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,DKIM_INVALID, DKIM_SIGNED,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,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 47B66C433B4 for ; Tue, 20 Apr 2021 13:17:17 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CA1E860BD3 for ; Tue, 20 Apr 2021 13:17:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CA1E860BD3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 22F6E6B006C; Tue, 20 Apr 2021 09:17:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 205A26B0073; Tue, 20 Apr 2021 09:17:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 080A46B0075; Tue, 20 Apr 2021 09:17:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0095.hostedemail.com [216.40.44.95]) by kanga.kvack.org (Postfix) with ESMTP id E0C796B0073 for ; Tue, 20 Apr 2021 09:17:15 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 93E17180AD82F for ; Tue, 20 Apr 2021 13:17:15 +0000 (UTC) X-FDA: 78052796430.30.A45F9DF Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf25.hostedemail.com (Postfix) with ESMTP id 139EE6000132 for ; Tue, 20 Apr 2021 13:17:11 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id CE057613CA; Tue, 20 Apr 2021 13:17:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1618924634; bh=I/WWp3ZhiKpLexAP/6uikhopmlNfpvxqz9r1ZOciMHE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UjXkKne+FA6PkCeeaRcCEbX6RLKVRuOZ950ZCFbmq7MKlDrFMoTQh9mnZRkPy2aGx /gLjaLVwUrA1Rp2N6jWx+BpEIWTFmBe1vqlBsoiPGg0GkiVz5tLIB0gsurVKD4pkaw 7gXvNEn04SUiRgGDfrhEgpO4bnMBzvJNM0M7y6t+/VENHx8C/E9ulvt5AmJqWDUUQn zKcjUrgm6zeqJrE/wb8pbdExYJ3d26l9AX4v5MOq3N/1HlIm+936DGGRA0IZdnoFfM VLSUXFbe7czTs8sXSG+NXGS+jKF3NMjIzssHmIppiVUWTlLNzvGw0BLAO7qZijhlnW CdBL8LeCbxZ3w== From: Mike Rapoport To: Andrew Morton Cc: Alexander Viro , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Christopher Lameter , Dan Williams , Dave Hansen , David Hildenbrand , Elena Reshetova , "H. Peter Anvin" , Ingo Molnar , James Bottomley , "Kirill A. Shutemov" , Matthew Wilcox , Matthew Garrett , Mark Rutland , Michal Hocko , Mike Rapoport , Mike Rapoport , Michael Kerrisk , Palmer Dabbelt , Paul Walmsley , Peter Zijlstra , "Rafael J. Wysocki" , Rick Edgecombe , Roman Gushchin , Shakeel Butt , Shuah Khan , Thomas Gleixner , Tycho Andersen , Will Deacon , Yury Norov , linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-nvdimm@lists.01.org, linux-riscv@lists.infradead.org, x86@kernel.org, kernel test robot Subject: [PATCH v2 2/2] secretmem: optimize page_is_secretmem() Date: Tue, 20 Apr 2021 16:16:11 +0300 Message-Id: <20210420131611.8259-5-rppt@kernel.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20210420131611.8259-1-rppt@kernel.org> References: <20210420131611.8259-1-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Rspamd-Queue-Id: 139EE6000132 X-Stat-Signature: 1bun9douguyksoafnhdiwsp16ue4i9g5 X-Rspamd-Server: rspam02 Received-SPF: none (kernel.org>: No applicable sender policy available) receiver=imf25; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1618924631-399135 Content-Transfer-Encoding: quoted-printable 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: Mike Rapoport Kernel test robot reported -4.2% regression of will-it-scale.per_thread_o= ps due to commit "mm: introduce memfd_secret system call to create "secret" memory areas". The perf profile of the test indicated that the regression is caused by page_is_secretmem() called from gup_pte_range() (inlined by gup_pgd_range= ): 27.76 +2.5 30.23 perf-profile.children.cycles-pp.gup_pgd_range 0.00 +3.2 3.19 =C2=B1 2% perf-profile.children.cycles-pp.page_mappi= ng 0.00 +3.7 3.66 =C2=B1 2% perf-profile.children.cycles-pp.page_is_se= cretmem Further analysis showed that the slow down happens because neither page_is_secretmem() nor page_mapping() are not inline and moreover, multiple page flags checks in page_mapping() involve calling compound_head() several times for the same page. Make page_is_secretmem() inline and replace page_mapping() with page flag checks that do not imply page-to-head conversion. Reported-by: kernel test robot Signed-off-by: Mike Rapoport --- include/linux/secretmem.h | 26 +++++++++++++++++++++++++- mm/secretmem.c | 12 +----------- 2 files changed, 26 insertions(+), 12 deletions(-) diff --git a/include/linux/secretmem.h b/include/linux/secretmem.h index 907a6734059c..b842b38cbeb1 100644 --- a/include/linux/secretmem.h +++ b/include/linux/secretmem.h @@ -4,8 +4,32 @@ =20 #ifdef CONFIG_SECRETMEM =20 +extern const struct address_space_operations secretmem_aops; + +static inline bool page_is_secretmem(struct page *page) +{ + struct address_space *mapping; + + /* + * Using page_mapping() is quite slow because of the actual call + * instruction and repeated compound_head(page) inside the + * page_mapping() function. + * We know that secretmem pages are not compound and LRU so we can + * save a couple of cycles here. + */ + if (PageCompound(page) || !PageLRU(page)) + return false; + + mapping =3D (struct address_space *) + ((unsigned long)page->mapping & ~PAGE_MAPPING_FLAGS); + + if (mapping !=3D page->mapping) + return false; + + return page->mapping->a_ops =3D=3D &secretmem_aops; +} + bool vma_is_secretmem(struct vm_area_struct *vma); -bool page_is_secretmem(struct page *page); bool secretmem_active(void); =20 #else diff --git a/mm/secretmem.c b/mm/secretmem.c index 3b1ba3991964..0bcd15e1b549 100644 --- a/mm/secretmem.c +++ b/mm/secretmem.c @@ -151,22 +151,12 @@ static void secretmem_freepage(struct page *page) clear_highpage(page); } =20 -static const struct address_space_operations secretmem_aops =3D { +const struct address_space_operations secretmem_aops =3D { .freepage =3D secretmem_freepage, .migratepage =3D secretmem_migratepage, .isolate_page =3D secretmem_isolate_page, }; =20 -bool page_is_secretmem(struct page *page) -{ - struct address_space *mapping =3D page_mapping(page); - - if (!mapping) - return false; - - return mapping->a_ops =3D=3D &secretmem_aops; -} - static struct vfsmount *secretmem_mnt; =20 static struct file *secretmem_file_create(unsigned long flags) --=20 2.28.0