct order. Not doing so will cause tail pages leaked. The compound order can be obtained by compound_order() or use HPAGE_PMD_ORDER in our case. Some people would argue the latter is faster but I prefer the former which is more general. This bug was observed not just on our servers (the worst case we saw is 11G leaked on a 48G machine) but also on our workstations running Ubuntu based distro. $ cat /proc/vmstat | grep thp_zero_page_alloc thp_zero_page_alloc 55 thp_zero_page_alloc_failed 0 This means there is (thp_zero_page_alloc - 1) * (2M - 4K) memory leaked. Fixes: 97ae17497e99 ("thp: implement refcounting for huge zero page") Signed-off-by: Yu Zhao Acked-by: Kirill A. Shutemov Cc: Andrea Arcangeli Cc: Mel Gorman Cc: David Rientjes Cc: Bob Liu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Kamal Mostafa --- mm/huge_memory.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 64a7f9c..310f27e 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -193,7 +193,7 @@ retry: preempt_disable(); if (cmpxchg(&huge_zero_page, NULL, zero_page)) { preempt_enable(); - __free_page(zero_page); + __free_pages(zero_page, compound_order(zero_page)); goto retry; } @@ -225,7 +225,7 @@ static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { struct page *zero_page = xchg(&huge_zero_page, NULL); BUG_ON(zero_page == NULL); - __free_page(zero_page); + __free_pages(zero_page, compound_order(zero_page)); return HPAGE_PMD_NR; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/