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=-14.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 858C8C2D0E2 for ; Tue, 22 Sep 2020 20:57:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 27E392376F for ; Tue, 22 Sep 2020 20:57:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="ZAHx4psj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726710AbgIVU47 (ORCPT ); Tue, 22 Sep 2020 16:56:59 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:9168 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726448AbgIVU46 (ORCPT ); Tue, 22 Sep 2020 16:56:58 -0400 X-Greylist: delayed 1171 seconds by postgrey-1.27 at vger.kernel.org; Tue, 22 Sep 2020 16:56:57 EDT Received: from pps.filterd (m0089730.ppops.net [127.0.0.1]) by m0089730.ppops.net (8.16.0.42/8.16.0.42) with SMTP id 08MKYnAV016666 for ; Tue, 22 Sep 2020 13:37:31 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=TypEATBWbpt53XcoP91sJwuxbGktC5GF4Gd45XiUxGA=; b=ZAHx4psjUHQKUy08Ja3T8bZ41pABf78i5/TqDw2OCMQlmFntdsRfYLYEODY4IQ1gCLgT pIN70pvgpHqOg3kzjH4PwnjeMYJIG7H32hmYkyTwHu0Nc4WkSb8CuZInylXSR7CP0lt0 Sx6GexiL5wFlk/6RO9g5gUC7y/eeHp6tcOM= Received: from mail.thefacebook.com ([163.114.132.120]) by m0089730.ppops.net with ESMTP id 33qn0as92p-17 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 22 Sep 2020 13:37:31 -0700 Received: from intmgw001.41.prn1.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:11d::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Tue, 22 Sep 2020 13:37:25 -0700 Received: by devvm1755.vll0.facebook.com (Postfix, from userid 111017) id DE5AF864B60; Tue, 22 Sep 2020 13:37:21 -0700 (PDT) From: Roman Gushchin To: Andrew Morton CC: Shakeel Butt , Johannes Weiner , Michal Hocko , , , , Roman Gushchin Subject: [PATCH v1 4/4] mm: convert page kmemcg type to a page memcg flag Date: Tue, 22 Sep 2020 13:37:00 -0700 Message-ID: <20200922203700.2879671-5-guro@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200922203700.2879671-1-guro@fb.com> References: <20200922203700.2879671-1-guro@fb.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-09-22_18:2020-09-21,2020-09-22 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 phishscore=0 adultscore=0 bulkscore=0 lowpriorityscore=0 malwarescore=0 suspectscore=2 mlxscore=0 mlxlogscore=916 clxscore=1015 priorityscore=1501 impostorscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009220161 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org PageKmemcg flag is currently defined as a page type (like buddy, offline, table and guard). Semantically it means that the page was accounted as a kernel memory by the page allocator and has to be uncharged on the release. As a side effect of defining the flag as a page type, the accounted page can't be mapped to userspace (look at page_has_type() and comments above). In particular, this blocks the accounting of vmalloc-backed memory used by some bpf maps, because these maps do map the memory to userspace. One option is to fix it by complicating the access to page->mapcount, which provides some free bits for page->page_type. But it's way better to move this flag into page->memcg_data flags. Indeed, the flag makes no sense without enabled memory cgroups and memory cgroup pointer set in particular. This commit replaces PageKmemcg() and __SetPageKmemcg() with PageMemcgKmem() and SetPageMemcgKmem(). __ClearPageKmemcg() can be simple deleted because clear_page_mem_cgroup() already does the job. As a bonus, on !CONFIG_MEMCG build the PageMemcgKmem() check will be compiled out. Signed-off-by: Roman Gushchin --- include/linux/memcontrol.h | 58 ++++++++++++++++++++++++++++++++++++-- include/linux/page-flags.h | 11 ++------ mm/memcontrol.c | 14 +++------ mm/page_alloc.c | 2 +- 4 files changed, 62 insertions(+), 23 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 9a49f1e1c0c7..390db58500d5 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -346,8 +346,14 @@ extern struct mem_cgroup *root_mem_cgroup; enum page_memcg_flags { /* page->memcg_data is a pointer to an objcgs vector */ PG_MEMCG_OBJ_CGROUPS, + /* page has been accounted as a non-slab kernel page */ + PG_MEMCG_KMEM, + /* the next bit after the last actual flag */ + PG_MEMCG_LAST_FLAG, }; =20 +#define MEMCG_FLAGS_MASK ((1UL << PG_MEMCG_LAST_FLAG) - 1) + /* * page_mem_cgroup - get the memory cgroup associated with a page * @page: a pointer to the page struct @@ -359,8 +365,12 @@ enum page_memcg_flags { */ static inline struct mem_cgroup *page_mem_cgroup(struct page *page) { + unsigned long memcg_data =3D page->memcg_data; + VM_BUG_ON_PAGE(PageSlab(page), page); - return (struct mem_cgroup *)page->memcg_data; + VM_BUG_ON_PAGE(test_bit(PG_MEMCG_OBJ_CGROUPS, &memcg_data), page); + + return (struct mem_cgroup *)(memcg_data & ~MEMCG_FLAGS_MASK); } =20 /* @@ -379,7 +389,7 @@ static inline struct mem_cgroup *page_mem_cgroup_chec= k(struct page *page) if (test_bit(PG_MEMCG_OBJ_CGROUPS, &memcg_data)) return NULL; =20 - return (struct mem_cgroup *)memcg_data; + return (struct mem_cgroup *)(memcg_data & ~MEMCG_FLAGS_MASK); } =20 /* @@ -408,6 +418,36 @@ static inline void clear_page_mem_cgroup(struct page= *page) page->memcg_data =3D 0; } =20 +/* + * PageMemcgKmem - check if the page has MemcgKmem flag set + * @page: a pointer to the page struct + * + * Checks if the page has MemcgKmem flag set. The caller must ensure tha= t + * the page has an associated memory cgroup. It's not safe to call this = function + * against some types of pages, e.g. slab pages. + */ +static inline bool PageMemcgKmem(struct page *page) +{ + VM_BUG_ON_PAGE(test_bit(PG_MEMCG_OBJ_CGROUPS, &page->memcg_data), page)= ; + return test_bit(PG_MEMCG_KMEM, &page->memcg_data); +} + +/* + * SetPageMemcgKmem - set the page's MemcgKmem flag + * @page: a pointer to the page struct + * + * Set the page's MemcgKmem flag. The caller must ensure that the page h= as + * an associated memory cgroup. It's not safe to call this function + * against some types of pages, e.g. slab pages. + */ +static inline void SetPageMemcgKmem(struct page *page) +{ + VM_BUG_ON_PAGE(!page->memcg_data, page); + VM_BUG_ON_PAGE(test_bit(PG_MEMCG_OBJ_CGROUPS, &page->memcg_data), page)= ; + __set_bit(PG_MEMCG_KMEM, &page->memcg_data); +} + + #ifdef CONFIG_MEMCG_KMEM /* * page_obj_cgroups - get the object cgroups vector associated with a pa= ge @@ -426,6 +466,7 @@ static inline struct obj_cgroup **page_obj_cgroups(st= ruct page *page) VM_BUG_ON_PAGE(memcg_data && !test_bit(PG_MEMCG_OBJ_CGROUPS, &memcg_data), page); __clear_bit(PG_MEMCG_OBJ_CGROUPS, &memcg_data); + VM_BUG_ON_PAGE(test_bit(PG_MEMCG_KMEM, &memcg_data), page); =20 return (struct obj_cgroup **)memcg_data; } @@ -442,8 +483,10 @@ static inline struct obj_cgroup **page_obj_cgroups_c= heck(struct page *page) { unsigned long memcg_data =3D page->memcg_data; =20 - if (memcg_data && test_bit(PG_MEMCG_OBJ_CGROUPS, &memcg_data)) + if (memcg_data && test_bit(PG_MEMCG_OBJ_CGROUPS, &memcg_data)) { + VM_BUG_ON_PAGE(test_bit(PG_MEMCG_KMEM, &memcg_data), page); return (struct obj_cgroup **)memcg_data; + } =20 return NULL; } @@ -1115,6 +1158,15 @@ static inline void clear_page_mem_cgroup(struct pa= ge *page) { } =20 +static inline bool PageMemcgKmem(struct page *page) +{ + return false; +} + +static inline void SetPageMemcgKmem(struct page *page) +{ +} + static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg) { return true; diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index fbbb841a9346..a7ca01ae78d9 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -712,9 +712,8 @@ PAGEFLAG_FALSE(DoubleMap) #define PAGE_MAPCOUNT_RESERVE -128 #define PG_buddy 0x00000080 #define PG_offline 0x00000100 -#define PG_kmemcg 0x00000200 -#define PG_table 0x00000400 -#define PG_guard 0x00000800 +#define PG_table 0x00000200 +#define PG_guard 0x00000400 =20 #define PageType(page, flag) \ ((page->page_type & (PAGE_TYPE_BASE | flag)) =3D=3D PAGE_TYPE_BASE) @@ -765,12 +764,6 @@ PAGE_TYPE_OPS(Buddy, buddy) */ PAGE_TYPE_OPS(Offline, offline) =20 -/* - * If kmemcg is enabled, the buddy allocator will set PageKmemcg() on - * pages allocated with __GFP_ACCOUNT. It gets cleared on page free. - */ -PAGE_TYPE_OPS(Kmemcg, kmemcg) - /* * Marks pages in use as page tables. */ diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 69e3dbb3d2cf..1d22fa4c4a88 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3081,7 +3081,7 @@ int __memcg_kmem_charge_page(struct page *page, gfp= _t gfp, int order) ret =3D __memcg_kmem_charge(memcg, gfp, 1 << order); if (!ret) { set_page_mem_cgroup(page, memcg); - __SetPageKmemcg(page); + SetPageMemcgKmem(page); return 0; } css_put(&memcg->css); @@ -3106,10 +3106,6 @@ void __memcg_kmem_uncharge_page(struct page *page,= int order) __memcg_kmem_uncharge(memcg, nr_pages); clear_page_mem_cgroup(page); css_put(&memcg->css); - - /* slab pages do not have PageKmemcg flag set */ - if (PageKmemcg(page)) - __ClearPageKmemcg(page); } =20 static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_= bytes) @@ -6890,12 +6886,10 @@ static void uncharge_page(struct page *page, stru= ct uncharge_gather *ug) nr_pages =3D compound_nr(page); ug->nr_pages +=3D nr_pages; =20 - if (!PageKmemcg(page)) { - ug->pgpgout++; - } else { + if (PageMemcgKmem(page)) ug->nr_kmem +=3D nr_pages; - __ClearPageKmemcg(page); - } + else + ug->pgpgout++; =20 ug->dummy_page =3D page; clear_page_mem_cgroup(page); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d4d181e15e7c..6807e37d78ba 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1197,7 +1197,7 @@ static __always_inline bool free_pages_prepare(stru= ct page *page, } if (PageMappingFlags(page)) page->mapping =3D NULL; - if (memcg_kmem_enabled() && PageKmemcg(page)) + if (memcg_kmem_enabled() && PageMemcgKmem(page)) __memcg_kmem_uncharge_page(page, order); if (check_free) bad +=3D check_free_page(page); --=20 2.26.2