From patchwork Thu Mar 2 23:27:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Chamberlain X-Patchwork-Id: 63659 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:5915:0:0:0:0:0 with SMTP id v21csp127233wrd; Thu, 2 Mar 2023 15:45:28 -0800 (PST) X-Google-Smtp-Source: AK7set/pH1Lbyo6pO2nh6q6JKvpSCdCkgX9vHqaTiXsnFjsJOnEVcPWUZzVIXCVeX95L3x2Evvdc X-Received: by 2002:a05:6a20:4a1d:b0:cb:9bd0:7ee2 with SMTP id fr29-20020a056a204a1d00b000cb9bd07ee2mr132602pzb.45.1677800728650; Thu, 02 Mar 2023 15:45:28 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1677800728; cv=none; d=google.com; s=arc-20160816; b=Otdg7Nm1pgxndZcP05/bS3v2ScEShspkLb6sGLrs1BzscD+/BW7ew3GL6hn1o35DVi 5qlVFWAc/hCfnYaMdVqff1IzNH1dXLcRpzT54JzdfgrMjCAQvq9QTWeBx1E82LMAYzim 4udqoML5tzMvAGF9DcILpWBYMlTnqf8wuEWQ3sftcMTJrjTzSAYKNPNaFrZQd2P4z+/8 t/Gb5is8zL8Xj65GQ/LoZMz3NHTE+tZvDZSTjppkpU0Z6UPI6shf6WlNo83XlRmpX3Ue /wke8BEx1dQBQPsS8+bqbEMn2i6D38LJrQlpJtUhLSutOi3QzU/S7NwQevSlh83jmo34 Q2Ig== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=X3niQqWSDaRdijh0GPlKHY1yoysmmoQVBPzADYFTAAk=; b=isMNhKziaLTjgdg/r5kWmJrAMO5OS3R9WadXcK8UkUwE3MaX4fbhJ8W52H8ydjTxB0 Yu7ZBwdFyxK3yah4R0xsgI7zIoVamcXDfH8I3eeMxI4p5a56/BGzED4vNGWF24yTkwcT +hgMPXvpk0DNFXp36DlIleNJ0+Jnn9rQ0Uy7ixTZBVOX9sdOBT78UP+KNp52nCUhM7mI 4a8rnC2DjRJNgwGtBoEOsnFH9P5rOyR/tw0NuSUykzLdsdqAza7qp+0l8zwGSUJWD5gK pU8uTGqEK2sHVXJYz4HqGQWWrBoYDzYcWX5fIwIW84Dzf2MlUDY41tblzSDFGLvFOvqQ PuyQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b="A1T9i9l/"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id w4-20020a656944000000b00503a0139e29si481291pgq.688.2023.03.02.15.45.14; Thu, 02 Mar 2023 15:45:28 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b="A1T9i9l/"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229983AbjCBX2Q (ORCPT + 99 others); Thu, 2 Mar 2023 18:28:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45104 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229728AbjCBX2L (ORCPT ); Thu, 2 Mar 2023 18:28:11 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 458872693 for ; Thu, 2 Mar 2023 15:28:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=X3niQqWSDaRdijh0GPlKHY1yoysmmoQVBPzADYFTAAk=; b=A1T9i9l/KhB0qQZfQ43uw6v8kl DTCTRWDp8ClUN+kK4tmCnmWxFQZNAu7/KlswhmxIBSNnubcoAF/0v32hcIh7vsx/2fYebdrGuOFfD cAnCJAhSbnS1joVOILJsNws5NnKu+5mYSq1Eg2EeWdf/r2/gWG/2PiHtkicrXr4nv4g8KNvqyd+h5 zSb4BZm/8ekQ3nBFaKCQSpzvzbNAJor5LMWh0xvyjEChMKRIwSW6QtvSbE5HH6mk+eiwxMNN1wRYL NN7yYd8Xgu8+6Yqm6vtCggq8UsMK7X8LuLapwpCc3bG7p2c7yZG4p+iTMZohqzaupylW/idKcbw0L a/8QUp7w==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pXsL9-003j3I-3W; Thu, 02 Mar 2023 23:27:59 +0000 From: Luis Chamberlain To: hughd@google.com, akpm@linux-foundation.org, willy@infradead.org, brauner@kernel.org Cc: linux-mm@kvack.org, p.raghav@samsung.com, da.gomez@samsung.com, a.manzanares@samsung.com, dave@stgolabs.net, yosryahmed@google.com, keescook@chromium.org, mcgrof@kernel.org, patches@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 1/6] shmem: remove check for folio lock on writepage() Date: Thu, 2 Mar 2023 15:27:53 -0800 Message-Id: <20230302232758.888157-2-mcgrof@kernel.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20230302232758.888157-1-mcgrof@kernel.org> References: <20230302232758.888157-1-mcgrof@kernel.org> MIME-Version: 1.0 Sender: Luis Chamberlain X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1759301577121824006?= X-GMAIL-MSGID: =?utf-8?q?1759301577121824006?= Matthew notes we should not need to check the folio lock on the writepage() callback so remove it. This sanity check has been lingering since linux-history days. We remove this as we tidy up the writepage() callback to make things a bit clearer. Suggested-by: Matthew Wilcox Signed-off-by: Luis Chamberlain Acked-by: David Hildenbrand --- mm/shmem.c | 1 - 1 file changed, 1 deletion(-) diff --git a/mm/shmem.c b/mm/shmem.c index 1af85259b6fc..7fff1a3af092 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1354,7 +1354,6 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) folio_clear_dirty(folio); } - BUG_ON(!folio_test_locked(folio)); mapping = folio->mapping; index = folio->index; inode = mapping->host; From patchwork Thu Mar 2 23:27:54 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Chamberlain X-Patchwork-Id: 63661 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:5915:0:0:0:0:0 with SMTP id v21csp127814wrd; Thu, 2 Mar 2023 15:47:18 -0800 (PST) X-Google-Smtp-Source: AK7set+mqhGF+OZPDJVZGxwA08tlcQqJqsUN8i1qs2gCy32yWp3kk//fcZUYXaWqZEbedMdVLh9N X-Received: by 2002:a05:6a20:144c:b0:cd:272:fd3f with SMTP id a12-20020a056a20144c00b000cd0272fd3fmr243334pzi.25.1677800838544; Thu, 02 Mar 2023 15:47:18 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1677800838; cv=none; d=google.com; s=arc-20160816; b=N/PTOi4YDFObsgNPwsBMZtWmdSf1mOWBpQw/g3tSxZ0Hd4v8kHhIQqHKqB8rdVAuG6 qI8VYkRCx3uqU8NHPlOxPGhxPAyArBkT9H8Qzb5DQvwpKIpWAj4AG8RaAi294DrjjV/D U80LVe9hH+urgHZn2yCzQ3Fi+uVNgtB6rxQGV/ewz+lgsvXafca9YvZ++u9pHA1oXusf Fuxliq/xNemOZaG5s2OxN1eYYxDjlnA568wXHuWSFiRUILr+FU7/VlIWKjcTMewZTu3O B6mkrdy+xYMhc5ePi26Gn2eilh25MpORRwpsHuzqT0/g1dTO7u7Pd9RhSdUeL2W8HKPM oiXg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=Fz4rjXU4pv+JoX8GiRxuwd31ga6ygJiOfjuBNAA23TI=; b=lSOKYyuuG7k9PoOUo09kQHXkb0UegW1EMQJcc6mNYAJolX1sueogcNBS11Sw+UNtZy oBy1GWRKWm/SnaKBTl/+hutfxR8hvu43DblS+oHNLqSEM+D2ILeyOyH024oKpDUEWy91 HlljOc0VO/oLJ0QasaA0B/As91aE88q5nqbsXpl5YcPuBHgfaq7tFVxIb8Awt2tX8u9k zxQie34o5YRQDKHlSOSisowaThyKi1gxNc0PLJZEhZ3yU0RB57rL8K+A3NCYoHatj1FJ gtXZzof4D/l+ZexovMe9/DC8nZlwFkHI4qDGo+7jx70iNJnDPsSjxaq+Hlu3K0eSBzsK N72Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b=TFaKHOzs; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id x6-20020aa79566000000b005a8ac9f6462si608800pfq.72.2023.03.02.15.47.05; Thu, 02 Mar 2023 15:47:18 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b=TFaKHOzs; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229991AbjCBX2Y (ORCPT + 99 others); Thu, 2 Mar 2023 18:28:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45102 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229832AbjCBX2L (ORCPT ); Thu, 2 Mar 2023 18:28:11 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26C741994 for ; Thu, 2 Mar 2023 15:28:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=Fz4rjXU4pv+JoX8GiRxuwd31ga6ygJiOfjuBNAA23TI=; b=TFaKHOzs5zZrjEDnSHRp+DurxS EZpK7uL5ROEanWcdSjADz8IiT9IvqFH7WDeg96aXeb7m3m2MRMicspkiYt/i4MJb32izDxDrcXfkR Ds12Y4SSHzRZi2EavEPEHkitO37g6qnc2bqD93P2Sq+ov2YZdiNMiwq8LHIGSBEKfaxEzkuVTb/Li eyQolkb0Tm/6Zpnk/sRhTSjX8E0AO5dabHME4Z4quDrlZlNbzf2m9AK6EB8FSAvjOQwlwch64nCYm vap3IRDQrZhqDi0Vi31lW7yLoGiYQQ7Tck2NBz7gPOMSSu22zuLA/5dPm8V7ADT8iujNfWaqSicNC 2GU4CIiQ==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pXsL9-003j3K-61; Thu, 02 Mar 2023 23:27:59 +0000 From: Luis Chamberlain To: hughd@google.com, akpm@linux-foundation.org, willy@infradead.org, brauner@kernel.org Cc: linux-mm@kvack.org, p.raghav@samsung.com, da.gomez@samsung.com, a.manzanares@samsung.com, dave@stgolabs.net, yosryahmed@google.com, keescook@chromium.org, mcgrof@kernel.org, patches@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 2/6] shmem: set shmem_writepage() variables early Date: Thu, 2 Mar 2023 15:27:54 -0800 Message-Id: <20230302232758.888157-3-mcgrof@kernel.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20230302232758.888157-1-mcgrof@kernel.org> References: <20230302232758.888157-1-mcgrof@kernel.org> MIME-Version: 1.0 Sender: Luis Chamberlain X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1759301692079761629?= X-GMAIL-MSGID: =?utf-8?q?1759301692079761629?= shmem_writepage() sets up variables typically used *after* a possible huge page split. However even if that does happen the address space mapping should not change, and the inode does not change either. So it should be safe to set that from the very beginning. This commit makes no functional changes. Signed-off-by: Luis Chamberlain Acked-by: David Hildenbrand Reviewed-by: Christian Brauner --- mm/shmem.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 7fff1a3af092..2b9ff585a553 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1334,9 +1334,9 @@ int shmem_unuse(unsigned int type) static int shmem_writepage(struct page *page, struct writeback_control *wbc) { struct folio *folio = page_folio(page); - struct shmem_inode_info *info; - struct address_space *mapping; - struct inode *inode; + struct address_space *mapping = folio->mapping; + struct inode *inode = mapping->host; + struct shmem_inode_info *info = SHMEM_I(inode); swp_entry_t swap; pgoff_t index; @@ -1354,10 +1354,7 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) folio_clear_dirty(folio); } - mapping = folio->mapping; index = folio->index; - inode = mapping->host; - info = SHMEM_I(inode); if (info->flags & VM_LOCKED) goto redirty; if (!total_swap_pages) From patchwork Thu Mar 2 23:27:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Chamberlain X-Patchwork-Id: 63662 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:5915:0:0:0:0:0 with SMTP id v21csp128065wrd; Thu, 2 Mar 2023 15:48:15 -0800 (PST) X-Google-Smtp-Source: AK7set+k2HLUOMoLI3mj5v5+zH5fFwNSoXizhWgjiZA0s290tVlRfU1nmsCiXf8btc+vMudGPRIM X-Received: by 2002:a62:7bd3:0:b0:5ad:9f47:885b with SMTP id w202-20020a627bd3000000b005ad9f47885bmr142108pfc.31.1677800895587; Thu, 02 Mar 2023 15:48:15 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1677800895; cv=none; d=google.com; s=arc-20160816; b=CAhxTeNMuKvI1sSKiQoZpjHXLSNlmfTo6qbJFZE0uELn4SYWFdUySwaQh6SeTjoK67 bx93ZfX3DrtubGU+JIA3y1XKPXxHKTwCjQ6TZ9YvIDkLIMIcHteH9pCtkl6g6ygCC4P1 CAzsPvxOiw4ad1AlNhby/qhzSW+rgSowv+DJ803iuAHWA7krDo/0bpCdkeQRZPGjQQlt f4uY62t3e7UsES0z3vh+8XCW1Vnl3U0b4frwKM7iyY5JH6dMi1wZwbepPGTHWi/j+ZgM XCDsGMAsUiamWb5j7o17mTk+q60CAn50A3NL8XdtmZ4sfCcRRsfp51Wag+lDIaa+3wz7 TqGw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=Hpr/mKVZzGGQqVrubmxhAsrFv4PlfL2VXUxF3A6d69A=; b=LKwSlZRFqSq1hAMumMBlY0hgFF+5aojY2LQEqqw5h196iaOUp6F2ci8h8pD6MIbUCh 6pMOjBrlSC+qbAoIBG7YzXcsGv70U6bVQnSSyIHniJuExsGDWZjwmD9QdUInP6Cz0mA1 rKoymObju+9TKMaXAKPi5ojLT4bV/HY5ZyLWg23AcW9dIZrjh0PkVTy13YhmMF51lY1A xPx9Wk4i+6OOIH4jfBMOuOwx8pdCnksZ0Nw0f96EC8QKQYKS/9tBdEtxTvIbxE+9k+Ew +pLDdkI3k6GhARQXsM9cLLpBBrrPj1BoOUNf12ziWTurABD2InUTy639WOXznRDdoP1t jE9A== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b=hKi5B7rk; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id r26-20020aa79eda000000b005a8dcaeba57si540666pfq.371.2023.03.02.15.47.59; Thu, 02 Mar 2023 15:48:15 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b=hKi5B7rk; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230049AbjCBX21 (ORCPT + 99 others); Thu, 2 Mar 2023 18:28:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45120 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229936AbjCBX2L (ORCPT ); Thu, 2 Mar 2023 18:28:11 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4A55C125BF for ; Thu, 2 Mar 2023 15:28:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=Hpr/mKVZzGGQqVrubmxhAsrFv4PlfL2VXUxF3A6d69A=; b=hKi5B7rksyIKLYpIpojH3COwse 6yVboytacnRm0DNMUh5BKMfZwbdWYuNUklJLKFbD4wjEle33GCTpvZJdXbQPCk3hIf0DFStd9tL+t jq4IAgiksjYqh8v8mIireTRU6LNVj2zfYQ9mtUda+GZCTq6XHxJgjkKPxVVTVA6t/x9znl5F31erd JzgAsoy7GHNSk6QSSzDOJz7LMMAQ1DbbEpT234nu/jFOtmuCwstY5Gm50cCZVHGdz0FpM/qmB87KL Z3RJNpaMrZyQyQJFwvIzGInyQpaIjBIYAAKuhUc2yvfiaKNxUBSuS7LOizfLNgOD6cguhCKiDt7p1 C3zX/D7w==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pXsL9-003j3M-8Z; Thu, 02 Mar 2023 23:27:59 +0000 From: Luis Chamberlain To: hughd@google.com, akpm@linux-foundation.org, willy@infradead.org, brauner@kernel.org Cc: linux-mm@kvack.org, p.raghav@samsung.com, da.gomez@samsung.com, a.manzanares@samsung.com, dave@stgolabs.net, yosryahmed@google.com, keescook@chromium.org, mcgrof@kernel.org, patches@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 3/6] shmem: move reclaim check early on writepages() Date: Thu, 2 Mar 2023 15:27:55 -0800 Message-Id: <20230302232758.888157-4-mcgrof@kernel.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20230302232758.888157-1-mcgrof@kernel.org> References: <20230302232758.888157-1-mcgrof@kernel.org> MIME-Version: 1.0 Sender: Luis Chamberlain X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1759301751851138697?= X-GMAIL-MSGID: =?utf-8?q?1759301751851138697?= i915_gem requires huge folios to be split when swapping. However we have check for usage of writepages() to ensure it used only for swap purposes later. Avoid the splits if we're not being called for reclaim, even if they should in theory not happen. This makes the conditions easier to follow on shem_writepage(). Signed-off-by: Luis Chamberlain Acked-by: David Hildenbrand Reviewed-by: Yosry Ahmed --- mm/shmem.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 2b9ff585a553..a5a6da51087e 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1340,6 +1340,18 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) swp_entry_t swap; pgoff_t index; + /* + * Our capabilities prevent regular writeback or sync from ever calling + * shmem_writepage; but a stacking filesystem might use ->writepage of + * its underlying filesystem, in which case tmpfs should write out to + * swap only in response to memory pressure, and not for the writeback + * threads or sync. + */ + if (!wbc->for_reclaim) { + WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ + goto redirty; + } + /* * If /sys/kernel/mm/transparent_hugepage/shmem_enabled is "always" or * "force", drivers/gpu/drm/i915/gem/i915_gem_shmem.c gets huge pages, @@ -1360,18 +1372,6 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) if (!total_swap_pages) goto redirty; - /* - * Our capabilities prevent regular writeback or sync from ever calling - * shmem_writepage; but a stacking filesystem might use ->writepage of - * its underlying filesystem, in which case tmpfs should write out to - * swap only in response to memory pressure, and not for the writeback - * threads or sync. - */ - if (!wbc->for_reclaim) { - WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ - goto redirty; - } - /* * This is somewhat ridiculous, but without plumbing a SWAP_MAP_FALLOC * value into swapfile.c, the only way we can correctly account for a From patchwork Thu Mar 2 23:27:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Chamberlain X-Patchwork-Id: 63657 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:5915:0:0:0:0:0 with SMTP id v21csp127079wrd; Thu, 2 Mar 2023 15:45:02 -0800 (PST) X-Google-Smtp-Source: AK7set8YGv5+xotLLXrmFzESHxtDD+SuCPEpTTMpISkPUgOJ1YPKy7ycs/klw1p45sxy5gvMhBw2 X-Received: by 2002:a17:90b:3912:b0:234:e3f:f53b with SMTP id ob18-20020a17090b391200b002340e3ff53bmr13179914pjb.21.1677800702053; Thu, 02 Mar 2023 15:45:02 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1677800702; cv=none; d=google.com; s=arc-20160816; b=a4kzB44aKE7qh/c90Jao+C8PrHG5QmGS0mkTaoXvQJ+D021Ha2lch1QcdlCOq2tWQS FltrFtCTbgaYu2FV19bSBVMWrdJSD0KV2v+bwxsxQ/eNsHCrxdMAQoqEsAIzSVezzlJt 7myyovH4kl716pyXhIUkIVoSAJIGA4iwF6jL8wCdl03OEu65rGW0xpgxV2BCqM+nf3nn 1MB3xZYUmSX0o6dsrHjxCRfwitQpSQEPlu2Mi+eSTDl3p/9eay2m6nyKTcVQTlq5F19J utHCU4DsORKzPdZLvy9qoNG0fXUsPItDn6LKolE5hIAl04HqMJ+GGLHyqRVdm6fDfSP0 Z7Fg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=qG5U0uWPFmEbIzb8qGwDd3VP74J/BRogOkPK92T1eiw=; b=U9JldxxzqjHfWyQC+dAqYPVYqQz+ZSy3gJ+ERuoT3bgIv9I13OztstavoodctQrc1v iBAIwe6Cyj7fPs6ehpDUhs1YEn679pGo0EoMRKErhFjjXcAetj6Ulaw4oUhSYPD0AZtK nR5EC7hYjYaSKzwUYDrWjgjxf0FEPI0i6MC2xMCFidlZqJOZ1ejzkUt2aUwZNHixfziQ xld46X/H6/0BYPRyWGZqKdAQbmm7LcR/G1O5Z4zzRvGc7zAAgh8mRbavumipcmvQBgUU aKzQTBhZS3ZWG53WrhS0VXGEckT3n3RLmLR1kR3b0C4nGy4F7mrkPJM9MLU8gu6Bp7Mj rOVA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b=4Mn4cSCA; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id lb3-20020a17090b4a4300b00233e4acc8d5si731436pjb.170.2023.03.02.15.44.46; Thu, 02 Mar 2023 15:45:02 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b=4Mn4cSCA; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229947AbjCBX2M (ORCPT + 99 others); Thu, 2 Mar 2023 18:28:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45086 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229458AbjCBX2L (ORCPT ); Thu, 2 Mar 2023 18:28:11 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CAC5212598 for ; Thu, 2 Mar 2023 15:28:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=qG5U0uWPFmEbIzb8qGwDd3VP74J/BRogOkPK92T1eiw=; b=4Mn4cSCAgRAwfc+ofEk7syFvU4 lgI+PixYXC7I6rMVPFt85Y4M8oB/dWwp5q6YY7j/3hgM2uh2P7ZtiZ22ho1zzeWefT3wd+huLJpxd mvGW2hfn1RtW61xAcyyeVfH9HN8JlRi29H3roFcGHcEC+b/G8QXX5LxaV7GoFHadburRxTnA/MMf9 +OPgxbeXJdcEcdQlRLQ0xbxT//SyOp14A7a7SO3dbpZWiKOO2+0j1sd9qtehWMvQZKVPoRxZhSOC9 XOO9h5XjMa5XF91JikH0HlR1tccdHYPW2mUwbxqK+PvPIFK+WTgqQha6vzzE6HKxjq0hmzN8pLejD /ppNx6LQ==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pXsL9-003j3O-BB; Thu, 02 Mar 2023 23:27:59 +0000 From: Luis Chamberlain To: hughd@google.com, akpm@linux-foundation.org, willy@infradead.org, brauner@kernel.org Cc: linux-mm@kvack.org, p.raghav@samsung.com, da.gomez@samsung.com, a.manzanares@samsung.com, dave@stgolabs.net, yosryahmed@google.com, keescook@chromium.org, mcgrof@kernel.org, patches@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 4/6] shmem: skip page split if we're not reclaiming Date: Thu, 2 Mar 2023 15:27:56 -0800 Message-Id: <20230302232758.888157-5-mcgrof@kernel.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20230302232758.888157-1-mcgrof@kernel.org> References: <20230302232758.888157-1-mcgrof@kernel.org> MIME-Version: 1.0 Sender: Luis Chamberlain X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1759301549041746379?= X-GMAIL-MSGID: =?utf-8?q?1759301549041746379?= In theory when info->flags & VM_LOCKED we should not be getting shem_writepage() called so we should be verifying this with a WARN_ON_ONCE(). Since we should not be swapping then best to ensure we also don't do the folio split earlier too. So just move the check early to avoid folio splits in case its a dubious call. We also have a similar early bail when !total_swap_pages so just move that earlier to avoid the possible folio split in the same situation. Signed-off-by: Luis Chamberlain Acked-by: David Hildenbrand Reviewed-by: Yosry Ahmed --- mm/shmem.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index a5a6da51087e..6006dbb7dbcb 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1352,6 +1352,12 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) goto redirty; } + if (WARN_ON_ONCE(info->flags & VM_LOCKED)) + goto redirty; + + if (!total_swap_pages) + goto redirty; + /* * If /sys/kernel/mm/transparent_hugepage/shmem_enabled is "always" or * "force", drivers/gpu/drm/i915/gem/i915_gem_shmem.c gets huge pages, @@ -1367,10 +1373,6 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) } index = folio->index; - if (info->flags & VM_LOCKED) - goto redirty; - if (!total_swap_pages) - goto redirty; /* * This is somewhat ridiculous, but without plumbing a SWAP_MAP_FALLOC From patchwork Thu Mar 2 23:27:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Chamberlain X-Patchwork-Id: 63658 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:5915:0:0:0:0:0 with SMTP id v21csp127080wrd; Thu, 2 Mar 2023 15:45:02 -0800 (PST) X-Google-Smtp-Source: AK7set/Nb5ZXcwSbJgCwWBuyWCWdR7pL/9zaI1D9Wt9u00yTRDpDia0LcV9MiF22pF4TWN5Z05qQ X-Received: by 2002:a17:90b:1b4c:b0:23a:333c:6bab with SMTP id nv12-20020a17090b1b4c00b0023a333c6babmr5010508pjb.23.1677800702074; Thu, 02 Mar 2023 15:45:02 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1677800702; cv=none; d=google.com; s=arc-20160816; b=1E+5A56/tWcZ/59sILbP2U4/3oBxkM9fnk0voaLGBU9YpKvtPHyySzkhrs9JvAbPh6 Dw3WWEvok0rmCqQj6+RFMiJlS4Ht2qtRdrfZCY00LRGvXftUCZOzJpucf0i08R39gDgh KkM/XJ544ESX0Zam5rXzsSYrrKGS8AuSWOIKjEZAyyrN8vWs/aIQ3kee6ftmGJwkfofG FX73Z/WbOTKyHmqk5iJ279JydBHYfDc++vRpq4HmpSFkIoQXGND7PoSPy4+Y93fKEebc aY27Vd0+PRk73O6B5UDx3TTwl0bvsOl463MN55gCgHfYRHmeTQvsun9gIjjM1RZwexSz 14mg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=skC96Wt8xxhIMwjo9L+gt44Hnic6JkSNTvyHUyToP4E=; b=eizJtK40rUM6bA5Atpk790jXo8C4F1cu2a1KHQKFCL/8nvAuEY1VdS1eyAVXpYBrU0 s0N3OW+siLKlLakWXWMmFkE2APNlW4XiixMl/GjaVSSxpgkBOoe+Sx7+BZXKQRPxe/rU WwrSkti5BZMEDGHqcUIsM3dNVZtW0vAnJptaaJiGwSk47EGN4C9NfIpB8SlRT8Z6IpIX aeBJqdGAJFkwgTAw9t8ZAY88c2hVDaVqx9Obgg/8aZtEe7DVzDXLFlvb3Q4H+7h1q6Lv OH98BEowhXih1Z6iufN+trkosj5jVZ/WQ9Avmj1G5OARciS/kDhBggOyKRtCFGOteyZp rLSQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b="K/eQSla3"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id q8-20020a17090a1b0800b002340f36b545si730325pjq.18.2023.03.02.15.44.47; Thu, 02 Mar 2023 15:45:02 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b="K/eQSla3"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229969AbjCBX2O (ORCPT + 99 others); Thu, 2 Mar 2023 18:28:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45094 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229797AbjCBX2L (ORCPT ); Thu, 2 Mar 2023 18:28:11 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA7A111679 for ; Thu, 2 Mar 2023 15:28:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=skC96Wt8xxhIMwjo9L+gt44Hnic6JkSNTvyHUyToP4E=; b=K/eQSla3MTHn7M0Rb9rcMYDVlA e37q4SAkKhrm7U/RKwrVlRksYjpLSQ7cyFhGajl9HtpsHsUn6N0cRNl0Qv09F6TFF8NJALHGbqV9Y MKle2ZzppMMuer2n5cLdK6TEumXDYu//CEasZglQ4GBDSIpbcgf9zrLrspyNLR57fU9TjiN84RzjX DJKtgrXnUJH4f9ErONxxluGJkBZMTUgr6znqZikMJYzDqfZ43mgtSToV2ADG2RhlMqjD5DNDGVY4q QwjsemBTEGNoJzgAOOd9LwEPm7jsyyl3cLget4EvACCEKtoo27Ivb7ie0zI+m3cji7ZAqVl11QKp8 lTov+nwA==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pXsL9-003j3Q-Dq; Thu, 02 Mar 2023 23:27:59 +0000 From: Luis Chamberlain To: hughd@google.com, akpm@linux-foundation.org, willy@infradead.org, brauner@kernel.org Cc: linux-mm@kvack.org, p.raghav@samsung.com, da.gomez@samsung.com, a.manzanares@samsung.com, dave@stgolabs.net, yosryahmed@google.com, keescook@chromium.org, mcgrof@kernel.org, patches@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 5/6] shmem: update documentation Date: Thu, 2 Mar 2023 15:27:57 -0800 Message-Id: <20230302232758.888157-6-mcgrof@kernel.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20230302232758.888157-1-mcgrof@kernel.org> References: <20230302232758.888157-1-mcgrof@kernel.org> MIME-Version: 1.0 Sender: Luis Chamberlain X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1759301549263558894?= X-GMAIL-MSGID: =?utf-8?q?1759301549263558894?= Update the docs to reflect a bit better why some folks prefer tmpfs over ramfs and clarify a bit more about the difference between brd ramdisks. Signed-off-by: Luis Chamberlain Reviewed-by: David Hildenbrand Reviewed-by: Christian Brauner --- Documentation/filesystems/tmpfs.rst | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst index 0408c245785e..e77ebdacadd0 100644 --- a/Documentation/filesystems/tmpfs.rst +++ b/Documentation/filesystems/tmpfs.rst @@ -13,14 +13,25 @@ everything stored therein is lost. tmpfs puts everything into the kernel internal caches and grows and shrinks to accommodate the files it contains and is able to swap -unneeded pages out to swap space. It has maximum size limits which can -be adjusted on the fly via 'mount -o remount ...' - -If you compare it to ramfs (which was the template to create tmpfs) -you gain swapping and limit checking. Another similar thing is the RAM -disk (/dev/ram*), which simulates a fixed size hard disk in physical -RAM, where you have to create an ordinary filesystem on top. Ramdisks -cannot swap and you do not have the possibility to resize them. +unneeded pages out to swap space. + +tmpfs extends ramfs with a few userspace configurable options listed and +explained further below, some of which can be reconfigured dynamically on the +fly using a remount ('mount -o remount ...') of the filesystem. A tmpfs +filesystem can be resized but it cannot be resized to a size below its current +usage. tmpfs also supports POSIX ACLs, and extended attributes for the +trusted.* and security.* namespaces. ramfs does not use swap and you cannot +modify any parameter for a ramfs filesystem. The size limit of a ramfs +filesystem is how much memory you have available, and so care must be taken if +used so to not run out of memory. + +An alternative to tmpfs and ramfs is to use brd to create RAM disks +(/dev/ram*), which allows you to simulate a block device disk in physical RAM. +To write data you would just then need to create an regular filesystem on top +this ramdisk. As with ramfs, brd ramdisks cannot swap. brd ramdisks are also +configured in size at initialization and you cannot dynamically resize them. +Contrary to brd ramdisks, tmpfs has its own filesystem, it does not rely on the +block layer at all. Since tmpfs lives completely in the page cache and on swap, all tmpfs pages will be shown as "Shmem" in /proc/meminfo and "Shared" in From patchwork Thu Mar 2 23:27:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Chamberlain X-Patchwork-Id: 63660 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:5915:0:0:0:0:0 with SMTP id v21csp127484wrd; Thu, 2 Mar 2023 15:46:17 -0800 (PST) X-Google-Smtp-Source: AK7set9HZobDf/PXqxHSqHM8b84dwX58ADFcpOZRYhvw3TyKlSVEWUJyjtxauzak/iYYpn2jwoem X-Received: by 2002:a17:90b:3847:b0:233:e1e6:33d4 with SMTP id nl7-20020a17090b384700b00233e1e633d4mr13513306pjb.47.1677800777132; Thu, 02 Mar 2023 15:46:17 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1677800777; cv=none; d=google.com; s=arc-20160816; b=uL64U/NszNjZiRhAVlw9BYwJRMXFMw+RBcEj/7oj40U+XTPKnCo7zMTfIwMBvG5eqp LkA60s453XAmuCoKldLFbFG4DmF56VJSNpqhaYrJ75WqZgb996UfbAyGuL/MZWhwz1Au /9dMBx66i/brkqZn/0XR2jRacWpsUZy4ZGdd95s+W5YoINBY7PL+0VGKE2r08faEwsFK Xao2OL8/tx8E4j728Ezqt4B2GRjjpgy0I+4wtliJyepdf5BEyZy9a2o5KjeYKLvDCBYo +iruFNXV4HUYduDfcxyv8gK2F5ey/u7HQg5d8aP91Tk5BhYa8n/Us6Kcj40b4glVJQXW t6Cw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=aVGWGg28pehMWy6o19l/TsZGWBXxeVmCZNXdGLwnZq4=; b=UW/3TAmwjilOVbhcMEFJ+PtuxWWgkOm6v9mhj8617IdXPzYOpJl15PVDKfUVs95mqY fhHMIaA1noXpNstjcG8VxGnSgKqLcf5/6mbdQelbjwphY4qQwuzYY8TrtNcWi5hb0N9N PofmYXk6I3ujgAOOO7sld9qZsFWkEXLBKspz6oOiGHfcNmbkXXqxn66Hblb8dcJW5Lvv V6erVtGYCL8o9FiWyLIaU3OU98l5a4b2DHR7DDzy+JFOV5ihSO+tva1HSiaqQEwndzIP iJMUhovXeUeQu2x8Weh29eCodbj15w6GfJ4FIKotMHdRMWJ+fVxQlDYx9kuHtDyA1vo4 0T8Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b=TlDiW9om; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id lb3-20020a17090b4a4300b00233e4acc8d5si731436pjb.170.2023.03.02.15.46.03; Thu, 02 Mar 2023 15:46:17 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b=TlDiW9om; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230000AbjCBX2U (ORCPT + 99 others); Thu, 2 Mar 2023 18:28:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45106 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229933AbjCBX2L (ORCPT ); Thu, 2 Mar 2023 18:28:11 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CA90011E94 for ; Thu, 2 Mar 2023 15:28:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=aVGWGg28pehMWy6o19l/TsZGWBXxeVmCZNXdGLwnZq4=; b=TlDiW9om0AtjuznlGSshw1b4sC ghR2WXi7V+f5PZ1jG/o45vCIdVVPAervPRo0lvMQJdxtcovf9IN60XRQyXJ1TOSoZDYvbKBXbI/Wi kuqHDamMQIx8Oh2hC1RmvcgDdngdxl8vCJelPxKnPdI6sZqCLJP7oKLTX7HCNfOVjJ+oJWhrHo56l jIjCnoGvXoEsBAierza5C+Z0oTy0fXnLWb9sfdDC4drisylwEXR0+Vwcjgn7AYvnMbzbxgtrQjiQg eoDfsRFufkoQ6AunUMT7LpC6d+FMUW/ESv6NhPIS/cqtmkwozQFqphCo+anHmfRTZfKqu4eV620Lr q5ku9HZg==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pXsL9-003j3S-Gf; Thu, 02 Mar 2023 23:27:59 +0000 From: Luis Chamberlain To: hughd@google.com, akpm@linux-foundation.org, willy@infradead.org, brauner@kernel.org Cc: linux-mm@kvack.org, p.raghav@samsung.com, da.gomez@samsung.com, a.manzanares@samsung.com, dave@stgolabs.net, yosryahmed@google.com, keescook@chromium.org, mcgrof@kernel.org, patches@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH 6/6] shmem: add support to ignore swap Date: Thu, 2 Mar 2023 15:27:58 -0800 Message-Id: <20230302232758.888157-7-mcgrof@kernel.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20230302232758.888157-1-mcgrof@kernel.org> References: <20230302232758.888157-1-mcgrof@kernel.org> MIME-Version: 1.0 Sender: Luis Chamberlain X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1759301627613678800?= X-GMAIL-MSGID: =?utf-8?q?1759301627613678800?= In doing experimentations with shmem having the option to avoid swap becomes a useful mechanism. One of the *raves* about brd over shmem is you can avoid swap, but that's not really a good reason to use brd if we can instead use shmem. Using brd has its own good reasons to exist, but just because "tmpfs" doesn't let you do that is not a great reason to avoid it if we can easily add support for it. I don't add support for reconfiguring incompatible options, but if we really wanted to we can add support for that. To avoid swap we use mapping_set_unevictable() upon inode creation, and put a WARN_ON_ONCE() stop-gap on writepages() for reclaim. Acked-by: Christian Brauner Signed-off-by: Luis Chamberlain --- Documentation/filesystems/tmpfs.rst | 9 ++++++--- Documentation/mm/unevictable-lru.rst | 2 ++ include/linux/shmem_fs.h | 1 + mm/shmem.c | 28 +++++++++++++++++++++++++++- 4 files changed, 36 insertions(+), 4 deletions(-) diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst index e77ebdacadd0..551b621f34d9 100644 --- a/Documentation/filesystems/tmpfs.rst +++ b/Documentation/filesystems/tmpfs.rst @@ -13,7 +13,8 @@ everything stored therein is lost. tmpfs puts everything into the kernel internal caches and grows and shrinks to accommodate the files it contains and is able to swap -unneeded pages out to swap space. +unneeded pages out to swap space, if swap was enabled for the tmpfs +filesystem. tmpfs extends ramfs with a few userspace configurable options listed and explained further below, some of which can be reconfigured dynamically on the @@ -33,8 +34,8 @@ configured in size at initialization and you cannot dynamically resize them. Contrary to brd ramdisks, tmpfs has its own filesystem, it does not rely on the block layer at all. -Since tmpfs lives completely in the page cache and on swap, all tmpfs -pages will be shown as "Shmem" in /proc/meminfo and "Shared" in +Since tmpfs lives completely in the page cache and on optionally on swap, +all tmpfs pages will be shown as "Shmem" in /proc/meminfo and "Shared" in free(1). Notice that these counters also include shared memory (shmem, see ipcs(1)). The most reliable way to get the count is using df(1) and du(1). @@ -83,6 +84,8 @@ nr_inodes The maximum number of inodes for this instance. The default is half of the number of your physical RAM pages, or (on a machine with highmem) the number of lowmem RAM pages, whichever is the lower. +noswap Disables swap. Remounts must respect the original settings. + By default swap is enabled. ========= ============================================================ These parameters accept a suffix k, m or g for kilo, mega and giga and diff --git a/Documentation/mm/unevictable-lru.rst b/Documentation/mm/unevictable-lru.rst index 92ac5dca420c..3cdcbb6e00a0 100644 --- a/Documentation/mm/unevictable-lru.rst +++ b/Documentation/mm/unevictable-lru.rst @@ -42,6 +42,8 @@ The unevictable list addresses the following classes of unevictable pages: * Those owned by ramfs. + * Those owned by tmpfs with the noswap option. + * Those mapped into SHM_LOCK'd shared memory regions. * Those mapped into VM_LOCKED [mlock()ed] VMAs. diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index 103d1000a5a2..21989d4f8cbe 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -45,6 +45,7 @@ struct shmem_sb_info { kuid_t uid; /* Mount uid for root directory */ kgid_t gid; /* Mount gid for root directory */ bool full_inums; /* If i_ino should be uint or ino_t */ + bool noswap; /* ingores VM relcaim / swap requests */ ino_t next_ino; /* The next per-sb inode number to use */ ino_t __percpu *ino_batch; /* The next per-cpu inode number to use */ struct mempolicy *mpol; /* default memory policy for mappings */ diff --git a/mm/shmem.c b/mm/shmem.c index 6006dbb7dbcb..cd36cb3d974c 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -119,10 +119,12 @@ struct shmem_options { bool full_inums; int huge; int seen; + bool noswap; #define SHMEM_SEEN_BLOCKS 1 #define SHMEM_SEEN_INODES 2 #define SHMEM_SEEN_HUGE 4 #define SHMEM_SEEN_INUMS 8 +#define SHMEM_SEEN_NOSWAP 16 }; #ifdef CONFIG_TMPFS @@ -1337,6 +1339,7 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) struct address_space *mapping = folio->mapping; struct inode *inode = mapping->host; struct shmem_inode_info *info = SHMEM_I(inode); + struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); swp_entry_t swap; pgoff_t index; @@ -1352,7 +1355,7 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) goto redirty; } - if (WARN_ON_ONCE(info->flags & VM_LOCKED)) + if (WARN_ON_ONCE((info->flags & VM_LOCKED) || sbinfo->noswap)) goto redirty; if (!total_swap_pages) @@ -2489,6 +2492,8 @@ static struct inode *shmem_get_inode(struct mnt_idmap *idmap, struct super_block shmem_set_inode_flags(inode, info->fsflags); INIT_LIST_HEAD(&info->shrinklist); INIT_LIST_HEAD(&info->swaplist); + if (sbinfo->noswap) + mapping_set_unevictable(inode->i_mapping); simple_xattrs_init(&info->xattrs); cache_no_acl(inode); mapping_set_large_folios(inode->i_mapping); @@ -3576,6 +3581,7 @@ enum shmem_param { Opt_uid, Opt_inode32, Opt_inode64, + Opt_noswap, }; static const struct constant_table shmem_param_enums_huge[] = { @@ -3597,6 +3603,7 @@ const struct fs_parameter_spec shmem_fs_parameters[] = { fsparam_u32 ("uid", Opt_uid), fsparam_flag ("inode32", Opt_inode32), fsparam_flag ("inode64", Opt_inode64), + fsparam_flag ("noswap", Opt_noswap), {} }; @@ -3680,6 +3687,10 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param) ctx->full_inums = true; ctx->seen |= SHMEM_SEEN_INUMS; break; + case Opt_noswap: + ctx->noswap = true; + ctx->seen |= SHMEM_SEEN_NOSWAP; + break; } return 0; @@ -3778,6 +3789,14 @@ static int shmem_reconfigure(struct fs_context *fc) err = "Current inum too high to switch to 32-bit inums"; goto out; } + if ((ctx->seen & SHMEM_SEEN_NOSWAP) && ctx->noswap && !sbinfo->noswap) { + err = "Cannot disable swap on remount"; + goto out; + } + if (!(ctx->seen & SHMEM_SEEN_NOSWAP) && !ctx->noswap && sbinfo->noswap) { + err = "Cannot enable swap on remount if it was disabled on first mount"; + goto out; + } if (ctx->seen & SHMEM_SEEN_HUGE) sbinfo->huge = ctx->huge; @@ -3798,6 +3817,10 @@ static int shmem_reconfigure(struct fs_context *fc) sbinfo->mpol = ctx->mpol; /* transfers initial ref */ ctx->mpol = NULL; } + + if (ctx->noswap) + sbinfo->noswap = true; + raw_spin_unlock(&sbinfo->stat_lock); mpol_put(mpol); return 0; @@ -3852,6 +3875,8 @@ static int shmem_show_options(struct seq_file *seq, struct dentry *root) seq_printf(seq, ",huge=%s", shmem_format_huge(sbinfo->huge)); #endif shmem_show_mpol(seq, sbinfo->mpol); + if (sbinfo->noswap) + seq_printf(seq, ",noswap"); return 0; } @@ -3895,6 +3920,7 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc) ctx->inodes = shmem_default_max_inodes(); if (!(ctx->seen & SHMEM_SEEN_INUMS)) ctx->full_inums = IS_ENABLED(CONFIG_TMPFS_INODE64); + sbinfo->noswap = ctx->noswap; } else { sb->s_flags |= SB_NOUSER; }