From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C1093C433E9 for ; Thu, 4 Mar 2021 07:44:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8B6D864F04 for ; Thu, 4 Mar 2021 07:44:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234183AbhCDHoC (ORCPT ); Thu, 4 Mar 2021 02:44:02 -0500 Received: from szxga06-in.huawei.com ([45.249.212.32]:13430 "EHLO szxga06-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233627AbhCDHng (ORCPT ); Thu, 4 Mar 2021 02:43:36 -0500 Received: from DGGEMS412-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4DrjVM2BJyzjV7R; Thu, 4 Mar 2021 15:41:31 +0800 (CST) Received: from huawei.com (10.175.112.208) by DGGEMS412-HUB.china.huawei.com (10.3.19.212) with Microsoft SMTP Server id 14.3.498.0; Thu, 4 Mar 2021 15:42:44 +0800 From: Zhou Guanghui To: , CC: , , , , , , , , , , , Subject: [PATCH v2 2/2] mm/memcg: set memcg when split page Date: Thu, 4 Mar 2021 07:40:53 +0000 Message-ID: <20210304074053.65527-3-zhouguanghui1@huawei.com> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20210304074053.65527-1-zhouguanghui1@huawei.com> References: <20210304074053.65527-1-zhouguanghui1@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.112.208] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As described in the split_page function comment, for the non-compound high order page, the sub-pages must be freed individually. If the memcg of the fisrt page is valid, the tail pages cannot be uncharged when be freed. For example, when alloc_pages_exact is used to allocate 1MB continuous physical memory, 2MB is charged(kmemcg is enabled and __GFP_ACCOUNT is set). When make_alloc_exact free the unused 1MB and free_pages_exact free the applied 1MB, actually, only 4KB(one page) is uncharged. Therefore, the memcg of the tail page needs to be set when split page. Signed-off-by: Zhou Guanghui --- mm/page_alloc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 3e4b29ee2b1e..3ed783e25c3c 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3310,6 +3310,7 @@ void split_page(struct page *page, unsigned int order) for (i = 1; i < (1 << order); i++) set_page_refcounted(page + i); split_page_owner(page, 1 << order); + split_page_memcg(page, 1 << order); } EXPORT_SYMBOL_GPL(split_page); -- 2.25.0