From patchwork Mon Oct 24 20:48:29 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 10365 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:6687:0:0:0:0:0 with SMTP id l7csp685801wru; Mon, 24 Oct 2022 15:41:16 -0700 (PDT) X-Google-Smtp-Source: AMsMyM5lOd+Q1iLhntkWjxRf7vdT3At/drYbvblL55MoMKu1KP2p4T3FWnXy25Zi5oQV6f2IB8m9 X-Received: by 2002:a50:cc07:0:b0:453:4427:a918 with SMTP id m7-20020a50cc07000000b004534427a918mr32809013edi.121.1666651276510; Mon, 24 Oct 2022 15:41:16 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1666651276; cv=none; d=google.com; s=arc-20160816; b=xfWTKxWYUpiBv/MKK3mpVPGTB+NKL1Hkx1nUG//E15v1jwBXJFdDrYjtnVWJf+NGas 1QDd1KgHeqmwigho7jjYoVJBCZNTz7Kk8cF2dTi/lNvhtp5zrxJES9F+MEhTJYji8lN+ EQHFvaQQDhY3iIQEOy3bo74+V6wmtNV8/DXpfS4Jba/mJn1F/IlHYP4c80r5GaOFOvEs T8lqdRFZfMilzFfr1HwryuncPXBiOTmzz3fOTEkgD3nrZtp5dPNBwP/11tzqn8PX9Xb1 73cPj1Sz8vc0ydmn8XHr5bqLYJ2fZRBiOKD4r2ecdZBSr5VV5ixI1VWIueBrPnQ+VAbC XUZQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=DtjgD11+A1aHTX9ijK54hqLSilN13SGt8oWF8m3PTwE=; b=V9IHWof89EzS0j9UUEW9lSDJxN53hSQTkQ1gKhHoiepn9fRKqsHirWJliXnQiHoPES gQw+Ggtg1eePTDZdhS68U95BEwha+hnV/yLKGc7i3o9XM9Q9SluH3GtIr+MMu8IzSwOj 58tY9vD6IeZQuSBg5Q5oh4YrU8h0pwQjjA+GZHdUBrRbp/CQkiEIO8WtiNp7Gl4XnSd1 HQmtyj2Q86F26n3GMOrdoSsI9L7KdHnVh4yQgKTfwx0MTJssMdPUGL4kEpNCprjjkZbs 4NUWyOGB+uMsrk307Lo4aohAJt+M56SdpNNmjbSb1LbB19NsmGVGpZmOWxrxp3mdhNm3 7Ksw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=CBuUvnxk; 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=redhat.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id ev15-20020a17090729cf00b0073da5c8de1asi833804ejc.178.2022.10.24.15.40.50; Mon, 24 Oct 2022 15:41:16 -0700 (PDT) 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=@redhat.com header.s=mimecast20190719 header.b=CBuUvnxk; 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=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231698AbiJXWkX (ORCPT + 99 others); Mon, 24 Oct 2022 18:40:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36958 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232500AbiJXWjk (ORCPT ); Mon, 24 Oct 2022 18:39:40 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E432EF615F for ; Mon, 24 Oct 2022 14:03:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666645323; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=DtjgD11+A1aHTX9ijK54hqLSilN13SGt8oWF8m3PTwE=; b=CBuUvnxkNwqNKVplwTRSKew9k6CUd9gp3TWw1ZVgpTqYfKE+zKlXXb0wzdmHQVNDr3eYA8 i7n6ZEXQ+Je6yEfXbgezi+cCtYes7kA5/KqTyxecK9NQ9wLd56S4vYbDydEatD1iGOP9Wm 2emm3nKtWqrNyJ7lN2QAmz2/b4HzHr4= Received: from mail-qt1-f198.google.com (mail-qt1-f198.google.com [209.85.160.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-137-D6XI-4yAOcmMf0BzVEQIYA-1; Mon, 24 Oct 2022 16:48:46 -0400 X-MC-Unique: D6XI-4yAOcmMf0BzVEQIYA-1 Received: by mail-qt1-f198.google.com with SMTP id s14-20020a05622a1a8e00b00397eacd9c1aso7887661qtc.21 for ; Mon, 24 Oct 2022 13:48:46 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=DtjgD11+A1aHTX9ijK54hqLSilN13SGt8oWF8m3PTwE=; b=IKMKcOlrelexkH8gcseiASICBsQR8zzKniDFdN9o3qMs6d4yk1nFP2dv9kBjwASGm/ mKPEwqoreNG8uOYC4ubhnjEjXQgOLvJUfe7RJlMC3t4IqhrF1uk8OsT7WXBT0YqYaNzu O+od22A433/ERrKTQ5DJnGMkIYzOtHWpk24DLB/BQR3oMRYgV0zwkG3EyEbuoDKvhwFJ lDYuZUUa4+jb6ZZkmKwsn9B4f/IZ/WYHLMK7RByFkMPu6H8IqSVKOZ/bkpPmSeyzSOLz Dx57g6WN5RwcDoRobyonyXKadvcM+/DuwjuSAOWP1yTn5ltDDNrho/3iXp4LlvoAN9pm ycDw== X-Gm-Message-State: ACrzQf0yuqeHcPs5hdjOQuArDB1IhxdWtevijdCe4/760YnrBZqJOQ55 R57jryIG9QT8dNsiIQ5JY0xj9U0Ga+B8c4zZCBWY3n+//Wus33HyhFNjcMv8C0CcUCMYznJGKyl JO5x0kU0pcOfssnf6x0NzFy9nB89cXN4lfYx7EQP7yCvuRGaZ6ZvMlO/nT60ytndLVY3W09uxrA == X-Received: by 2002:a05:622a:13c8:b0:39c:c0aa:cdfa with SMTP id p8-20020a05622a13c800b0039cc0aacdfamr29059103qtk.251.1666644525095; Mon, 24 Oct 2022 13:48:45 -0700 (PDT) X-Received: by 2002:a05:620a:12ec:b0:6ee:9e71:190 with SMTP id f12-20020a05620a12ec00b006ee9e710190mr23862434qkl.527.1666644514574; Mon, 24 Oct 2022 13:48:34 -0700 (PDT) Received: from x1n.redhat.com (bras-base-aurron9127w-grc-46-70-31-27-79.dsl.bell.ca. [70.31.27.79]) by smtp.gmail.com with ESMTPSA id d13-20020ac8544d000000b0038d9555b580sm498531qtq.44.2022.10.24.13.48.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Oct 2022 13:48:34 -0700 (PDT) From: Peter Xu To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Huang Ying , peterx@redhat.com, Andrew Morton , HORIGUCHI NAOYA , Miaohe Lin , David Hildenbrand , Andrea Arcangeli Subject: [PATCH RFC 1/2] mm: Always compile in pte markers Date: Mon, 24 Oct 2022 16:48:29 -0400 Message-Id: <20221024204830.1342169-2-peterx@redhat.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221024204830.1342169-1-peterx@redhat.com> References: <20221024204830.1342169-1-peterx@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2,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?1747610528941414452?= X-GMAIL-MSGID: =?utf-8?q?1747610528941414452?= The PTE markers code is tiny and now it's enabled for most of the distributions. It's fine to keep it as-is, but to make a broader use of it (e.g. replacing read error swap entry) it needs to be there always otherwise we need special code path to take care of !PTE_MARKER case. It'll be easier just make pte marker always exist. Use this chance to extend its usage to anonymous too by simply touching up some of the old comments, because it'll be used for anonymous pages in the follow up patches. Signed-off-by: Peter Xu Reviewed-by: Miaohe Lin --- include/linux/swap.h | 10 +++------- include/linux/swapops.h | 31 ------------------------------- mm/Kconfig | 7 ------- mm/memory.c | 7 +++---- 4 files changed, 6 insertions(+), 49 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index 369d7799205d..211aeca9bfa7 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -60,17 +60,13 @@ static inline int current_is_kswapd(void) SWP_MIGRATION_NUM + SWP_DEVICE_NUM + \ SWP_PTE_MARKER_NUM) /* - * PTE markers are used to persist information onto PTEs that are mapped with - * file-backed memories. As its name "PTE" hints, it should only be applied to - * the leaves of pgtables. + * PTE markers are used to persist information onto PTEs that otherwise + * should be a none pte. As its name "PTE" hints, it should only be + * applied to the leaves of pgtables. */ -#ifdef CONFIG_PTE_MARKER #define SWP_PTE_MARKER_NUM 1 #define SWP_PTE_MARKER (MAX_SWAPFILES + SWP_HWPOISON_NUM + \ SWP_MIGRATION_NUM + SWP_DEVICE_NUM) -#else -#define SWP_PTE_MARKER_NUM 0 -#endif /* * Unaddressable device memory support. See include/linux/hmm.h and diff --git a/include/linux/swapops.h b/include/linux/swapops.h index 86b95ccb81bb..41a6e7b23415 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -412,8 +412,6 @@ typedef unsigned long pte_marker; #define PTE_MARKER_UFFD_WP BIT(0) #define PTE_MARKER_MASK (PTE_MARKER_UFFD_WP) -#ifdef CONFIG_PTE_MARKER - static inline swp_entry_t make_pte_marker_entry(pte_marker marker) { return swp_entry(SWP_PTE_MARKER, marker); @@ -434,32 +432,6 @@ static inline bool is_pte_marker(pte_t pte) return is_swap_pte(pte) && is_pte_marker_entry(pte_to_swp_entry(pte)); } -#else /* CONFIG_PTE_MARKER */ - -static inline swp_entry_t make_pte_marker_entry(pte_marker marker) -{ - /* This should never be called if !CONFIG_PTE_MARKER */ - WARN_ON_ONCE(1); - return swp_entry(0, 0); -} - -static inline bool is_pte_marker_entry(swp_entry_t entry) -{ - return false; -} - -static inline pte_marker pte_marker_get(swp_entry_t entry) -{ - return 0; -} - -static inline bool is_pte_marker(pte_t pte) -{ - return false; -} - -#endif /* CONFIG_PTE_MARKER */ - static inline pte_t make_pte_marker(pte_marker marker) { return swp_entry_to_pte(make_pte_marker_entry(marker)); @@ -477,9 +449,6 @@ static inline pte_t make_pte_marker(pte_marker marker) * memory, kernel-only memory (including when the system is during-boot), * non-ram based generic file-system. It's fine to be used even there, but the * extra pte marker check will be pure overhead. - * - * For systems configured with !CONFIG_PTE_MARKER this will be automatically - * optimized to pte_none(). */ static inline int pte_none_mostly(pte_t pte) { diff --git a/mm/Kconfig b/mm/Kconfig index 57e1d8c5b505..4b28800d9be1 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -1107,17 +1107,10 @@ config HAVE_ARCH_USERFAULTFD_MINOR help Arch has userfaultfd minor fault support -config PTE_MARKER - bool - - help - Allows to create marker PTEs for file-backed memory. - config PTE_MARKER_UFFD_WP bool "Userfaultfd write protection support for shmem/hugetlbfs" default y depends on HAVE_ARCH_USERFAULTFD_WP - select PTE_MARKER help Allows to create marker PTEs for userfaultfd write protection diff --git a/mm/memory.c b/mm/memory.c index 25b12d1a7db0..71114f05a68c 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3699,11 +3699,10 @@ static vm_fault_t handle_pte_marker(struct vm_fault *vmf) unsigned long marker = pte_marker_get(entry); /* - * PTE markers should always be with file-backed memories, and the - * marker should never be empty. If anything weird happened, the best - * thing to do is to kill the process along with its mm. + * PTE markers should never be empty. If anything weird happened, + * the best thing to do is to kill the process along with its mm. */ - if (WARN_ON_ONCE(vma_is_anonymous(vmf->vma) || !marker)) + if (WARN_ON_ONCE(!marker)) return VM_FAULT_SIGBUS; if (pte_marker_entry_uffd_wp(entry)) From patchwork Mon Oct 24 20:48:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 10363 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:6687:0:0:0:0:0 with SMTP id l7csp684101wru; Mon, 24 Oct 2022 15:36:34 -0700 (PDT) X-Google-Smtp-Source: AMsMyM5la2qdMT0ZAD5H9irQdYqCrLBrT6VGbxQpjsW+kyJqYI608F95s7sFjEB1Ym0shQ8MsVVc X-Received: by 2002:a05:6402:4441:b0:454:8a74:5459 with SMTP id o1-20020a056402444100b004548a745459mr32060818edb.155.1666650994190; Mon, 24 Oct 2022 15:36:34 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1666650994; cv=none; d=google.com; s=arc-20160816; b=qgjafH7x9ggoci6MhN0FOldI56/oKtjMmpobBaHQM7QoB/VH5BJSqoSpBnRLJrHksA +ArZjx2c187vwUD5SsTBjIS5AjEpGBVJMkpqApZ98jABA4LBPQeWkUEDvDw87V01QhLy 7GJes14Q9de4lIByqiIfa4r2hL3D5y67xQvvPFe5/nJZ+iGuokkiXPieeH2Cm5dL1WVa TjiYlG7eDIP1K+f2BhF2DLz9YV8bpXJpTS53bloC6dfXNu0oVmGYb4LEOUTaYP24x5bE zj1U4+JLx7V1LgWoDkUvxo1IkmuRJWEL1iexrFSttdzJ83z70r1CLLTohRvKV6P2QtxX Jy6Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=vZ6z2mx7oNlRshrZTg5WSyqHxrl+GaeTDPKlsjXuMmM=; b=CxJ21PN3lfmDPun7AsopPaRd4row6XleTT5qRM9jhWH0LCDLcXUGQhUeoBtTn+KOLe 87Wl5DMnuu5TXfyYw6miHftT3GYt7maAWzowbbDktmwh+AV9RHsFQqy3s/qLLof3Wc2P EFSUm0zb6oD8UJqLJ0+MsmDXbYcQOT2KRhn+6vjbbnWxKqEErEKrQORqZgiIsElly1v3 oGkkSo1S8o4WGzu9NKdP+lunYEw4O8sVJ/83HeYkx2Imu2sATzXUCcLB39t3+a0+wejG zuDAk4jAFByDgvVhrkCnxjLoS6y0nBEGCdhpLjA5BEudg8Ki12MT/JmXV/u/1F5r9hp9 I64Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=iGsbpUy3; 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=redhat.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id z16-20020a1709067e5000b0078bec673145si741743ejr.519.2022.10.24.15.36.09; Mon, 24 Oct 2022 15:36:34 -0700 (PDT) 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=@redhat.com header.s=mimecast20190719 header.b=iGsbpUy3; 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=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229956AbiJXWbN (ORCPT + 99 others); Mon, 24 Oct 2022 18:31:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43178 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231538AbiJXWan (ORCPT ); Mon, 24 Oct 2022 18:30:43 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 453592D128C for ; Mon, 24 Oct 2022 13:53:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666644721; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vZ6z2mx7oNlRshrZTg5WSyqHxrl+GaeTDPKlsjXuMmM=; b=iGsbpUy3uxhqU/Jnbc1e2Sx71hGJA3WId1ZphmkDbuAlSTY2P2a4eE9E6gD4e7ts7k/psF mdKbDfLEiIGoeOtqjP93tdVfalf6dHOJT+5xYGgRwzQGwibI/S7tFYCIwq8578Ri5YKkkg moKDNPPTUrQQiVNxLDen9BKuXv1PbyM= Received: from mail-qv1-f71.google.com (mail-qv1-f71.google.com [209.85.219.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-230-j-0xwC3zPj2lRwzI6ZAH5w-1; Mon, 24 Oct 2022 16:48:37 -0400 X-MC-Unique: j-0xwC3zPj2lRwzI6ZAH5w-1 Received: by mail-qv1-f71.google.com with SMTP id 71-20020a0c804d000000b004b2fb260447so5928547qva.10 for ; Mon, 24 Oct 2022 13:48:37 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=vZ6z2mx7oNlRshrZTg5WSyqHxrl+GaeTDPKlsjXuMmM=; b=5Pg3xtCiooULxLhOORsXpMVj9dVfHVHvpi8dHXDo54+fz8jOqKAkZW5nYFzFmhnvHZ OpoUakchyok87L23Yop+HCQ4X94Hortt+nusQDtw20vafVleaeuipNt6or67oQd01fzZ dbA5z4CgSpb7ouaLNHdXgLyMlHCygNWl7WyP10pIkwwoXlCZ+yj/nSlosbGZCZgsto7q UZ1SmFxThwa2fYmLc+qXW0D/7ihHLCOU+0yMMJNJOf4s2shtWE3F1bWVUakoCdUPP6g+ RxQKRcXrI1RP7rDcHzI0tlWk0zcjj8rvmUfIYgJ8CYQzoJ05T4gYQwLvZmA6s/gkrMDe NNhw== X-Gm-Message-State: ACrzQf1rSvfYvHCvrfUInB/oznK6L/HDNY0X5CgkBt/iSlPHRMuSRIvW JPQXEULsfo5rfz2lD2+VunAdU2j2G+qd9u7Ll5Unk6CN7hj0VptKWV23Sa/viI4dlq+QkvJBq7j 16eonSJK+aKCOTfsm7bHcIJCynGfzb6aT7AzI8sFNvowH51WVPOyGynE/8ZwMJT6S1gt+0F10MQ == X-Received: by 2002:a05:6214:b6c:b0:4bb:6747:3089 with SMTP id ey12-20020a0562140b6c00b004bb67473089mr7896759qvb.41.1666644516193; Mon, 24 Oct 2022 13:48:36 -0700 (PDT) X-Received: by 2002:a05:6214:b6c:b0:4bb:6747:3089 with SMTP id ey12-20020a0562140b6c00b004bb67473089mr7896733qvb.41.1666644515915; Mon, 24 Oct 2022 13:48:35 -0700 (PDT) Received: from x1n.redhat.com (bras-base-aurron9127w-grc-46-70-31-27-79.dsl.bell.ca. [70.31.27.79]) by smtp.gmail.com with ESMTPSA id d13-20020ac8544d000000b0038d9555b580sm498531qtq.44.2022.10.24.13.48.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Oct 2022 13:48:35 -0700 (PDT) From: Peter Xu To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Huang Ying , peterx@redhat.com, Andrew Morton , HORIGUCHI NAOYA , Miaohe Lin , David Hildenbrand , Andrea Arcangeli Subject: [PATCH RFC 2/2] mm: Use pte markers for swap errors Date: Mon, 24 Oct 2022 16:48:30 -0400 Message-Id: <20221024204830.1342169-3-peterx@redhat.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221024204830.1342169-1-peterx@redhat.com> References: <20221024204830.1342169-1-peterx@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2,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?1747610233344430544?= X-GMAIL-MSGID: =?utf-8?q?1747610233344430544?= PTE markers are ideal mechanism for things like SWP_SWAPIN_ERROR. Using a whole swap entry type for this purpose can be an overkill, especially if we already have PTE markers. Define a new bit for swapin error and replace it with pte markers. Then we can safely drop SWP_SWAPIN_ERROR and give one device slot back to swap. We used to have SWP_SWAPIN_ERROR taking the page pfn as part of the swap entry, but it's never used. Neither do I see how it can be useful because normally the swapin failure should not be caused by a bad page but bad swap device. Drop it alongside. Signed-off-by: Peter Xu Reviewed-by: Miaohe Lin --- include/linux/swap.h | 6 +----- include/linux/swapops.h | 26 ++++++++++++++------------ mm/memory.c | 6 ++++-- mm/shmem.c | 2 +- mm/swapfile.c | 2 +- 5 files changed, 21 insertions(+), 21 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index 211aeca9bfa7..fec6647a289a 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -55,10 +55,6 @@ static inline int current_is_kswapd(void) * actions on faults. */ -#define SWP_SWAPIN_ERROR_NUM 1 -#define SWP_SWAPIN_ERROR (MAX_SWAPFILES + SWP_HWPOISON_NUM + \ - SWP_MIGRATION_NUM + SWP_DEVICE_NUM + \ - SWP_PTE_MARKER_NUM) /* * PTE markers are used to persist information onto PTEs that otherwise * should be a none pte. As its name "PTE" hints, it should only be @@ -121,7 +117,7 @@ static inline int current_is_kswapd(void) #define MAX_SWAPFILES \ ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \ SWP_MIGRATION_NUM - SWP_HWPOISON_NUM - \ - SWP_PTE_MARKER_NUM - SWP_SWAPIN_ERROR_NUM) + SWP_PTE_MARKER_NUM) /* * Magic header for a swap area. The first part of the union is diff --git a/include/linux/swapops.h b/include/linux/swapops.h index 41a6e7b23415..dd087b7287b0 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -162,16 +162,6 @@ static inline void *swp_to_radix_entry(swp_entry_t entry) return xa_mk_value(entry.val); } -static inline swp_entry_t make_swapin_error_entry(struct page *page) -{ - return swp_entry(SWP_SWAPIN_ERROR, page_to_pfn(page)); -} - -static inline int is_swapin_error_entry(swp_entry_t entry) -{ - return swp_type(entry) == SWP_SWAPIN_ERROR; -} - #if IS_ENABLED(CONFIG_DEVICE_PRIVATE) static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset) { @@ -409,8 +399,9 @@ static inline bool is_migration_entry_dirty(swp_entry_t entry) typedef unsigned long pte_marker; -#define PTE_MARKER_UFFD_WP BIT(0) -#define PTE_MARKER_MASK (PTE_MARKER_UFFD_WP) +#define PTE_MARKER_UFFD_WP BIT(0) +#define PTE_MARKER_SWAP_ERROR BIT(1) +#define PTE_MARKER_MASK (BIT(2) - 1) static inline swp_entry_t make_pte_marker_entry(pte_marker marker) { @@ -437,6 +428,17 @@ static inline pte_t make_pte_marker(pte_marker marker) return swp_entry_to_pte(make_pte_marker_entry(marker)); } +static inline swp_entry_t make_swapin_error_entry(void) +{ + return make_pte_marker_entry(PTE_MARKER_SWAP_ERROR); +} + +static inline int is_swapin_error_entry(swp_entry_t entry) +{ + return is_pte_marker_entry(entry) && + (pte_marker_get(entry) & PTE_MARKER_SWAP_ERROR); +} + /* * This is a special version to check pte_none() just to cover the case when * the pte is a pte marker. It existed because in many cases the pte marker diff --git a/mm/memory.c b/mm/memory.c index 71114f05a68c..cf602c3854c3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3705,6 +3705,10 @@ static vm_fault_t handle_pte_marker(struct vm_fault *vmf) if (WARN_ON_ONCE(!marker)) return VM_FAULT_SIGBUS; + /* Higher priority than uffd-wp when data corrupted */ + if (marker & PTE_MARKER_SWAP_ERROR) + return VM_FAULT_SIGBUS; + if (pte_marker_entry_uffd_wp(entry)) return pte_marker_handle_uffd_wp(vmf); @@ -3764,8 +3768,6 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) put_page(vmf->page); } else if (is_hwpoison_entry(entry)) { ret = VM_FAULT_HWPOISON; - } else if (is_swapin_error_entry(entry)) { - ret = VM_FAULT_SIGBUS; } else if (is_pte_marker_entry(entry)) { ret = handle_pte_marker(vmf); } else { diff --git a/mm/shmem.c b/mm/shmem.c index c5f7a6668416..47dc595e98a3 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1682,7 +1682,7 @@ static void shmem_set_folio_swapin_error(struct inode *inode, pgoff_t index, swp_entry_t swapin_error; void *old; - swapin_error = make_swapin_error_entry(&folio->page); + swapin_error = make_swapin_error_entry(); old = xa_cmpxchg_irq(&mapping->i_pages, index, swp_to_radix_entry(swap), swp_to_radix_entry(swapin_error), 0); diff --git a/mm/swapfile.c b/mm/swapfile.c index 5fc1237a9f21..13f2569a6719 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1781,7 +1781,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, pte_t pteval; dec_mm_counter(vma->vm_mm, MM_SWAPENTS); - pteval = swp_entry_to_pte(make_swapin_error_entry(page)); + pteval = swp_entry_to_pte(make_swapin_error_entry()); set_pte_at(vma->vm_mm, addr, pte, pteval); swap_free(entry); ret = 0;