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=unavailable 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 85D52C432BE for ; Mon, 16 Aug 2021 07:13:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2C63E6023E for ; Mon, 16 Aug 2021 07:13:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 2C63E6023E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id A8AB28D0007; Mon, 16 Aug 2021 03:12:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A3B378D0006; Mon, 16 Aug 2021 03:12:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9021F8D0007; Mon, 16 Aug 2021 03:12:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0128.hostedemail.com [216.40.44.128]) by kanga.kvack.org (Postfix) with ESMTP id 6BD598D0006 for ; Mon, 16 Aug 2021 03:12:52 -0400 (EDT) Received: from smtpin34.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 1B8AC1F363 for ; Mon, 16 Aug 2021 07:12:52 +0000 (UTC) X-FDA: 78480076584.34.AF23CDC Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by imf12.hostedemail.com (Postfix) with ESMTP id 5B840100150A for ; Mon, 16 Aug 2021 07:12:51 +0000 (UTC) Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Gp4yn2xmzzdbLZ; Mon, 16 Aug 2021 15:09:05 +0800 (CST) Received: from dggema756-chm.china.huawei.com (10.1.198.198) by dggemv711-chm.china.huawei.com (10.1.198.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2176.2; Mon, 16 Aug 2021 15:12:46 +0800 Received: from localhost.localdomain (10.175.112.125) by dggema756-chm.china.huawei.com (10.1.198.198) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Mon, 16 Aug 2021 15:12:46 +0800 From: Chen Huang To: Roman Gushchin , Muchun Song , "Wang Hai" , Greg Kroah-Hartman CC: , , , Chen Huang , Andrew Morton , Alexei Starovoitov Subject: [PATCH 5.10.y 03/11] mm: Introduce page memcg flags Date: Mon, 16 Aug 2021 07:21:39 +0000 Message-ID: <20210816072147.3481782-4-chenhuang5@huawei.com> X-Mailer: git-send-email 2.18.0.huawei.25 In-Reply-To: <20210816072147.3481782-1-chenhuang5@huawei.com> References: <20210816072147.3481782-1-chenhuang5@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggema756-chm.china.huawei.com (10.1.198.198) X-CFilter-Loop: Reflected X-Rspamd-Queue-Id: 5B840100150A Authentication-Results: imf12.hostedemail.com; dkim=none; spf=pass (imf12.hostedemail.com: domain of chenhuang5@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=chenhuang5@huawei.com; dmarc=pass (policy=none) header.from=huawei.com X-Rspamd-Server: rspam01 X-Stat-Signature: n3tqs6czt7qd4j7z4q1bsn8yomsm4gsw X-HE-Tag: 1629097971-983853 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Roman Gushchin The lowest bit in page->memcg_data is used to distinguish between struct memory_cgroup pointer and a pointer to a objcgs array. All checks and modifications of this bit are open-coded. Let's formalize it using page memcg flags, defined in enum page_memcg_data_flags. Additional flags might be added later. Signed-off-by: Roman Gushchin Signed-off-by: Andrew Morton Signed-off-by: Alexei Starovoitov Reviewed-by: Shakeel Butt Acked-by: Johannes Weiner Acked-by: Michal Hocko Link: https://lkml.kernel.org/r/20201027001657.3398190-4-guro@fb.com Link: https://lore.kernel.org/bpf/20201201215900.3569844-4-guro@fb.com Signed-off-by: Chen Huang --- include/linux/memcontrol.h | 32 ++++++++++++++++++++------------ 1 file changed, 20 insertions(+), 12 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 2805fe81f97d..4a0feb9d4b82 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -343,6 +343,15 @@ struct mem_cgroup { extern struct mem_cgroup *root_mem_cgroup; +enum page_memcg_data_flags { + /* page->memcg_data is a pointer to an objcgs vector */ + MEMCG_DATA_OBJCGS = (1UL << 0), + /* the next bit after the last actual flag */ + __NR_MEMCG_DATA_FLAGS = (1UL << 1), +}; + +#define MEMCG_DATA_FLAGS_MASK (__NR_MEMCG_DATA_FLAGS - 1) + /* * page_memcg - get the memory cgroup associated with a page * @page: a pointer to the page struct @@ -404,13 +413,7 @@ static inline struct mem_cgroup *page_memcg_check(struct page *page) */ unsigned long memcg_data = READ_ONCE(page->memcg_data); - /* - * The lowest bit set means that memcg isn't a valid - * memcg pointer, but a obj_cgroups pointer. - * In this case the page is shared and doesn't belong - * to any specific memory cgroup. - */ - if (memcg_data & 0x1UL) + if (memcg_data & MEMCG_DATA_OBJCGS) return NULL; return (struct mem_cgroup *)memcg_data; @@ -429,7 +432,11 @@ static inline struct mem_cgroup *page_memcg_check(struct page *page) */ static inline struct obj_cgroup **page_objcgs(struct page *page) { - return (struct obj_cgroup **)(READ_ONCE(page->memcg_data) & ~0x1UL); + unsigned long memcg_data = READ_ONCE(page->memcg_data); + + VM_BUG_ON_PAGE(memcg_data && !(memcg_data & MEMCG_DATA_OBJCGS), page); + + return (struct obj_cgroup **)(memcg_data & ~MEMCG_DATA_FLAGS_MASK); } /* @@ -444,10 +451,10 @@ static inline struct obj_cgroup **page_objcgs_check(struct page *page) { unsigned long memcg_data = READ_ONCE(page->memcg_data); - if (memcg_data && (memcg_data & 0x1UL)) - return (struct obj_cgroup **)(memcg_data & ~0x1UL); + if (!memcg_data || !(memcg_data & MEMCG_DATA_OBJCGS)) + return NULL; - return NULL; + return (struct obj_cgroup **)(memcg_data & ~MEMCG_DATA_FLAGS_MASK); } /* @@ -460,7 +467,8 @@ static inline struct obj_cgroup **page_objcgs_check(struct page *page) static inline bool set_page_objcgs(struct page *page, struct obj_cgroup **objcgs) { - return !cmpxchg(&page->memcg_data, 0, (unsigned long)objcgs | 0x1UL); + return !cmpxchg(&page->memcg_data, 0, (unsigned long)objcgs | + MEMCG_DATA_OBJCGS); } #else static inline struct obj_cgroup **page_objcgs(struct page *page) -- 2.18.0.huawei.25