From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753771AbbCaIx3 (ORCPT ); Tue, 31 Mar 2015 04:53:29 -0400 Received: from TYO201.gate.nec.co.jp ([210.143.35.51]:49700 "EHLO tyo201.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753598AbbCaIxQ convert rfc822-to-8bit (ORCPT ); Tue, 31 Mar 2015 04:53:16 -0400 From: Naoya Horiguchi To: Andrew Morton CC: Hugh Dickins , Michal Hocko , Mel Gorman , Johannes Weiner , David Rientjes , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "Naoya Horiguchi" Subject: [PATCH v3 1/3] mm: don't call __page_cache_release for hugetlb Thread-Topic: [PATCH v3 1/3] mm: don't call __page_cache_release for hugetlb Thread-Index: AQHQa4/GrKyW959y1Eme18q52NOEFg== Date: Tue, 31 Mar 2015 08:50:45 +0000 Message-ID: <1427791840-11247-2-git-send-email-n-horiguchi@ah.jp.nec.com> References: <1427791840-11247-1-git-send-email-n-horiguchi@ah.jp.nec.com> In-Reply-To: <1427791840-11247-1-git-send-email-n-horiguchi@ah.jp.nec.com> Accept-Language: ja-JP, en-US Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.128.101.30] Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org __put_compound_page() calls __page_cache_release() to do some freeing works, but it's obviously for thps, not for hugetlb. We didn't care it because PageLRU is always cleared and page->mem_cgroup is always NULL for hugetlb. But it's not correct and has potential risks, so let's make it conditional. Signed-off-by: Naoya Horiguchi --- mm/swap.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git v4.0-rc6.orig/mm/swap.c v4.0-rc6/mm/swap.c index cd3a5e64cea9..8e46823c3319 100644 --- v4.0-rc6.orig/mm/swap.c +++ v4.0-rc6/mm/swap.c @@ -31,6 +31,7 @@ #include #include #include +#include #include "internal.h" @@ -75,7 +76,14 @@ static void __put_compound_page(struct page *page) { compound_page_dtor *dtor; - __page_cache_release(page); + /* + * __page_cache_release() is supposed to be called for thp, not for + * hugetlb. This is because hugetlb page does never have PageLRU set + * (it's never listed to any LRU lists) and no memcg routines should + * be called for hugetlb (it has a separate hugetlb_cgroup.) + */ + if (!PageHuge(page)) + __page_cache_release(page); dtor = get_compound_page_dtor(page); (*dtor)(page); } -- 1.9.3