From patchwork Mon May 1 17:50:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suren Baghdasaryan X-Patchwork-Id: 89131 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:b0ea:0:b0:3b6:4342:cba0 with SMTP id b10csp90159vqo; Mon, 1 May 2023 10:55:42 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ5fj0H2I4MZXDs+ry0HrOhvy2Z8OWOMRzMzxLUw96joR7x/M00Qdu9OL0NgbdHpMPCfV3IN X-Received: by 2002:a05:6a00:a13:b0:63b:646d:9165 with SMTP id p19-20020a056a000a1300b0063b646d9165mr21595050pfh.26.1682963742335; Mon, 01 May 2023 10:55:42 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1682963742; cv=none; d=google.com; s=arc-20160816; b=h166ybFmHqJUFn9kIK483wRivMxz+SOfcNxfMaKv5a1Mnu3nZkBdYyvy/JXbNyoT32 d2O4IrJ9gM5Yo2VEJeFVZC8he/3k2HwnmSe/VYpKPHXnJcClYtNms0ugCuoA9TOXpI6V SbvhQd6ZGwSGGLYsqpa2h+fA7SBn0tD8fhPI/29Z+fUUEGWI4MiCoLIZSqn8c8ttN1nr uYoZPyj0T+6CET3lWrI+Do+BBrdVcmGhux6K7tFOvKK9mUzls7J6QX8godmEruHBKAAe XGO4Dsn3leR+49da2osNpDLhhr+44F0DVlvqkc8+uT2IdCD/WYIEu89VTu5tfctkAogU e26w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:mime-version:date :dkim-signature; bh=Vjmy9npoFS1ltTIQSU6SYKXLbdap9UrmwfWM+Y2ixPk=; b=Vy7foVnHyRCw+g9Mv5AUG6T2vqhTr/fbwEuhegihaMzCV+wfmOtnazPAXmXvp5L6tf pW522ij9SRqCrNnaQrWuo7/teW15w4kHAK+VxPgFI/XDNh7zPC9x6qALr7zEZ9XUYLdM NUaN0dtc0KIX0SlAMbg/i3L+8UUZgh7/SSgUsaTTMnS0+T4Z3ZCeftn1KxmgOBPq49uz MpIyK8yxWOD5MlQtvlTHxuLs4guk4WMO0O7h4XT0DFwyrevxYxd1Y3sfHag6JL3NoGTy twYMVEMpYX+RvQFKLjV6hcRWuzijuPwIah4a9FF38Yn/FvBvmpT/ja1tmA3C/fXvB0wM dIsA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b=dZCcwJnc; 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=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id a127-20020a621a85000000b0063b78126397si28108054pfa.230.2023.05.01.10.55.29; Mon, 01 May 2023 10:55:42 -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=@google.com header.s=20221208 header.b=dZCcwJnc; 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=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229871AbjEARue (ORCPT + 99 others); Mon, 1 May 2023 13:50:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230429AbjEARuc (ORCPT ); Mon, 1 May 2023 13:50:32 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 04ED910C6 for ; Mon, 1 May 2023 10:50:31 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-559d35837bbso54144037b3.3 for ; Mon, 01 May 2023 10:50:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1682963430; x=1685555430; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=Vjmy9npoFS1ltTIQSU6SYKXLbdap9UrmwfWM+Y2ixPk=; b=dZCcwJncaHug3B8HkBJA8I4rogyge1EVTo4b3P8k7VcTSJVpEkICoBGsnhmO7W+EaQ BIxtz97RUXIfYWYlU1CJsKlwqGVGZ7x+vS+3P/rfb8ANuZUjR7SbifV/F6aSBN5z7ZRt /AMQ4KNfWlhXtFlPUDhe7iDHC11AWgJzvh0HYI/QSVDj28sAvGrMcNoB1jrqM2PiCRxV MKWY+ho9Y/9MhG5dJ5YP+l84eWwLxXehtDV3C+sB45yhtiKFovPsBc0ojtZnWpwnmUO1 OgbB8QClj+k71UJXHVn/U9WcLkhMORsNKUzA9GKVhmcWDmrnB5+OYkqWUJRZdkLT90UK DpmA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1682963430; x=1685555430; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=Vjmy9npoFS1ltTIQSU6SYKXLbdap9UrmwfWM+Y2ixPk=; b=BsilZOOoLlkgaf5L8TRwYqLod7zmE88nRCfmPpYLrDiEB+xbxtKui2Rhvn84eE052T pOe6yBSzTCfniX9Gns3SQgvqqou0xpD8rjxFiBCmG2CMEr6twTt3Lgt0TJPQL+cNe7Xm imTpxXSg1PSGoLZ+djL/MfIMjMQOrlp5lxQxIoSFXKGTw25o9+xWOGaSdpOzxIImMvBZ qsPp8xz93J+798z2ruU7+roaDzl2mwl+fx782e0+4eZKTA44FBI7Og2hESkzv9kJ/lBV Q0jFN3rdZ9HLNQqLhfcVEOxi6Nudz2JVjMRjAkFWJEqmte1OOvT1WvRBh7OWBfmYCGAx 8vkQ== X-Gm-Message-State: AC+VfDy69IhJ9RyvZmrqrmWx6lT4npRUZeUxIWvKNHS4mS3nd+54/ce0 55Gt05d3yaSr3L7D6OdzqsDPvKWzYh0= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:201:6d24:3efd:facc:7ac4]) (user=surenb job=sendgmr) by 2002:a81:9f09:0:b0:559:e830:60f1 with SMTP id s9-20020a819f09000000b00559e83060f1mr4687408ywn.8.1682963430249; Mon, 01 May 2023 10:50:30 -0700 (PDT) Date: Mon, 1 May 2023 10:50:23 -0700 Mime-Version: 1.0 X-Mailer: git-send-email 2.40.1.495.gc816e09b53d-goog Message-ID: <20230501175025.36233-1-surenb@google.com> Subject: [PATCH 1/3] mm: handle swap page faults under VMA lock if page is uncontended From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: willy@infradead.org, hannes@cmpxchg.org, mhocko@suse.com, josef@toxicpanda.com, jack@suse.cz, ldufour@linux.ibm.com, laurent.dufour@fr.ibm.com, michel@lespinasse.org, liam.howlett@oracle.com, jglisse@google.com, vbabka@suse.cz, minchan@google.com, dave@stgolabs.net, punit.agrawal@bytedance.com, lstoakes@gmail.com, hdanton@sina.com, apopple@nvidia.com, surenb@google.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,USER_IN_DEF_DKIM_WL autolearn=unavailable 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?1764715389330672741?= X-GMAIL-MSGID: =?utf-8?q?1764715389330672741?= When page fault is handled under VMA lock protection, all swap page faults are retried with mmap_lock because folio_lock_or_retry implementation has to drop and reacquire mmap_lock if folio could not be immediately locked. Instead of retrying all swapped page faults, retry only when folio locking fails. Drivers implementing ops->migrate_to_ram might still rely on mmap_lock, therefore fall back to mmap_lock in this case. Signed-off-by: Suren Baghdasaryan --- mm/filemap.c | 6 ++++++ mm/memory.c | 14 +++++++++----- 2 files changed, 15 insertions(+), 5 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index a34abfe8c654..84f39114d4de 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1706,6 +1706,8 @@ static int __folio_lock_async(struct folio *folio, struct wait_page_queue *wait) * mmap_lock has been released (mmap_read_unlock(), unless flags had both * FAULT_FLAG_ALLOW_RETRY and FAULT_FLAG_RETRY_NOWAIT set, in * which case mmap_lock is still held. + * If flags had FAULT_FLAG_VMA_LOCK set, meaning the operation is performed + * with VMA lock only, the VMA lock is still held. * * If neither ALLOW_RETRY nor KILLABLE are set, will always return true * with the folio locked and the mmap_lock unperturbed. @@ -1713,6 +1715,10 @@ static int __folio_lock_async(struct folio *folio, struct wait_page_queue *wait) bool __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm, unsigned int flags) { + /* Can't do this if not holding mmap_lock */ + if (flags & FAULT_FLAG_VMA_LOCK) + return false; + if (fault_flag_allow_retry_first(flags)) { /* * CAUTION! In this case, mmap_lock is not released diff --git a/mm/memory.c b/mm/memory.c index f69fbc251198..41f45819a923 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3711,11 +3711,6 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) if (!pte_unmap_same(vmf)) goto out; - if (vmf->flags & FAULT_FLAG_VMA_LOCK) { - ret = VM_FAULT_RETRY; - goto out; - } - entry = pte_to_swp_entry(vmf->orig_pte); if (unlikely(non_swap_entry(entry))) { if (is_migration_entry(entry)) { @@ -3725,6 +3720,15 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) vmf->page = pfn_swap_entry_to_page(entry); ret = remove_device_exclusive_entry(vmf); } else if (is_device_private_entry(entry)) { + if (vmf->flags & FAULT_FLAG_VMA_LOCK) { + /* + * migrate_to_ram is not yet ready to operate + * under VMA lock. + */ + ret |= VM_FAULT_RETRY; + goto out; + } + vmf->page = pfn_swap_entry_to_page(entry); vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, &vmf->ptl); From patchwork Mon May 1 17:50:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suren Baghdasaryan X-Patchwork-Id: 89134 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:b0ea:0:b0:3b6:4342:cba0 with SMTP id b10csp95068vqo; Mon, 1 May 2023 11:03:41 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ7lE6onHOmDhF4yCFgKRDa0Tzw8ERRBM5jEKZY+0vZI4XZUEMDAIHS7fA7/XLAHjT69qU4l X-Received: by 2002:a05:6a20:7f90:b0:ee:786b:d6f8 with SMTP id d16-20020a056a207f9000b000ee786bd6f8mr18328291pzj.57.1682964221210; Mon, 01 May 2023 11:03:41 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1682964221; cv=none; d=google.com; s=arc-20160816; b=Dt+0o/rDy4ccq7ul15I5lmXsPh75XG8KshD03QcUC+/euzEiJaKT0OsNzJ7CNK9pKR viEVRe9ThsIMj/v2kWWtTJUlowFBXWZZg/hC9wa9Q9MXfYKD7/+O+1hnP1Rn2LnertGx X+syM67hkTSTWnvw6MeqqgnLTqW+YGRy7pj+RQl6GHttnP/To9+g0qB7Na2Y2831PUTB VFRbYk9rkF3lvZRoGODkszKfB7eGwoacHnKsqhCFQbwPzzRSdjjmqzd3beNz0E54WnS1 lCi33oai44Aqf6oqID7cbpXAA/VXV3NQ16ubkWZmDcNko/gN5I9xY9t+rHrRIEFNYTMb lT3g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:dkim-signature; bh=Vw7vchvPa5zb0i4uc6VlbyjDM+/1CtZDGIGJ1EuR9xw=; b=irzv4Ij6kkJ2jge1CBwd+rGZ0/Sqckxw8pTWg+HqQE7/ko2shV3vQnx7A6NKpdPCR+ j3RQJ8P8J8/NicQZ/VkFMJBekdJBvXJ13L7vwcHS8ocsQfBbt2cHqDFFCNxemnSZYt95 ac4NP/FXo7ADo0qqGgHpNb4T07DFsCAG2M5U5oQrAGavO/akWqKMb6CJfP50oG/4DlSV Gy804vTWJK6a53KRQq1wqKQFygGWe0QzRb8SGwmGrzRBMX1ZlNFZBVW7E1Hsw2cAI5W2 xei3t0+0UiGL0D5rfrASzYTm4aGzThxqtBnZpbqn1StAIM3Psm9UTE/essKCq9nPRYe9 RueQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b=5HsHeOLj; 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=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (out1.vger.email. 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Introduce VM_FAULT_VMA_UNLOCKED to indicate that VMA lock was dropped while in handle_mm_fault(). Note that once VMA lock is dropped, the VMA reference can't be used as there are no guarantees it was not freed. Signed-off-by: Suren Baghdasaryan --- arch/arm64/mm/fault.c | 3 ++- arch/powerpc/mm/fault.c | 3 ++- arch/s390/mm/fault.c | 3 ++- arch/x86/mm/fault.c | 3 ++- include/linux/mm_types.h | 6 +++++- mm/memory.c | 12 ++++++++++-- 6 files changed, 23 insertions(+), 7 deletions(-) diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 9e0db5c387e3..8fa281f49d61 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -602,7 +602,8 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr, } fault = handle_mm_fault(vma, addr & PAGE_MASK, mm_flags | FAULT_FLAG_VMA_LOCK, regs); - vma_end_read(vma); + if (!(fault & VM_FAULT_VMA_UNLOCKED)) + vma_end_read(vma); if (!(fault & VM_FAULT_RETRY)) { count_vm_vma_lock_event(VMA_LOCK_SUCCESS); diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 531177a4ee08..b27730f07141 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -494,7 +494,8 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address, } fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs); - vma_end_read(vma); + if (!(fault & VM_FAULT_VMA_UNLOCKED)) + vma_end_read(vma); if (!(fault & VM_FAULT_RETRY)) { count_vm_vma_lock_event(VMA_LOCK_SUCCESS); diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index b65144c392b0..cc923dbb0821 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -418,7 +418,8 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) goto lock_mmap; } fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs); - vma_end_read(vma); + if (!(fault & VM_FAULT_VMA_UNLOCKED)) + vma_end_read(vma); if (!(fault & VM_FAULT_RETRY)) { count_vm_vma_lock_event(VMA_LOCK_SUCCESS); goto out; diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index e4399983c50c..ef62ab2fd211 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1347,7 +1347,8 @@ void do_user_addr_fault(struct pt_regs *regs, goto lock_mmap; } fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs); - vma_end_read(vma); + if (!(fault & VM_FAULT_VMA_UNLOCKED)) + vma_end_read(vma); if (!(fault & VM_FAULT_RETRY)) { count_vm_vma_lock_event(VMA_LOCK_SUCCESS); diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 306a3d1a0fa6..b3b57c6da0e1 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -1030,6 +1030,7 @@ typedef __bitwise unsigned int vm_fault_t; * fsync() to complete (for synchronous page faults * in DAX) * @VM_FAULT_COMPLETED: ->fault completed, meanwhile mmap lock released + * @VM_FAULT_VMA_UNLOCKED: VMA lock was released * @VM_FAULT_HINDEX_MASK: mask HINDEX value * */ @@ -1047,6 +1048,7 @@ enum vm_fault_reason { VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000, VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000, VM_FAULT_COMPLETED = (__force vm_fault_t)0x004000, + VM_FAULT_VMA_UNLOCKED = (__force vm_fault_t)0x008000, VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000, }; @@ -1070,7 +1072,9 @@ enum vm_fault_reason { { VM_FAULT_RETRY, "RETRY" }, \ { VM_FAULT_FALLBACK, "FALLBACK" }, \ { VM_FAULT_DONE_COW, "DONE_COW" }, \ - { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" } + { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" }, \ + { VM_FAULT_COMPLETED, "COMPLETED" }, \ + { VM_FAULT_VMA_UNLOCKED, "VMA_UNLOCKED" } struct vm_special_mapping { const char *name; /* The name, e.g. "[vdso]". */ diff --git a/mm/memory.c b/mm/memory.c index 41f45819a923..8222acf74fd3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3714,8 +3714,16 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) entry = pte_to_swp_entry(vmf->orig_pte); if (unlikely(non_swap_entry(entry))) { if (is_migration_entry(entry)) { - migration_entry_wait(vma->vm_mm, vmf->pmd, - vmf->address); + /* Save mm in case VMA lock is dropped */ + struct mm_struct *mm = vma->vm_mm; + + if (vmf->flags & FAULT_FLAG_VMA_LOCK) { + /* No need to hold VMA lock for migration */ + vma_end_read(vma); + /* CAUTION! VMA can't be used after this */ + ret |= VM_FAULT_VMA_UNLOCKED; + } + migration_entry_wait(mm, vmf->pmd, vmf->address); } else if (is_device_exclusive_entry(entry)) { vmf->page = pfn_swap_entry_to_page(entry); ret = remove_device_exclusive_entry(vmf); From patchwork Mon May 1 17:50:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suren Baghdasaryan X-Patchwork-Id: 89133 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:b0ea:0:b0:3b6:4342:cba0 with SMTP id b10csp95027vqo; Mon, 1 May 2023 11:03:38 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ7cFkpcSUkUhL6pcJfXEBV7vS+aAo5GXoHhWt7N9uGosfRLbj1cbvtzu+LuAQlGQN6SczWR X-Received: by 2002:a17:902:d512:b0:1aa:d971:4623 with SMTP id b18-20020a170902d51200b001aad9714623mr8633861plg.38.1682964218589; Mon, 01 May 2023 11:03:38 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1682964218; cv=none; d=google.com; s=arc-20160816; b=pJ1ebMdDNVDVXfxkqoi9AuQU4CWV6aDylQQ+ms3WcMJkRLEcB9e8ZbXdWurpiuUg// xmIoDZf+/jxSukNGpfDm2gtiQlPCl6i9368UivPfEHK/XxPKY53pQhc8hp5ISloTCIKc k3YEOj2mIh7vpYK6JwbXv7ahfmhTQg+I0HZUcU1nGirMlKsJ94bhjhZh3I5rLZ594gdO ZATpqTnIVf2rfC83Hp1A+Y7J3/fK9SAujOsA/JkQ53ztKrnvfWU1ipizr7vJryGGEva+ LBs9UADS2sdlhX0oWpSF8KUbLueSJo6AkHutrX+f9K6z8Ld5WrhT+RsDiKAgVrYce8Of bbRg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:dkim-signature; bh=oNrjh4NDZfCOCA+XspYc7I9kB51AWPXlbM0N3pX4I38=; b=AA9/pKdyLTLF3jeQBJlJwLd02TCUb3UjeEb1+57pf5uk3sD3NIhyJrMvDfg3LqirM4 0imXoDSOFTGDc8ygZJR6rFtPb7IrS5cJVCxMkTqVDQ+hK51NtN+aNwl/nkGNNXc8krJc 8TZy6wjnzTEotUQJgGp6KMkdThNw1Dj0/oofTcmbvg0GX06fjKLmMtvXyYYCY4cXWxnf wcwukKxk2iqe9Mzdyz9VUMSRScmqZdMsItk2UIyJNYyeC5zeOP3f57ho2gA9g9HFjSgJ TtkIPs8uVYJtjmy1SQ9krWT48TnDTi56lRJ+vVohE7oyLkO/FhF2Zg/ThBuvvYfK6OAx iY+g== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b=Kbw2vWgf; 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=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (out1.vger.email. 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Signed-off-by: Suren Baghdasaryan --- include/linux/pagemap.h | 14 ++++++++++---- mm/filemap.c | 43 ++++++++++++++++++++++------------------- mm/memory.c | 13 +++++++++---- 3 files changed, 42 insertions(+), 28 deletions(-) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index a56308a9d1a4..6c9493314c21 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -896,8 +896,8 @@ static inline bool wake_page_match(struct wait_page_queue *wait_page, void __folio_lock(struct folio *folio); int __folio_lock_killable(struct folio *folio); -bool __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm, - unsigned int flags); +bool __folio_lock_or_retry(struct folio *folio, struct vm_area_struct *vma, + unsigned int flags, bool *lock_dropped); void unlock_page(struct page *page); void folio_unlock(struct folio *folio); @@ -1002,10 +1002,16 @@ static inline int folio_lock_killable(struct folio *folio) * __folio_lock_or_retry(). */ static inline bool folio_lock_or_retry(struct folio *folio, - struct mm_struct *mm, unsigned int flags) + struct vm_area_struct *vma, unsigned int flags, + bool *lock_dropped) { might_sleep(); - return folio_trylock(folio) || __folio_lock_or_retry(folio, mm, flags); + if (folio_trylock(folio)) { + *lock_dropped = false; + return true; + } + + return __folio_lock_or_retry(folio, vma, flags, lock_dropped); } /* diff --git a/mm/filemap.c b/mm/filemap.c index 84f39114d4de..9c0fa8578b2f 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1701,37 +1701,35 @@ static int __folio_lock_async(struct folio *folio, struct wait_page_queue *wait) /* * Return values: - * true - folio is locked; mmap_lock is still held. + * true - folio is locked. * false - folio is not locked. - * mmap_lock has been released (mmap_read_unlock(), unless flags had both - * FAULT_FLAG_ALLOW_RETRY and FAULT_FLAG_RETRY_NOWAIT set, in - * which case mmap_lock is still held. - * If flags had FAULT_FLAG_VMA_LOCK set, meaning the operation is performed - * with VMA lock only, the VMA lock is still held. + * + * lock_dropped indicates whether mmap_lock/VMA lock got dropped. + * mmap_lock/VMA lock is dropped when function fails to lock the folio, + * unless flags had both FAULT_FLAG_ALLOW_RETRY and FAULT_FLAG_RETRY_NOWAIT + * set, in which case mmap_lock/VMA lock is still held. * * If neither ALLOW_RETRY nor KILLABLE are set, will always return true - * with the folio locked and the mmap_lock unperturbed. + * with the folio locked and the mmap_lock/VMA lock unperturbed. */ -bool __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm, - unsigned int flags) +bool __folio_lock_or_retry(struct folio *folio, struct vm_area_struct *vma, + unsigned int flags, bool *lock_dropped) { - /* Can't do this if not holding mmap_lock */ - if (flags & FAULT_FLAG_VMA_LOCK) - return false; - if (fault_flag_allow_retry_first(flags)) { - /* - * CAUTION! In this case, mmap_lock is not released - * even though return 0. - */ - if (flags & FAULT_FLAG_RETRY_NOWAIT) + if (flags & FAULT_FLAG_RETRY_NOWAIT) { + *lock_dropped = false; return false; + } - mmap_read_unlock(mm); + if (flags & FAULT_FLAG_VMA_LOCK) + vma_end_read(vma); + else + mmap_read_unlock(vma->vm_mm); if (flags & FAULT_FLAG_KILLABLE) folio_wait_locked_killable(folio); else folio_wait_locked(folio); + *lock_dropped = true; return false; } if (flags & FAULT_FLAG_KILLABLE) { @@ -1739,13 +1737,18 @@ bool __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm, ret = __folio_lock_killable(folio); if (ret) { - mmap_read_unlock(mm); + if (flags & FAULT_FLAG_VMA_LOCK) + vma_end_read(vma); + else + mmap_read_unlock(vma->vm_mm); + *lock_dropped = true; return false; } } else { __folio_lock(folio); } + *lock_dropped = false; return true; } diff --git a/mm/memory.c b/mm/memory.c index 8222acf74fd3..e1cd39f00756 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3568,6 +3568,7 @@ static vm_fault_t remove_device_exclusive_entry(struct vm_fault *vmf) struct folio *folio = page_folio(vmf->page); struct vm_area_struct *vma = vmf->vma; struct mmu_notifier_range range; + bool lock_dropped; /* * We need a reference to lock the folio because we don't hold @@ -3580,8 +3581,10 @@ static vm_fault_t remove_device_exclusive_entry(struct vm_fault *vmf) if (!folio_try_get(folio)) return 0; - if (!folio_lock_or_retry(folio, vma->vm_mm, vmf->flags)) { + if (!folio_lock_or_retry(folio, vma, vmf->flags, &lock_dropped)) { folio_put(folio); + if (lock_dropped && vmf->flags & FAULT_FLAG_VMA_LOCK) + return VM_FAULT_VMA_UNLOCKED | VM_FAULT_RETRY; return VM_FAULT_RETRY; } mmu_notifier_range_init_owner(&range, MMU_NOTIFY_EXCLUSIVE, 0, @@ -3704,7 +3707,8 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) bool exclusive = false; swp_entry_t entry; pte_t pte; - int locked; + bool locked; + bool lock_dropped; vm_fault_t ret = 0; void *shadow = NULL; @@ -3837,9 +3841,10 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) goto out_release; } - locked = folio_lock_or_retry(folio, vma->vm_mm, vmf->flags); - + locked = folio_lock_or_retry(folio, vma, vmf->flags, &lock_dropped); if (!locked) { + if (lock_dropped && vmf->flags & FAULT_FLAG_VMA_LOCK) + ret |= VM_FAULT_VMA_UNLOCKED; ret |= VM_FAULT_RETRY; goto out_release; }