From patchwork Thu Sep 5 10:15:28 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 11132627 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CBC931805 for ; Thu, 5 Sep 2019 10:16:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 87FDF2184B for ; Thu, 5 Sep 2019 10:16:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 87FDF2184B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 8AEAC6B027A; Thu, 5 Sep 2019 06:15:59 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 85E3A6B027B; Thu, 5 Sep 2019 06:15:59 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 773526B027C; Thu, 5 Sep 2019 06:15:59 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0055.hostedemail.com [216.40.44.55]) by kanga.kvack.org (Postfix) with ESMTP id 540B06B027A for ; Thu, 5 Sep 2019 06:15:59 -0400 (EDT) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id 016F1180AD7C3 for ; Thu, 5 Sep 2019 10:15:59 +0000 (UTC) X-FDA: 75900461238.14.plant36_5137a00cc5331 X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,peterx@redhat.com,::linux-kernel@vger.kernel.org:david@redhat.com:hughd@google.com:gokhale2@llnl.gov:jglisse@redhat.com:xemul@virtuozzo.com:hannes@cmpxchg.org:peterx@redhat.com:cracauer@cons.org:mcfadden8@llnl.gov:shli@fb.com:aarcange@redhat.com:mike.kravetz@oracle.com:dplotnikov@virtuozzo.com:rppt@linux.vnet.ibm.com:torvalds@linux-foundation.org:mgorman@suse.de:kirill@shutemov.name:dgilbert@redhat.com,RULES_HIT:30003:30029:30034:30054:30070:30090,0,RBL:209.132.183.28:@redhat.com:.lbl8.mailshell.net-62.18.0.0 64.10.201.10,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:ft,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:25,LUA_SUMMARY:none X-HE-Tag: plant36_5137a00cc5331 X-Filterd-Recvd-Size: 11148 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by imf41.hostedemail.com (Postfix) with ESMTP for ; Thu, 5 Sep 2019 10:15:57 +0000 (UTC) Received: from mail-pf1-f198.google.com (mail-pf1-f198.google.com [209.85.210.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 040B2882EA for ; Thu, 5 Sep 2019 10:15:57 +0000 (UTC) Received: by mail-pf1-f198.google.com with SMTP id x10so1453166pfr.20 for ; Thu, 05 Sep 2019 03:15:56 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=U6jD3QrhOaKmK0EuyaVvKU+JdqlKP+u0W9Mccju17fc=; b=htfhj+IYscmbxxY0SLCs9w0cqqV1R+sCOSKOxI5eAz0TtrVCZIBUl6yjunodMzqWGO RyJCv7K3KGt+GrZu5Q11rMiSuUgji3wX2phLJJ0Uq2wIe/Yl1BDeuUuqEHgTClW7GeNK Z6TjxCknu30+/EK+tpXJlD5aThK1iFGR+kvdC+MsB3lf3QhW5VXyqstcEYd9IyCzrGc6 6AW75jgG64X0tqDBF7Ie2+EaUQFSItalI2Qi31r/8O0o5C2u9GdoTmNaA7BxSELhf4o8 mBIHkLhstEw1F6IuWHtiHLdlJKXtMOBsMcafpGFjmnJnSKo6tKruXQviNbZKjBiwtcGR oOfQ== X-Gm-Message-State: APjAAAWlMNFjTm/967u9YqXqw7DASO/MteDxy7z+EIUDjR9Yxh2RGvha zKczvCBPyJwz64VNs6jpPybKxa+BmTqZgZuyqMWGoRqkhtHNNJdS0DyNDxQbvc8HLVQxvpqUd1H Tr55bDGHUV9w= X-Received: by 2002:a62:ee0e:: with SMTP id e14mr2873486pfi.31.1567678556101; Thu, 05 Sep 2019 03:15:56 -0700 (PDT) X-Google-Smtp-Source: APXvYqxLZrMDTh45FeN+eUEDYn/HUog7bmtWQpvM3Fo3USpydbbe3iJMJ/OqTwL2izDvJ0YR0cnVLQ== X-Received: by 2002:a62:ee0e:: with SMTP id e14mr2873454pfi.31.1567678555825; Thu, 05 Sep 2019 03:15:55 -0700 (PDT) Received: from xz-x1.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id a20sm413852pfo.33.2019.09.05.03.15.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Sep 2019 03:15:55 -0700 (PDT) From: Peter Xu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: David Hildenbrand , Hugh Dickins , Maya Gokhale , Jerome Glisse , Pavel Emelyanov , Johannes Weiner , peterx@redhat.com, Martin Cracauer , Marty McFadden , Shaohua Li , Andrea Arcangeli , Mike Kravetz , Denis Plotnikov , Mike Rapoport , Linus Torvalds , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" Subject: [PATCH v2 1/7] mm/gup: Rename "nonblocking" to "locked" where proper Date: Thu, 5 Sep 2019 18:15:28 +0800 Message-Id: <20190905101534.9637-2-peterx@redhat.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190905101534.9637-1-peterx@redhat.com> References: <20190905101534.9637-1-peterx@redhat.com> MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: There's plenty of places around __get_user_pages() that has a parameter "nonblocking" which does not really mean that "it won't block" (because it can really block) but instead it shows whether the mmap_sem is released by up_read() during the page fault handling mostly when VM_FAULT_RETRY is returned. We have the correct naming in e.g. get_user_pages_locked() or get_user_pages_remote() as "locked", however there're still many places that are using the "nonblocking" as name. Renaming the places to "locked" where proper to better suite the functionality of the variable. While at it, fixing up some of the comments accordingly. Reviewed-by: Mike Rapoport Reviewed-by: Jerome Glisse Signed-off-by: Peter Xu Reviewed-by: David Hildenbrand --- mm/gup.c | 44 +++++++++++++++++++++----------------------- mm/hugetlb.c | 8 ++++---- 2 files changed, 25 insertions(+), 27 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 98f13ab37bac..eddbb95dcb8f 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -622,12 +622,12 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address, } /* - * mmap_sem must be held on entry. If @nonblocking != NULL and - * *@flags does not include FOLL_NOWAIT, the mmap_sem may be released. - * If it is, *@nonblocking will be set to 0 and -EBUSY returned. + * mmap_sem must be held on entry. If @locked != NULL and *@flags + * does not include FOLL_NOWAIT, the mmap_sem may be released. If it + * is, *@locked will be set to 0 and -EBUSY returned. */ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma, - unsigned long address, unsigned int *flags, int *nonblocking) + unsigned long address, unsigned int *flags, int *locked) { unsigned int fault_flags = 0; vm_fault_t ret; @@ -639,7 +639,7 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma, fault_flags |= FAULT_FLAG_WRITE; if (*flags & FOLL_REMOTE) fault_flags |= FAULT_FLAG_REMOTE; - if (nonblocking) + if (locked) fault_flags |= FAULT_FLAG_ALLOW_RETRY; if (*flags & FOLL_NOWAIT) fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT; @@ -665,8 +665,8 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma, } if (ret & VM_FAULT_RETRY) { - if (nonblocking && !(fault_flags & FAULT_FLAG_RETRY_NOWAIT)) - *nonblocking = 0; + if (locked && !(fault_flags & FAULT_FLAG_RETRY_NOWAIT)) + *locked = 0; return -EBUSY; } @@ -743,7 +743,7 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) * only intends to ensure the pages are faulted in. * @vmas: array of pointers to vmas corresponding to each page. * Or NULL if the caller does not require them. - * @nonblocking: whether waiting for disk IO or mmap_sem contention + * @locked: whether we're still with the mmap_sem held * * Returns number of pages pinned. This may be fewer than the number * requested. If nr_pages is 0 or negative, returns 0. If no pages @@ -772,13 +772,11 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) * appropriate) must be called after the page is finished with, and * before put_page is called. * - * If @nonblocking != NULL, __get_user_pages will not wait for disk IO - * or mmap_sem contention, and if waiting is needed to pin all pages, - * *@nonblocking will be set to 0. Further, if @gup_flags does not - * include FOLL_NOWAIT, the mmap_sem will be released via up_read() in - * this case. + * If @locked != NULL, *@locked will be set to 0 when mmap_sem is + * released by an up_read(). That can happen if @gup_flags does not + * have FOLL_NOWAIT. * - * A caller using such a combination of @nonblocking and @gup_flags + * A caller using such a combination of @locked and @gup_flags * must therefore hold the mmap_sem for reading only, and recognize * when it's been released. Otherwise, it must be held for either * reading or writing and will not be released. @@ -790,7 +788,7 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, - struct vm_area_struct **vmas, int *nonblocking) + struct vm_area_struct **vmas, int *locked) { long ret = 0, i = 0; struct vm_area_struct *vma = NULL; @@ -834,7 +832,7 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, if (is_vm_hugetlb_page(vma)) { i = follow_hugetlb_page(mm, vma, pages, vmas, &start, &nr_pages, i, - gup_flags, nonblocking); + gup_flags, locked); continue; } } @@ -852,7 +850,7 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, page = follow_page_mask(vma, start, foll_flags, &ctx); if (!page) { ret = faultin_page(tsk, vma, start, &foll_flags, - nonblocking); + locked); switch (ret) { case 0: goto retry; @@ -1178,7 +1176,7 @@ EXPORT_SYMBOL(get_user_pages_remote); * @vma: target vma * @start: start address * @end: end address - * @nonblocking: + * @locked: whether the mmap_sem is still held * * This takes care of mlocking the pages too if VM_LOCKED is set. * @@ -1186,14 +1184,14 @@ EXPORT_SYMBOL(get_user_pages_remote); * * vma->vm_mm->mmap_sem must be held. * - * If @nonblocking is NULL, it may be held for read or write and will + * If @locked is NULL, it may be held for read or write and will * be unperturbed. * - * If @nonblocking is non-NULL, it must held for read only and may be - * released. If it's released, *@nonblocking will be set to 0. + * If @locked is non-NULL, it must held for read only and may be + * released. If it's released, *@locked will be set to 0. */ long populate_vma_page_range(struct vm_area_struct *vma, - unsigned long start, unsigned long end, int *nonblocking) + unsigned long start, unsigned long end, int *locked) { struct mm_struct *mm = vma->vm_mm; unsigned long nr_pages = (end - start) / PAGE_SIZE; @@ -1228,7 +1226,7 @@ long populate_vma_page_range(struct vm_area_struct *vma, * not result in a stack expansion that recurses back here. */ return __get_user_pages(current, mm, start, nr_pages, gup_flags, - NULL, NULL, nonblocking); + NULL, NULL, locked); } /* diff --git a/mm/hugetlb.c b/mm/hugetlb.c index ede7e7f5d1ab..5f816ee42206 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4251,7 +4251,7 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, struct page **pages, struct vm_area_struct **vmas, unsigned long *position, unsigned long *nr_pages, - long i, unsigned int flags, int *nonblocking) + long i, unsigned int flags, int *locked) { unsigned long pfn_offset; unsigned long vaddr = *position; @@ -4322,7 +4322,7 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, spin_unlock(ptl); if (flags & FOLL_WRITE) fault_flags |= FAULT_FLAG_WRITE; - if (nonblocking) + if (locked) fault_flags |= FAULT_FLAG_ALLOW_RETRY; if (flags & FOLL_NOWAIT) fault_flags |= FAULT_FLAG_ALLOW_RETRY | @@ -4339,9 +4339,9 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, break; } if (ret & VM_FAULT_RETRY) { - if (nonblocking && + if (locked && !(fault_flags & FAULT_FLAG_RETRY_NOWAIT)) - *nonblocking = 0; + *locked = 0; *nr_pages = 0; /* * VM_FAULT_RETRY must not return an From patchwork Thu Sep 5 10:15:29 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 11132629 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 20C8D1805 for ; Thu, 5 Sep 2019 10:16:08 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D156F21883 for ; Thu, 5 Sep 2019 10:16:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D156F21883 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E04146B027B; Thu, 5 Sep 2019 06:16:06 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id DB8466B027C; Thu, 5 Sep 2019 06:16:06 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CA59F6B027D; Thu, 5 Sep 2019 06:16:06 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0239.hostedemail.com [216.40.44.239]) by kanga.kvack.org (Postfix) with ESMTP id A11686B027B for ; Thu, 5 Sep 2019 06:16:06 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id F2B0D21EA for ; Thu, 5 Sep 2019 10:16:05 +0000 (UTC) X-FDA: 75900461490.09.house74_5247d51e2ac0a X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,peterx@redhat.com,::linux-kernel@vger.kernel.org:david@redhat.com:hughd@google.com:gokhale2@llnl.gov:jglisse@redhat.com:xemul@virtuozzo.com:hannes@cmpxchg.org:peterx@redhat.com:cracauer@cons.org:mcfadden8@llnl.gov:shli@fb.com:aarcange@redhat.com:mike.kravetz@oracle.com:dplotnikov@virtuozzo.com:rppt@linux.vnet.ibm.com:torvalds@linux-foundation.org:mgorman@suse.de:kirill@shutemov.name:dgilbert@redhat.com,RULES_HIT:30003:30012:30051:30054,0,RBL:209.132.183.28:@redhat.com:.lbl8.mailshell.net-62.18.0.0 64.10.201.10,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:ft,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:28,LUA_SUMMARY:none X-HE-Tag: house74_5247d51e2ac0a X-Filterd-Recvd-Size: 17125 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by imf07.hostedemail.com (Postfix) with ESMTP for ; Thu, 5 Sep 2019 10:16:05 +0000 (UTC) Received: from mail-pg1-f197.google.com (mail-pg1-f197.google.com [209.85.215.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8EDE42A09D4 for ; Thu, 5 Sep 2019 10:16:04 +0000 (UTC) Received: by mail-pg1-f197.google.com with SMTP id e20so1046910pgt.22 for ; Thu, 05 Sep 2019 03:16:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=iMX6s7oeTnBzBZ0zA0kNaUvnXYwB9KFfx/CrFTaSGBQ=; b=MgR8qcmCN/IMmuCkj/qcSyLQhJoD2DLNKEmJGpMJlNFP6XWocnVgqIpGt/76Cj0rxb ZaqQOzgmgP9BXYGUzedCHu6Y8ycnGrJOlz4ULH827zCqgx2fxvKtxPdxuUG0OpGF9mUz 4z4dTlYYsGeFNTDwi7/JPyr1FS4POrliQIqWCyLc4Pc/5RtwqvHVBpW7IKIa1RGh19jp iPXDiYPd7A3xFz7rF64QuNdCyKGzjdpOpI3YdY0AU/9aeYulKUd0yU8yurdEotweYmFe Mi+e/BlfPPpY52as9FHE41wsAIkDPAfik8sjl2p0uJyQOFWl3/K0f3VraVcfFrBrIzih llEA== X-Gm-Message-State: APjAAAVoCUnT65unjIuxTKPECEZsQUq+uLaROzumwnAzxVaJYZQqVyZt YJLsfWKzf6vRynBNKp6msoI+OMxPLsjRhSiG5ORTimQRH4Klz+yP+C/o6HmWRXgFRoQdfAas5Gq zX2EhNzW+jIE= X-Received: by 2002:a62:2ac4:: with SMTP id q187mr2756398pfq.242.1567678563394; Thu, 05 Sep 2019 03:16:03 -0700 (PDT) X-Google-Smtp-Source: APXvYqyK238bn3DlfGpKaLHvH7uK39heRDkCDTdIqTCq8iMKx9YlL0fNL0Th6egAE0DovW2vcv3nzA== X-Received: by 2002:a62:2ac4:: with SMTP id q187mr2756355pfq.242.1567678563032; Thu, 05 Sep 2019 03:16:03 -0700 (PDT) Received: from xz-x1.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id a20sm413852pfo.33.2019.09.05.03.15.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Sep 2019 03:16:02 -0700 (PDT) From: Peter Xu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: David Hildenbrand , Hugh Dickins , Maya Gokhale , Jerome Glisse , Pavel Emelyanov , Johannes Weiner , peterx@redhat.com, Martin Cracauer , Marty McFadden , Shaohua Li , Andrea Arcangeli , Mike Kravetz , Denis Plotnikov , Mike Rapoport , Linus Torvalds , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" Subject: [PATCH v2 2/7] mm: Introduce FAULT_FLAG_DEFAULT Date: Thu, 5 Sep 2019 18:15:29 +0800 Message-Id: <20190905101534.9637-3-peterx@redhat.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190905101534.9637-1-peterx@redhat.com> References: <20190905101534.9637-1-peterx@redhat.com> MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Although there're tons of arch-specific page fault handlers, most of them are still sharing the same initial value of the page fault flags. Say, merely all of the page fault handlers would allow the fault to be retried, and they also allow the fault to respond to SIGKILL. Let's define a default value for the fault flags to replace those initial page fault flags that were copied over. With this, it'll be far easier to introduce new fault flag that can be used by all the architectures instead of touching all the archs. Signed-off-by: Peter Xu Reviewed-by: David Hildenbrand --- arch/alpha/mm/fault.c | 2 +- arch/arc/mm/fault.c | 2 +- arch/arm/mm/fault.c | 2 +- arch/arm64/mm/fault.c | 2 +- arch/hexagon/mm/vm_fault.c | 2 +- arch/ia64/mm/fault.c | 2 +- arch/m68k/mm/fault.c | 2 +- arch/microblaze/mm/fault.c | 2 +- arch/mips/mm/fault.c | 2 +- arch/nds32/mm/fault.c | 2 +- arch/nios2/mm/fault.c | 2 +- arch/openrisc/mm/fault.c | 2 +- arch/parisc/mm/fault.c | 2 +- arch/powerpc/mm/fault.c | 2 +- arch/riscv/mm/fault.c | 2 +- arch/s390/mm/fault.c | 2 +- arch/sh/mm/fault.c | 2 +- arch/sparc/mm/fault_32.c | 2 +- arch/sparc/mm/fault_64.c | 2 +- arch/um/kernel/trap.c | 2 +- arch/unicore32/mm/fault.c | 2 +- arch/x86/mm/fault.c | 2 +- arch/xtensa/mm/fault.c | 2 +- include/linux/mm.h | 7 +++++++ 24 files changed, 30 insertions(+), 23 deletions(-) diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c index 741e61ef9d3f..de4cc6936391 100644 --- a/arch/alpha/mm/fault.c +++ b/arch/alpha/mm/fault.c @@ -89,7 +89,7 @@ do_page_fault(unsigned long address, unsigned long mmcsr, const struct exception_table_entry *fixup; int si_code = SEGV_MAPERR; vm_fault_t fault; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; /* As of EV6, a load into $31/$f31 is a prefetch, and never faults (or is suppressed by the PALcode). Support that for older CPUs diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c index 3861543b66a0..61919e4e4eec 100644 --- a/arch/arc/mm/fault.c +++ b/arch/arc/mm/fault.c @@ -94,7 +94,7 @@ void do_page_fault(unsigned long address, struct pt_regs *regs) (regs->ecr_cause == ECR_C_PROTV_INST_FETCH)) exec = 1; - flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + flags = FAULT_FLAG_DEFAULT; if (user_mode(regs)) flags |= FAULT_FLAG_USER; if (write) diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c index 890eeaac3cbb..2ae28ffec622 100644 --- a/arch/arm/mm/fault.c +++ b/arch/arm/mm/fault.c @@ -241,7 +241,7 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs) struct mm_struct *mm; int sig, code; vm_fault_t fault; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; if (kprobe_page_fault(regs, fsr)) return 0; diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index cfd65b63f36f..613e7434c208 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -410,7 +410,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, struct mm_struct *mm = current->mm; vm_fault_t fault, major = 0; unsigned long vm_flags = VM_READ | VM_WRITE; - unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int mm_flags = FAULT_FLAG_DEFAULT; if (kprobe_page_fault(regs, esr)) return 0; diff --git a/arch/hexagon/mm/vm_fault.c b/arch/hexagon/mm/vm_fault.c index b3bc71680ae4..223787e01bdd 100644 --- a/arch/hexagon/mm/vm_fault.c +++ b/arch/hexagon/mm/vm_fault.c @@ -41,7 +41,7 @@ void do_page_fault(unsigned long address, long cause, struct pt_regs *regs) int si_code = SEGV_MAPERR; vm_fault_t fault; const struct exception_table_entry *fixup; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; /* * If we're in an interrupt or have no user context, diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c index c2f299fe9e04..d039b846f671 100644 --- a/arch/ia64/mm/fault.c +++ b/arch/ia64/mm/fault.c @@ -65,7 +65,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re struct mm_struct *mm = current->mm; unsigned long mask; vm_fault_t fault; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; mask = ((((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT) | (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT)); diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c index e9b1d7585b43..8e734309ace9 100644 --- a/arch/m68k/mm/fault.c +++ b/arch/m68k/mm/fault.c @@ -71,7 +71,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, struct mm_struct *mm = current->mm; struct vm_area_struct * vma; vm_fault_t fault; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; pr_debug("do page fault:\nregs->sr=%#x, regs->pc=%#lx, address=%#lx, %ld, %p\n", regs->sr, regs->pc, address, error_code, mm ? mm->pgd : NULL); diff --git a/arch/microblaze/mm/fault.c b/arch/microblaze/mm/fault.c index e6a810b0c7ad..45c9f66c1dbc 100644 --- a/arch/microblaze/mm/fault.c +++ b/arch/microblaze/mm/fault.c @@ -91,7 +91,7 @@ void do_page_fault(struct pt_regs *regs, unsigned long address, int code = SEGV_MAPERR; int is_write = error_code & ESR_S; vm_fault_t fault; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; regs->ear = address; regs->esr = error_code; diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c index f589aa8f47d9..6660b77ff8f3 100644 --- a/arch/mips/mm/fault.c +++ b/arch/mips/mm/fault.c @@ -44,7 +44,7 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write, const int field = sizeof(unsigned long) * 2; int si_code; vm_fault_t fault; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10); diff --git a/arch/nds32/mm/fault.c b/arch/nds32/mm/fault.c index 064ae5d2159d..a40de112a23a 100644 --- a/arch/nds32/mm/fault.c +++ b/arch/nds32/mm/fault.c @@ -76,7 +76,7 @@ void do_page_fault(unsigned long entry, unsigned long addr, int si_code; vm_fault_t fault; unsigned int mask = VM_READ | VM_WRITE | VM_EXEC; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; error_code = error_code & (ITYPE_mskINST | ITYPE_mskETYPE); tsk = current; diff --git a/arch/nios2/mm/fault.c b/arch/nios2/mm/fault.c index 6a2e716b959f..a401b45cae47 100644 --- a/arch/nios2/mm/fault.c +++ b/arch/nios2/mm/fault.c @@ -47,7 +47,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long cause, struct mm_struct *mm = tsk->mm; int code = SEGV_MAPERR; vm_fault_t fault; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; cause >>= 2; diff --git a/arch/openrisc/mm/fault.c b/arch/openrisc/mm/fault.c index 5d4d3a9691d0..fd1592a56238 100644 --- a/arch/openrisc/mm/fault.c +++ b/arch/openrisc/mm/fault.c @@ -50,7 +50,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long address, struct vm_area_struct *vma; int si_code; vm_fault_t fault; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; tsk = current; diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c index adbd5e2144a3..355e3e13fa72 100644 --- a/arch/parisc/mm/fault.c +++ b/arch/parisc/mm/fault.c @@ -274,7 +274,7 @@ void do_page_fault(struct pt_regs *regs, unsigned long code, if (!mm) goto no_context; - flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + flags = FAULT_FLAG_DEFAULT; if (user_mode(regs)) flags |= FAULT_FLAG_USER; diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 8432c281de92..408ee769c470 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -435,7 +435,7 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address, { struct vm_area_struct * vma; struct mm_struct *mm = current->mm; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; int is_exec = TRAP(regs) == 0x400; int is_user = user_mode(regs); int is_write = page_fault_is_write(error_code); diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c index 96add1427a75..deeb820bd855 100644 --- a/arch/riscv/mm/fault.c +++ b/arch/riscv/mm/fault.c @@ -28,7 +28,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs) struct vm_area_struct *vma; struct mm_struct *mm; unsigned long addr, cause; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; int code = SEGV_MAPERR; vm_fault_t fault; diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 7b0bb475c166..74a77b2bca75 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -429,7 +429,7 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) address = trans_exc_code & __FAIL_ADDR_MASK; perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); - flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + flags = FAULT_FLAG_DEFAULT; if (user_mode(regs)) flags |= FAULT_FLAG_USER; if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400) diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c index 5f51456f4fc7..becf0be267bb 100644 --- a/arch/sh/mm/fault.c +++ b/arch/sh/mm/fault.c @@ -380,7 +380,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, struct mm_struct *mm; struct vm_area_struct * vma; vm_fault_t fault; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; tsk = current; mm = tsk->mm; diff --git a/arch/sparc/mm/fault_32.c b/arch/sparc/mm/fault_32.c index 8d69de111470..0863f6fdd2c5 100644 --- a/arch/sparc/mm/fault_32.c +++ b/arch/sparc/mm/fault_32.c @@ -168,7 +168,7 @@ asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write, int from_user = !(regs->psr & PSR_PS); int code; vm_fault_t fault; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; if (text_fault) address = regs->pc; diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c index 2371fb6b97e4..a1cba3eef79e 100644 --- a/arch/sparc/mm/fault_64.c +++ b/arch/sparc/mm/fault_64.c @@ -267,7 +267,7 @@ asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs) int si_code, fault_code; vm_fault_t fault; unsigned long address, mm_rss; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; fault_code = get_thread_fault_code(); diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c index 58fe36856182..bc2756782d64 100644 --- a/arch/um/kernel/trap.c +++ b/arch/um/kernel/trap.c @@ -32,7 +32,7 @@ int handle_page_fault(unsigned long address, unsigned long ip, pmd_t *pmd; pte_t *pte; int err = -EFAULT; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; *code_out = SEGV_MAPERR; diff --git a/arch/unicore32/mm/fault.c b/arch/unicore32/mm/fault.c index 76342de9cf8c..60453c892c51 100644 --- a/arch/unicore32/mm/fault.c +++ b/arch/unicore32/mm/fault.c @@ -202,7 +202,7 @@ static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs) struct mm_struct *mm; int sig, code; vm_fault_t fault; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; tsk = current; mm = tsk->mm; diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 9ceacd1156db..994c860ac2d8 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1287,7 +1287,7 @@ void do_user_addr_fault(struct pt_regs *regs, struct task_struct *tsk; struct mm_struct *mm; vm_fault_t fault, major = 0; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; tsk = current; mm = tsk->mm; diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c index f81b1478da61..d2b082908538 100644 --- a/arch/xtensa/mm/fault.c +++ b/arch/xtensa/mm/fault.c @@ -43,7 +43,7 @@ void do_page_fault(struct pt_regs *regs) int is_write, is_exec; vm_fault_t fault; - unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + unsigned int flags = FAULT_FLAG_DEFAULT; code = SEGV_MAPERR; diff --git a/include/linux/mm.h b/include/linux/mm.h index 0334ca97c584..57fb5c535f8e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -393,6 +393,13 @@ extern pgprot_t protection_map[16]; #define FAULT_FLAG_REMOTE 0x80 /* faulting for non current tsk/mm */ #define FAULT_FLAG_INSTRUCTION 0x100 /* The fault was during an instruction fetch */ +/* + * The default fault flags that should be used by most of the + * arch-specific page fault handlers. + */ +#define FAULT_FLAG_DEFAULT (FAULT_FLAG_ALLOW_RETRY | \ + FAULT_FLAG_KILLABLE) + #define FAULT_FLAG_TRACE \ { FAULT_FLAG_WRITE, "WRITE" }, \ { FAULT_FLAG_MKWRITE, "MKWRITE" }, \ From patchwork Thu Sep 5 10:15:30 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 11132631 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CD6E017EF for ; Thu, 5 Sep 2019 10:16:13 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 953F22184B for ; Thu, 5 Sep 2019 10:16:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 953F22184B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B1E536B027C; Thu, 5 Sep 2019 06:16:12 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id AF77F6B027D; Thu, 5 Sep 2019 06:16:12 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A0B196B027E; Thu, 5 Sep 2019 06:16:12 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0074.hostedemail.com [216.40.44.74]) by kanga.kvack.org (Postfix) with ESMTP id 7DE9D6B027C for ; Thu, 5 Sep 2019 06:16:12 -0400 (EDT) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id 0B49733C4 for ; Thu, 5 Sep 2019 10:16:12 +0000 (UTC) X-FDA: 75900461784.04.drain43_532c29924f82c X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,peterx@redhat.com,::linux-kernel@vger.kernel.org:david@redhat.com:hughd@google.com:gokhale2@llnl.gov:jglisse@redhat.com:xemul@virtuozzo.com:hannes@cmpxchg.org:peterx@redhat.com:cracauer@cons.org:mcfadden8@llnl.gov:shli@fb.com:aarcange@redhat.com:mike.kravetz@oracle.com:dplotnikov@virtuozzo.com:rppt@linux.vnet.ibm.com:torvalds@linux-foundation.org:mgorman@suse.de:kirill@shutemov.name:dgilbert@redhat.com,RULES_HIT:30051:30054:30070,0,RBL:209.132.183.28:@redhat.com:.lbl8.mailshell.net-62.18.0.0 64.10.201.10,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:ft,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:26,LUA_SUMMARY:none X-HE-Tag: drain43_532c29924f82c X-Filterd-Recvd-Size: 7669 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Thu, 5 Sep 2019 10:16:11 +0000 (UTC) Received: from mail-pf1-f200.google.com (mail-pf1-f200.google.com [209.85.210.200]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A32618830A for ; Thu, 5 Sep 2019 10:16:10 +0000 (UTC) Received: by mail-pf1-f200.google.com with SMTP id i28so1457979pfq.16 for ; Thu, 05 Sep 2019 03:16:10 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=RRZuHtIpu1kWmysN8fGt73f3ShagvK1FUD0BwRzbsQk=; b=j41dRbh9XwWL+3QqjWmd1c8Cw/FF0MDqx1ompgrCP6mmePeFKoNG+IV5iUwYXk/7ZH L1kM/tq/URrDEJffynv1MckNgUKgq9PR10tnFPc7sZ3WGPVAcG4EWQSEwaPQnbwGYXQb pHEmd2JsyGakQ1qrwCOA4zmjf8f7cE9gyCZlJMHigznwCWf6JOSgtEplMvtPELVYHF5H MuJ+xHXaNB3NnFe5sMJX5WC1FdfS7AZhxrw8Y2tydrceezewZTzi/0g/0UBsaAelyeVV 1XjUfaYYnh16TycuYZWg+OU9PWpaHTxu5fvJSaKC/xQNHC3punGqft6sx3nveOno3Ijs w7PA== X-Gm-Message-State: APjAAAWtRHXb0J+KPqCj5SLmU5Cf7KxDB/1UUsf3L8rIs0aqLemJkcGz ZQ73iE/jKzXuC+f5WF1hLDkUlCq01u2Aui9OstDZf3ObsJONrz3uo+i+25gXDcGyGdjNLGwnnWS vMelCsg5zdE8= X-Received: by 2002:aa7:81c1:: with SMTP id c1mr2745048pfn.78.1567678569689; Thu, 05 Sep 2019 03:16:09 -0700 (PDT) X-Google-Smtp-Source: APXvYqxQCYkfTar4nbC5tmBvHetw7MAXc9iDUbBdhXHz/m1fjU6zuFE95xDQuiuJUT/a/K9eLrCiTw== X-Received: by 2002:aa7:81c1:: with SMTP id c1mr2745012pfn.78.1567678569455; Thu, 05 Sep 2019 03:16:09 -0700 (PDT) Received: from xz-x1.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id a20sm413852pfo.33.2019.09.05.03.16.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Sep 2019 03:16:08 -0700 (PDT) From: Peter Xu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: David Hildenbrand , Hugh Dickins , Maya Gokhale , Jerome Glisse , Pavel Emelyanov , Johannes Weiner , peterx@redhat.com, Martin Cracauer , Marty McFadden , Shaohua Li , Andrea Arcangeli , Mike Kravetz , Denis Plotnikov , Mike Rapoport , Linus Torvalds , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" Subject: [PATCH v2 3/7] mm: Introduce FAULT_FLAG_INTERRUPTIBLE Date: Thu, 5 Sep 2019 18:15:30 +0800 Message-Id: <20190905101534.9637-4-peterx@redhat.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190905101534.9637-1-peterx@redhat.com> References: <20190905101534.9637-1-peterx@redhat.com> MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: handle_userfaultfd() is currently the only one place in the kernel page fault procedures that can respond to non-fatal userspace signals. It was trying to detect such an allowance by checking against USER & KILLABLE flags, which was "un-official". In this patch, we introduced a new flag (FAULT_FLAG_INTERRUPTIBLE) to show that the fault handler allows the fault procedure to respond even to non-fatal signals. Meanwhile, add this new flag to the default fault flags so that all the page fault handlers can benefit from the new flag. With that, replacing the userfault check to this one. Since the line is getting even longer, clean up the fault flags a bit too to ease TTY users. Although we've got a new flag and applied it, we shouldn't have any functional change with this patch so far. Suggested-by: Linus Torvalds Signed-off-by: Peter Xu --- fs/userfaultfd.c | 4 +--- include/linux/mm.h | 39 ++++++++++++++++++++++++++++----------- 2 files changed, 29 insertions(+), 14 deletions(-) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index ccbdbd62f0d8..4a8ad2dc2b6f 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -462,9 +462,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason) uwq.ctx = ctx; uwq.waken = false; - return_to_userland = - (vmf->flags & (FAULT_FLAG_USER|FAULT_FLAG_KILLABLE)) == - (FAULT_FLAG_USER|FAULT_FLAG_KILLABLE); + return_to_userland = vmf->flags & FAULT_FLAG_INTERRUPTIBLE; blocking_state = return_to_userland ? TASK_INTERRUPTIBLE : TASK_KILLABLE; diff --git a/include/linux/mm.h b/include/linux/mm.h index 57fb5c535f8e..53ec7abb8472 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -383,22 +383,38 @@ extern unsigned int kobjsize(const void *objp); */ extern pgprot_t protection_map[16]; -#define FAULT_FLAG_WRITE 0x01 /* Fault was a write access */ -#define FAULT_FLAG_MKWRITE 0x02 /* Fault was mkwrite of existing pte */ -#define FAULT_FLAG_ALLOW_RETRY 0x04 /* Retry fault if blocking */ -#define FAULT_FLAG_RETRY_NOWAIT 0x08 /* Don't drop mmap_sem and wait when retrying */ -#define FAULT_FLAG_KILLABLE 0x10 /* The fault task is in SIGKILL killable region */ -#define FAULT_FLAG_TRIED 0x20 /* Second try */ -#define FAULT_FLAG_USER 0x40 /* The fault originated in userspace */ -#define FAULT_FLAG_REMOTE 0x80 /* faulting for non current tsk/mm */ -#define FAULT_FLAG_INSTRUCTION 0x100 /* The fault was during an instruction fetch */ +/** + * Fault flag definitions. + * + * @FAULT_FLAG_WRITE: Fault was a write fault. + * @FAULT_FLAG_MKWRITE: Fault was mkwrite of existing PTE. + * @FAULT_FLAG_ALLOW_RETRY: Allow to retry the fault if blocked. + * @FAULT_FLAG_RETRY_NOWAIT: Don't drop mmap_sem and wait when retrying. + * @FAULT_FLAG_KILLABLE: The fault task is in SIGKILL killable region. + * @FAULT_FLAG_TRIED: The fault has been tried once. + * @FAULT_FLAG_USER: The fault originated in userspace. + * @FAULT_FLAG_REMOTE: The fault is not for current task/mm. + * @FAULT_FLAG_INSTRUCTION: The fault was during an instruction fetch. + * @FAULT_FLAG_INTERRUPTIBLE: The fault can be interrupted by non-fatal signals. + */ +#define FAULT_FLAG_WRITE 0x01 +#define FAULT_FLAG_MKWRITE 0x02 +#define FAULT_FLAG_ALLOW_RETRY 0x04 +#define FAULT_FLAG_RETRY_NOWAIT 0x08 +#define FAULT_FLAG_KILLABLE 0x10 +#define FAULT_FLAG_TRIED 0x20 +#define FAULT_FLAG_USER 0x40 +#define FAULT_FLAG_REMOTE 0x80 +#define FAULT_FLAG_INSTRUCTION 0x100 +#define FAULT_FLAG_INTERRUPTIBLE 0x200 /* * The default fault flags that should be used by most of the * arch-specific page fault handlers. */ #define FAULT_FLAG_DEFAULT (FAULT_FLAG_ALLOW_RETRY | \ - FAULT_FLAG_KILLABLE) + FAULT_FLAG_KILLABLE | \ + FAULT_FLAG_INTERRUPTIBLE) #define FAULT_FLAG_TRACE \ { FAULT_FLAG_WRITE, "WRITE" }, \ @@ -409,7 +425,8 @@ extern pgprot_t protection_map[16]; { FAULT_FLAG_TRIED, "TRIED" }, \ { FAULT_FLAG_USER, "USER" }, \ { FAULT_FLAG_REMOTE, "REMOTE" }, \ - { FAULT_FLAG_INSTRUCTION, "INSTRUCTION" } + { FAULT_FLAG_INSTRUCTION, "INSTRUCTION" }, \ + { FAULT_FLAG_INTERRUPTIBLE, "INTERRUPTIBLE" } /* * vm_fault is filled by the the pagefault handler and passed to the vma's From patchwork Thu Sep 5 10:15:31 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 11132633 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5CD521805 for ; Thu, 5 Sep 2019 10:16:22 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1815A2184B for ; Thu, 5 Sep 2019 10:16:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1815A2184B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2B9B26B027D; Thu, 5 Sep 2019 06:16:21 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 26AB56B027E; Thu, 5 Sep 2019 06:16:21 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 10B466B027F; Thu, 5 Sep 2019 06:16:21 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0136.hostedemail.com [216.40.44.136]) by kanga.kvack.org (Postfix) with ESMTP id DE5E66B027D for ; Thu, 5 Sep 2019 06:16:20 -0400 (EDT) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 828F518C9 for ; Thu, 5 Sep 2019 10:16:20 +0000 (UTC) X-FDA: 75900462120.16.gold90_546318049e942 X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,peterx@redhat.com,::linux-kernel@vger.kernel.org:david@redhat.com:hughd@google.com:gokhale2@llnl.gov:jglisse@redhat.com:xemul@virtuozzo.com:hannes@cmpxchg.org:peterx@redhat.com:cracauer@cons.org:mcfadden8@llnl.gov:shli@fb.com:aarcange@redhat.com:mike.kravetz@oracle.com:dplotnikov@virtuozzo.com:rppt@linux.vnet.ibm.com:torvalds@linux-foundation.org:mgorman@suse.de:kirill@shutemov.name:dgilbert@redhat.com,RULES_HIT:30003:30012:30045:30051:30054:30070,0,RBL:209.132.183.28:@redhat.com:.lbl8.mailshell.net-62.18.0.0 64.10.201.10,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:ft,MSBL:0,DNSBL:neutral,Custom_rules:0:1:0,LFtime:25,LUA_SUMMARY:none X-HE-Tag: gold90_546318049e942 X-Filterd-Recvd-Size: 19799 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by imf27.hostedemail.com (Postfix) with ESMTP for ; Thu, 5 Sep 2019 10:16:19 +0000 (UTC) Received: from mail-pl1-f197.google.com (mail-pl1-f197.google.com [209.85.214.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E82F983F4C for ; Thu, 5 Sep 2019 10:16:18 +0000 (UTC) Received: by mail-pl1-f197.google.com with SMTP id p8so1164784plo.16 for ; Thu, 05 Sep 2019 03:16:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=0nEw8OAi2qZaszwJFzF1LByyK8VJPwpm+mPV/8Jjhrc=; b=LI0ZZBMbh2tOGr7vvOI7iN//Hh8Jo1gP8el+STAFEWZnpWFZqkg1Ci//d6wHJeDOyF ORPS6+9cwnHysFfoNMeq+ykOpssRopo0RGRzrkyzv//gblzzMq7jUyK1VoMEJQeyvpDO mCFdcMMBvm1sQf6Q9p6whHJsS4pR1LEIsp2vx6qxSnNJBYDdbaqDDzgSUCuX91v560f7 GIB29kbMG0dczvMuA6VMdjlgCXoEWRU2f/rngKoIRYfQx90Cc5GzRYVLLM64ci0ehWZo 2I02g7q4AhgsAVDGZuIftyRvHNpeo7vscfrRf2yS/mLOTX8GE1egegJzv1xDj1Tt9CNE E6hQ== X-Gm-Message-State: APjAAAWVqSJsh5gCQiQNn1agMQ92gs1lmcWLcvLMir1kCb2rkWTWbnZo QPpmdZ1TewnW9atJFJ6FxkhIH0ICePcSSsABKrVRiENf2hbbSd8WeFDX7079BQMw36+lkak92aO T1ULxNjKCt/k= X-Received: by 2002:a62:5c82:: with SMTP id q124mr2808631pfb.177.1567678576893; Thu, 05 Sep 2019 03:16:16 -0700 (PDT) X-Google-Smtp-Source: APXvYqysT1m7vk6lgTK6kdLEQ+LxGM8orMM70ijZ61Jcp494v9V6bXsGHBlIrCGnf+vZm6rgPUQPZA== X-Received: by 2002:a62:5c82:: with SMTP id q124mr2808577pfb.177.1567678576538; Thu, 05 Sep 2019 03:16:16 -0700 (PDT) Received: from xz-x1.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id a20sm413852pfo.33.2019.09.05.03.16.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Sep 2019 03:16:15 -0700 (PDT) From: Peter Xu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: David Hildenbrand , Hugh Dickins , Maya Gokhale , Jerome Glisse , Pavel Emelyanov , Johannes Weiner , peterx@redhat.com, Martin Cracauer , Marty McFadden , Shaohua Li , Andrea Arcangeli , Mike Kravetz , Denis Plotnikov , Mike Rapoport , Linus Torvalds , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" Subject: [PATCH v2 4/7] mm: Return faster for non-fatal signals in user mode faults Date: Thu, 5 Sep 2019 18:15:31 +0800 Message-Id: <20190905101534.9637-5-peterx@redhat.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190905101534.9637-1-peterx@redhat.com> References: <20190905101534.9637-1-peterx@redhat.com> MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: The idea comes from the upstream discussion between Linus and Andrea: https://lkml.org/lkml/2017/10/30/560 A summary to the issue: there was a special path in handle_userfault() in the past that we'll return a VM_FAULT_NOPAGE when we detected non-fatal signals when waiting for userfault handling. We did that by reacquiring the mmap_sem before returning. However that brings a risk in that the vmas might have changed when we retake the mmap_sem and even we could be holding an invalid vma structure. This patch is a preparation of removing that special path by allowing the page fault to return even faster if we were interrupted by a non-fatal signal during a user-mode page fault handling routine. Suggested-by: Linus Torvalds Suggested-by: Andrea Arcangeli Signed-off-by: Peter Xu --- arch/alpha/mm/fault.c | 3 ++- arch/arc/mm/fault.c | 5 +++++ arch/arm/mm/fault.c | 9 +++++---- arch/arm64/mm/fault.c | 9 +++++---- arch/hexagon/mm/vm_fault.c | 3 ++- arch/ia64/mm/fault.c | 3 ++- arch/m68k/mm/fault.c | 5 +++-- arch/microblaze/mm/fault.c | 3 ++- arch/mips/mm/fault.c | 3 ++- arch/nds32/mm/fault.c | 9 +++++---- arch/nios2/mm/fault.c | 3 ++- arch/openrisc/mm/fault.c | 3 ++- arch/parisc/mm/fault.c | 3 ++- arch/powerpc/mm/fault.c | 2 ++ arch/riscv/mm/fault.c | 5 +++-- arch/s390/mm/fault.c | 4 ++-- arch/sh/mm/fault.c | 4 ++++ arch/sparc/mm/fault_32.c | 2 +- arch/sparc/mm/fault_64.c | 3 ++- arch/um/kernel/trap.c | 4 +++- arch/unicore32/mm/fault.c | 5 +++-- arch/x86/mm/fault.c | 2 ++ arch/xtensa/mm/fault.c | 3 ++- include/linux/sched/signal.h | 12 ++++++++++++ 24 files changed, 75 insertions(+), 32 deletions(-) diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c index de4cc6936391..ab1d4212d658 100644 --- a/arch/alpha/mm/fault.c +++ b/arch/alpha/mm/fault.c @@ -150,7 +150,8 @@ do_page_fault(unsigned long address, unsigned long mmcsr, the fault. */ fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c index 61919e4e4eec..27adf4e608e4 100644 --- a/arch/arc/mm/fault.c +++ b/arch/arc/mm/fault.c @@ -142,6 +142,11 @@ void do_page_fault(unsigned long address, struct pt_regs *regs) goto no_context; return; } + + /* Allow user to handle non-fatal signals first */ + if (signal_pending(current) && user_mode(regs)) + return; + /* * retry state machine */ diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c index 2ae28ffec622..f00fb4eafe54 100644 --- a/arch/arm/mm/fault.c +++ b/arch/arm/mm/fault.c @@ -291,14 +291,15 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs) fault = __do_page_fault(mm, addr, fsr, flags, tsk); - /* If we need to retry but a fatal signal is pending, handle the + /* If we need to retry but a signal is pending, try to handle the * signal first. We do not need to release the mmap_sem because * it would already be released in __lock_page_or_retry in * mm/filemap.c. */ - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { - if (!user_mode(regs)) + if (unlikely(fault & VM_FAULT_RETRY && signal_pending(current))) { + if (fatal_signal_pending(current) && !user_mode(regs)) goto no_context; - return 0; + if (user_mode(regs)) + return 0; } /* diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 613e7434c208..0d3fe0ea6a70 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -479,15 +479,16 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, if (fault & VM_FAULT_RETRY) { /* - * If we need to retry but a fatal signal is pending, + * If we need to retry but a signal is pending, try to * handle the signal first. We do not need to release * the mmap_sem because it would already be released * in __lock_page_or_retry in mm/filemap.c. */ - if (fatal_signal_pending(current)) { - if (!user_mode(regs)) + if (signal_pending(current)) { + if (fatal_signal_pending(current) && !user_mode(regs)) goto no_context; - return 0; + if (user_mode(regs)) + return 0; } /* diff --git a/arch/hexagon/mm/vm_fault.c b/arch/hexagon/mm/vm_fault.c index 223787e01bdd..88a2e5635bfb 100644 --- a/arch/hexagon/mm/vm_fault.c +++ b/arch/hexagon/mm/vm_fault.c @@ -91,7 +91,8 @@ void do_page_fault(unsigned long address, long cause, struct pt_regs *regs) fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; /* The most common case -- we are done. */ diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c index d039b846f671..8d47acf50fda 100644 --- a/arch/ia64/mm/fault.c +++ b/arch/ia64/mm/fault.c @@ -141,7 +141,8 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re */ fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c index 8e734309ace9..103f93ba8139 100644 --- a/arch/m68k/mm/fault.c +++ b/arch/m68k/mm/fault.c @@ -138,8 +138,9 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, fault = handle_mm_fault(vma, address, flags); pr_debug("handle_mm_fault returns %x\n", fault); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) - return 0; + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) + return; if (unlikely(fault & VM_FAULT_ERROR)) { if (fault & VM_FAULT_OOM) diff --git a/arch/microblaze/mm/fault.c b/arch/microblaze/mm/fault.c index 45c9f66c1dbc..8b0615eab4b6 100644 --- a/arch/microblaze/mm/fault.c +++ b/arch/microblaze/mm/fault.c @@ -217,7 +217,8 @@ void do_page_fault(struct pt_regs *regs, unsigned long address, */ fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c index 6660b77ff8f3..48aac20a1ded 100644 --- a/arch/mips/mm/fault.c +++ b/arch/mips/mm/fault.c @@ -154,7 +154,8 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write, */ fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); diff --git a/arch/nds32/mm/fault.c b/arch/nds32/mm/fault.c index a40de112a23a..baa44f9d0b4a 100644 --- a/arch/nds32/mm/fault.c +++ b/arch/nds32/mm/fault.c @@ -206,14 +206,15 @@ void do_page_fault(unsigned long entry, unsigned long addr, fault = handle_mm_fault(vma, addr, flags); /* - * If we need to retry but a fatal signal is pending, handle the + * If we need to retry but a signal is pending, try to handle the * signal first. We do not need to release the mmap_sem because it * would already be released in __lock_page_or_retry in mm/filemap.c. */ - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { - if (!user_mode(regs)) + if ((fault & VM_FAULT_RETRY) && signal_pending(current)) { + if (fatal_signal_pending(current) && !user_mode(regs)) goto no_context; - return; + if (user_mode(regs)) + return; } if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/nios2/mm/fault.c b/arch/nios2/mm/fault.c index a401b45cae47..f9f178484184 100644 --- a/arch/nios2/mm/fault.c +++ b/arch/nios2/mm/fault.c @@ -133,7 +133,8 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long cause, */ fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/openrisc/mm/fault.c b/arch/openrisc/mm/fault.c index fd1592a56238..8ba3696dd10c 100644 --- a/arch/openrisc/mm/fault.c +++ b/arch/openrisc/mm/fault.c @@ -161,7 +161,8 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long address, fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c index 355e3e13fa72..163dcb080c7b 100644 --- a/arch/parisc/mm/fault.c +++ b/arch/parisc/mm/fault.c @@ -304,7 +304,8 @@ void do_page_fault(struct pt_regs *regs, unsigned long code, fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 408ee769c470..d321a6c5fe62 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -596,6 +596,8 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address, */ flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; + if (is_user && signal_pending(current)) + return 0; if (!fatal_signal_pending(current)) goto retry; } diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c index deeb820bd855..ea8f301de65b 100644 --- a/arch/riscv/mm/fault.c +++ b/arch/riscv/mm/fault.c @@ -111,11 +111,12 @@ asmlinkage void do_page_fault(struct pt_regs *regs) fault = handle_mm_fault(vma, addr, flags); /* - * If we need to retry but a fatal signal is pending, handle the + * If we need to retry but a signal is pending, try to handle the * signal first. We do not need to release the mmap_sem because it * would already be released in __lock_page_or_retry in mm/filemap.c. */ - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(tsk)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 74a77b2bca75..3ad77501deef 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -480,8 +480,8 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) * the fault. */ fault = handle_mm_fault(vma, address, flags); - /* No reason to continue if interrupted by SIGKILL. */ - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) { fault = VM_FAULT_SIGNAL; if (flags & FAULT_FLAG_RETRY_NOWAIT) goto out_up; diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c index becf0be267bb..f620282a37fd 100644 --- a/arch/sh/mm/fault.c +++ b/arch/sh/mm/fault.c @@ -489,6 +489,10 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, * have already released it in __lock_page_or_retry * in mm/filemap.c. */ + + if (user_mode(regs) && signal_pending(tsk)) + return; + goto retry; } } diff --git a/arch/sparc/mm/fault_32.c b/arch/sparc/mm/fault_32.c index 0863f6fdd2c5..9af0c3ad50d6 100644 --- a/arch/sparc/mm/fault_32.c +++ b/arch/sparc/mm/fault_32.c @@ -237,7 +237,7 @@ asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write, */ fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && fault_should_check_signal(from_user)) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c index a1cba3eef79e..566f05f9040b 100644 --- a/arch/sparc/mm/fault_64.c +++ b/arch/sparc/mm/fault_64.c @@ -421,7 +421,8 @@ asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs) fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(flags & FAULT_FLAG_USER)) goto exit_exception; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c index bc2756782d64..3c72111f27e9 100644 --- a/arch/um/kernel/trap.c +++ b/arch/um/kernel/trap.c @@ -76,7 +76,9 @@ int handle_page_fault(unsigned long address, unsigned long ip, fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(is_user)) goto out_nosemaphore; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/unicore32/mm/fault.c b/arch/unicore32/mm/fault.c index 60453c892c51..04c193439c97 100644 --- a/arch/unicore32/mm/fault.c +++ b/arch/unicore32/mm/fault.c @@ -246,11 +246,12 @@ static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs) fault = __do_pf(mm, addr, fsr, flags, tsk); - /* If we need to retry but a fatal signal is pending, handle the + /* If we need to retry but a signal is pending, try to handle the * signal first. We do not need to release the mmap_sem because * it would already be released in __lock_page_or_retry in * mm/filemap.c. */ - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return 0; if (!(fault & VM_FAULT_ERROR) && (flags & FAULT_FLAG_ALLOW_RETRY)) { diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 994c860ac2d8..f7836472961e 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1451,6 +1451,8 @@ void do_user_addr_fault(struct pt_regs *regs, if (flags & FAULT_FLAG_ALLOW_RETRY) { flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; + if ((flags & FAULT_FLAG_USER) && signal_pending(tsk)) + return; if (!fatal_signal_pending(tsk)) goto retry; } diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c index d2b082908538..094606676c36 100644 --- a/arch/xtensa/mm/fault.c +++ b/arch/xtensa/mm/fault.c @@ -110,7 +110,8 @@ void do_page_fault(struct pt_regs *regs) */ fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if ((fault & VM_FAULT_RETRY) && + fault_should_check_signal(user_mode(regs))) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h index efd8ce7675ed..ccce63f2822d 100644 --- a/include/linux/sched/signal.h +++ b/include/linux/sched/signal.h @@ -377,6 +377,18 @@ static inline int signal_pending_state(long state, struct task_struct *p) return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p); } +/* + * This should only be used in fault handlers to decide whether we + * should stop the current fault routine to handle the signals + * instead. It should normally be used when a signal interrupted a + * page fault which can lead to a VM_FAULT_RETRY. + */ +static inline bool fault_should_check_signal(bool is_user) +{ + return (fatal_signal_pending(current) || + (is_user && signal_pending(current))); +} + /* * Reevaluate whether the task has signals pending delivery. * Wake the task if so. From patchwork Thu Sep 5 10:15:32 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 11132635 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 970DC1805 for ; Thu, 5 Sep 2019 10:16:28 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6D1732184B for ; Thu, 5 Sep 2019 10:16:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6D1732184B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 837D26B027E; Thu, 5 Sep 2019 06:16:27 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 7E8B46B027F; Thu, 5 Sep 2019 06:16:27 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6B1076B0280; Thu, 5 Sep 2019 06:16:27 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0108.hostedemail.com [216.40.44.108]) by kanga.kvack.org (Postfix) with ESMTP id 4C36C6B027E for ; Thu, 5 Sep 2019 06:16:27 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id E0A3F181AC9AE for ; Thu, 5 Sep 2019 10:16:26 +0000 (UTC) X-FDA: 75900462372.21.range91_555322c15283b X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,peterx@redhat.com,::linux-kernel@vger.kernel.org:david@redhat.com:hughd@google.com:gokhale2@llnl.gov:jglisse@redhat.com:xemul@virtuozzo.com:hannes@cmpxchg.org:peterx@redhat.com:cracauer@cons.org:mcfadden8@llnl.gov:shli@fb.com:aarcange@redhat.com:mike.kravetz@oracle.com:dplotnikov@virtuozzo.com:rppt@linux.vnet.ibm.com:torvalds@linux-foundation.org:mgorman@suse.de:kirill@shutemov.name:dgilbert@redhat.com,RULES_HIT:30012:30054:30091,0,RBL:209.132.183.28:@redhat.com:.lbl8.mailshell.net-62.18.0.0 64.10.201.10,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:ft,MSBL:0,DNSBL:neutral,Custom_rules:0:1:0,LFtime:2,LUA_SUMMARY:none X-HE-Tag: range91_555322c15283b X-Filterd-Recvd-Size: 5676 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by imf41.hostedemail.com (Postfix) with ESMTP for ; Thu, 5 Sep 2019 10:16:26 +0000 (UTC) Received: from mail-pf1-f198.google.com (mail-pf1-f198.google.com [209.85.210.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 62D6183F51 for ; Thu, 5 Sep 2019 10:16:25 +0000 (UTC) Received: by mail-pf1-f198.google.com with SMTP id z23so1493762pfn.0 for ; Thu, 05 Sep 2019 03:16:25 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=SCWgxmciM/l530v7wrFJtbFp6IYoQ8sTPq58RJeE1HI=; b=Q4NeZsSa037Lg7Yt3JPR/lre3X1+djUN/NhH5FoPGazSSxlLUaEFrFXp6FBr5BnPkt q/s3q5IpStj8qLHY2CRUOyx7ZhJZooyysc4PBOGk2e8icNY0gp/hKx6weQeOUJ46nuFi VGsBVGq29wBNl7q+7VF/4ZroHGc/pviCXHm9Vdo/QEfax58Wi2QJOOdho+4ZdxNi1RF2 SF5q1a3XYgPzMscsbY6fqVc3PPpOcvSqMygocvgYBuDsX7wiB2e0SdnKK6e9Ays4Dd9B b9GPTvIO8tKpvfcnYG0VeYo5eOtUS87Dp4CY1+7H7GN5v9hLvkXMImyDi17dRYSoHFPj NZRw== X-Gm-Message-State: APjAAAVz9dXk40qSaLtEZeZg9lRNh/o6/1Qj3q3yZ79oqb599g+J8/nl qpYvzlFdmPYj0dZ/EgCqJNTs7ARgF17Qga2lHnBX+iN45ycj803nZahTZz8CQbAFlmRykUH7yvS iwUERWMMbZaI= X-Received: by 2002:a17:902:988a:: with SMTP id s10mr2410544plp.119.1567678584563; Thu, 05 Sep 2019 03:16:24 -0700 (PDT) X-Google-Smtp-Source: APXvYqySfDc/zhOFXj3cLsVFTtpVlLwUaGTCQLDhWRP0rJ8KpSGAK+5oupbPfAYaTJR2LP4bgKauaA== X-Received: by 2002:a17:902:988a:: with SMTP id s10mr2410525plp.119.1567678584389; Thu, 05 Sep 2019 03:16:24 -0700 (PDT) Received: from xz-x1.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id a20sm413852pfo.33.2019.09.05.03.16.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Sep 2019 03:16:23 -0700 (PDT) From: Peter Xu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: David Hildenbrand , Hugh Dickins , Maya Gokhale , Jerome Glisse , Pavel Emelyanov , Johannes Weiner , peterx@redhat.com, Martin Cracauer , Marty McFadden , Shaohua Li , Andrea Arcangeli , Mike Kravetz , Denis Plotnikov , Mike Rapoport , Linus Torvalds , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" Subject: [PATCH v2 5/7] userfaultfd: Don't retake mmap_sem to emulate NOPAGE Date: Thu, 5 Sep 2019 18:15:32 +0800 Message-Id: <20190905101534.9637-6-peterx@redhat.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190905101534.9637-1-peterx@redhat.com> References: <20190905101534.9637-1-peterx@redhat.com> MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: The idea comes from the upstream discussion between Linus and Andrea: https://lkml.org/lkml/2017/10/30/560 A summary to the issue: there was a special path in handle_userfault() in the past that we'll return a VM_FAULT_NOPAGE when we detected non-fatal signals when waiting for userfault handling. We did that by reacquiring the mmap_sem before returning. However that brings a risk in that the vmas might have changed when we retake the mmap_sem and even we could be holding an invalid vma structure. This patch removes the risk path in handle_userfault() then we will be sure that the callers of handle_mm_fault() will know that the VMAs might have changed. Meanwhile with previous patch we don't lose responsiveness as well since the core mm code now can handle the nonfatal userspace signals quickly even if we return VM_FAULT_RETRY. Suggested-by: Andrea Arcangeli Suggested-by: Linus Torvalds Reviewed-by: Jerome Glisse Signed-off-by: Peter Xu --- fs/userfaultfd.c | 24 ------------------------ 1 file changed, 24 deletions(-) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 4a8ad2dc2b6f..48b7ecf39f25 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -522,30 +522,6 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason) __set_current_state(TASK_RUNNING); - if (return_to_userland) { - if (signal_pending(current) && - !fatal_signal_pending(current)) { - /* - * If we got a SIGSTOP or SIGCONT and this is - * a normal userland page fault, just let - * userland return so the signal will be - * handled and gdb debugging works. The page - * fault code immediately after we return from - * this function is going to release the - * mmap_sem and it's not depending on it - * (unlike gup would if we were not to return - * VM_FAULT_RETRY). - * - * If a fatal signal is pending we still take - * the streamlined VM_FAULT_RETRY failure path - * and there's no need to retake the mmap_sem - * in such case. - */ - down_read(&mm->mmap_sem); - ret = VM_FAULT_NOPAGE; - } - } - /* * Here we race with the list_del; list_add in * userfaultfd_ctx_read(), however because we don't ever run From patchwork Thu Sep 5 10:15:33 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 11132637 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 48BB21813 for ; Thu, 5 Sep 2019 10:16:40 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 040DF21743 for ; Thu, 5 Sep 2019 10:16:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 040DF21743 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 180C26B0280; Thu, 5 Sep 2019 06:16:39 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 131C36B0281; Thu, 5 Sep 2019 06:16:39 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F13FA6B0282; Thu, 5 Sep 2019 06:16:38 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0190.hostedemail.com [216.40.44.190]) by kanga.kvack.org (Postfix) with ESMTP id C917D6B0280 for ; Thu, 5 Sep 2019 06:16:38 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id 5F71833C4 for ; Thu, 5 Sep 2019 10:16:38 +0000 (UTC) X-FDA: 75900462876.23.rest73_56fb9e3c20b2b X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,peterx@redhat.com,::linux-kernel@vger.kernel.org:david@redhat.com:hughd@google.com:gokhale2@llnl.gov:jglisse@redhat.com:xemul@virtuozzo.com:hannes@cmpxchg.org:peterx@redhat.com:cracauer@cons.org:mcfadden8@llnl.gov:shli@fb.com:aarcange@redhat.com:mike.kravetz@oracle.com:dplotnikov@virtuozzo.com:rppt@linux.vnet.ibm.com:torvalds@linux-foundation.org:mgorman@suse.de:kirill@shutemov.name:dgilbert@redhat.com,RULES_HIT:30003:30012:30045:30054:30070:30075,0,RBL:209.132.183.28:@redhat.com:.lbl8.mailshell.net-62.18.0.0 64.10.201.10,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:ft,MSBL:0,DNSBL:neutral,Custom_rules:0:1:0,LFtime:24,LUA_SUMMARY:none X-HE-Tag: rest73_56fb9e3c20b2b X-Filterd-Recvd-Size: 23353 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by imf32.hostedemail.com (Postfix) with ESMTP for ; Thu, 5 Sep 2019 10:16:37 +0000 (UTC) Received: from mail-pg1-f198.google.com (mail-pg1-f198.google.com [209.85.215.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E116E7FDCD for ; Thu, 5 Sep 2019 10:16:36 +0000 (UTC) Received: by mail-pg1-f198.google.com with SMTP id j9so1046850pgk.20 for ; Thu, 05 Sep 2019 03:16:36 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=RteZilvrp+Hc7vY9UjUpix1iBfAzoNk2FpSYPfWtuOg=; b=fSe+d3dX1eHoGbg2mrWVj3uuJOTMAQjzNskS5uI8y6dHOsRY1XmSKHAabJ2+mGeQvD 7n9o7GKYoRom0zesxvTBnkpYzdPkOgm73HhmMfA402QogRiadiOVRMkJEXxk+e3gttUk zrg9pMspaWdOA7UUjYctPs+3ARpIPSw8Z/U40BDsHEZQKESy41iESu9mm7veR7+i5DdC s4kmBwtQ4B8Fheed5BG/VWOVQPd+49Z8XhOYWfqPGl97cXsDvaC9CNAZkYhEhT9g0H+V DlwiS5z9hI5CZKO+dAhRtCaZbUv677Jt/K32gBJHBaR335NCj4Jvc1fu0vCc0l1yBhsI Y7NQ== X-Gm-Message-State: APjAAAXaKNlj4EFhldi8PzLHi4PvvVqZg/PUaBdUOwEtXWRWGWynORBY jC2AviEYQlHs+zlZrSScbEkMgCwfzhJKgYSavrH3Ktg0hzwkt/CkGU4KuSRoyKdoSVOL/HnZoyM wl/WrV1kgAc4= X-Received: by 2002:a63:3281:: with SMTP id y123mr2391215pgy.72.1567678593132; Thu, 05 Sep 2019 03:16:33 -0700 (PDT) X-Google-Smtp-Source: APXvYqw1OGsp/NktJaenQgr+yyFTh2aKfT8BiJepklJ1WI0g7CnD2Y9Ej4xCn/aAmBRWG1PYrhzIjg== X-Received: by 2002:a63:3281:: with SMTP id y123mr2391154pgy.72.1567678592422; Thu, 05 Sep 2019 03:16:32 -0700 (PDT) Received: from xz-x1.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id a20sm413852pfo.33.2019.09.05.03.16.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Sep 2019 03:16:31 -0700 (PDT) From: Peter Xu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: David Hildenbrand , Hugh Dickins , Maya Gokhale , Jerome Glisse , Pavel Emelyanov , Johannes Weiner , peterx@redhat.com, Martin Cracauer , Marty McFadden , Shaohua Li , Andrea Arcangeli , Mike Kravetz , Denis Plotnikov , Mike Rapoport , Linus Torvalds , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" Subject: [PATCH v2 6/7] mm: Allow VM_FAULT_RETRY for multiple times Date: Thu, 5 Sep 2019 18:15:33 +0800 Message-Id: <20190905101534.9637-7-peterx@redhat.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190905101534.9637-1-peterx@redhat.com> References: <20190905101534.9637-1-peterx@redhat.com> MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: The idea comes from a discussion between Linus and Andrea [1]. Before this patch we only allow a page fault to retry once. We achieved this by clearing the FAULT_FLAG_ALLOW_RETRY flag when doing handle_mm_fault() the second time. This was majorly used to avoid unexpected starvation of the system by looping over forever to handle the page fault on a single page. However that should hardly happen, and after all for each code path to return a VM_FAULT_RETRY we'll first wait for a condition (during which time we should possibly yield the cpu) to happen before VM_FAULT_RETRY is really returned. This patch removes the restriction by keeping the FAULT_FLAG_ALLOW_RETRY flag when we receive VM_FAULT_RETRY. It means that the page fault handler now can retry the page fault for multiple times if necessary without the need to generate another page fault event. Meanwhile we still keep the FAULT_FLAG_TRIED flag so page fault handler can still identify whether a page fault is the first attempt or not. Then we'll have these combinations of fault flags (only considering ALLOW_RETRY flag and TRIED flag): - ALLOW_RETRY and !TRIED: this means the page fault allows to retry, and this is the first try - ALLOW_RETRY and TRIED: this means the page fault allows to retry, and this is not the first try - !ALLOW_RETRY and !TRIED: this means the page fault does not allow to retry at all - !ALLOW_RETRY and TRIED: this is forbidden and should never be used In existing code we have multiple places that has taken special care of the first condition above by checking against (fault_flags & FAULT_FLAG_ALLOW_RETRY). This patch introduces a simple helper to detect the first retry of a page fault by checking against both (fault_flags & FAULT_FLAG_ALLOW_RETRY) and !(fault_flag & FAULT_FLAG_TRIED) because now even the 2nd try will have the ALLOW_RETRY set, then use that helper in all existing special paths. One example is in __lock_page_or_retry(), now we'll drop the mmap_sem only in the first attempt of page fault and we'll keep it in follow up retries, so old locking behavior will be retained. This will be a nice enhancement for current code [2] at the same time a supporting material for the future userfaultfd-writeprotect work, since in that work there will always be an explicit userfault writeprotect retry for protected pages, and if that cannot resolve the page fault (e.g., when userfaultfd-writeprotect is used in conjunction with swapped pages) then we'll possibly need a 3rd retry of the page fault. It might also benefit other potential users who will have similar requirement like userfault write-protection. GUP code is not touched yet and will be covered in follow up patch. Please read the thread below for more information. [1] https://lkml.org/lkml/2017/11/2/833 [2] https://lkml.org/lkml/2018/12/30/64 Suggested-by: Linus Torvalds Suggested-by: Andrea Arcangeli Reviewed-by: Jerome Glisse Signed-off-by: Peter Xu --- arch/alpha/mm/fault.c | 2 +- arch/arc/mm/fault.c | 1 - arch/arm/mm/fault.c | 3 --- arch/arm64/mm/fault.c | 5 ----- arch/hexagon/mm/vm_fault.c | 1 - arch/ia64/mm/fault.c | 1 - arch/m68k/mm/fault.c | 3 --- arch/microblaze/mm/fault.c | 1 - arch/mips/mm/fault.c | 1 - arch/nds32/mm/fault.c | 1 - arch/nios2/mm/fault.c | 3 --- arch/openrisc/mm/fault.c | 1 - arch/parisc/mm/fault.c | 4 +--- arch/powerpc/mm/fault.c | 6 ------ arch/riscv/mm/fault.c | 5 ----- arch/s390/mm/fault.c | 5 +---- arch/sh/mm/fault.c | 1 - arch/sparc/mm/fault_32.c | 1 - arch/sparc/mm/fault_64.c | 1 - arch/um/kernel/trap.c | 1 - arch/unicore32/mm/fault.c | 4 +--- arch/x86/mm/fault.c | 2 -- arch/xtensa/mm/fault.c | 1 - drivers/gpu/drm/ttm/ttm_bo_vm.c | 12 ++++++++--- include/linux/mm.h | 37 +++++++++++++++++++++++++++++++++ mm/filemap.c | 2 +- mm/shmem.c | 2 +- 27 files changed, 52 insertions(+), 55 deletions(-) diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c index ab1d4212d658..e032d2d03012 100644 --- a/arch/alpha/mm/fault.c +++ b/arch/alpha/mm/fault.c @@ -170,7 +170,7 @@ do_page_fault(unsigned long address, unsigned long mmcsr, else current->min_flt++; if (fault & VM_FAULT_RETRY) { - flags &= ~FAULT_FLAG_ALLOW_RETRY; + flags |= FAULT_FLAG_TRIED; /* No need to up_read(&mm->mmap_sem) as we would * have already released it in __lock_page_or_retry diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c index 27adf4e608e4..bbcde83e010a 100644 --- a/arch/arc/mm/fault.c +++ b/arch/arc/mm/fault.c @@ -151,7 +151,6 @@ void do_page_fault(unsigned long address, struct pt_regs *regs) * retry state machine */ if (flags & FAULT_FLAG_ALLOW_RETRY) { - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; goto retry; } diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c index f00fb4eafe54..5f1fb46a37b0 100644 --- a/arch/arm/mm/fault.c +++ b/arch/arm/mm/fault.c @@ -320,9 +320,6 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs) regs, addr); } if (fault & VM_FAULT_RETRY) { - /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk - * of starvation. */ - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; goto retry; } diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 0d3fe0ea6a70..8c26097bcf0d 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -491,12 +491,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, return 0; } - /* - * Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk of - * starvation. - */ if (mm_flags & FAULT_FLAG_ALLOW_RETRY) { - mm_flags &= ~FAULT_FLAG_ALLOW_RETRY; mm_flags |= FAULT_FLAG_TRIED; goto retry; } diff --git a/arch/hexagon/mm/vm_fault.c b/arch/hexagon/mm/vm_fault.c index 88a2e5635bfb..a299d2142cbb 100644 --- a/arch/hexagon/mm/vm_fault.c +++ b/arch/hexagon/mm/vm_fault.c @@ -103,7 +103,6 @@ void do_page_fault(unsigned long address, long cause, struct pt_regs *regs) else current->min_flt++; if (fault & VM_FAULT_RETRY) { - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; goto retry; } diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c index 8d47acf50fda..7679e960c685 100644 --- a/arch/ia64/mm/fault.c +++ b/arch/ia64/mm/fault.c @@ -168,7 +168,6 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re else current->min_flt++; if (fault & VM_FAULT_RETRY) { - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; /* No need to up_read(&mm->mmap_sem) as we would diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c index 103f93ba8139..d4ef4fdf4de4 100644 --- a/arch/m68k/mm/fault.c +++ b/arch/m68k/mm/fault.c @@ -163,9 +163,6 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, else current->min_flt++; if (fault & VM_FAULT_RETRY) { - /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk - * of starvation. */ - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; /* diff --git a/arch/microblaze/mm/fault.c b/arch/microblaze/mm/fault.c index 8b0615eab4b6..9a359568f70a 100644 --- a/arch/microblaze/mm/fault.c +++ b/arch/microblaze/mm/fault.c @@ -237,7 +237,6 @@ void do_page_fault(struct pt_regs *regs, unsigned long address, else current->min_flt++; if (fault & VM_FAULT_RETRY) { - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; /* diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c index 48aac20a1ded..5eeea572ff3f 100644 --- a/arch/mips/mm/fault.c +++ b/arch/mips/mm/fault.c @@ -179,7 +179,6 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write, tsk->min_flt++; } if (fault & VM_FAULT_RETRY) { - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; /* diff --git a/arch/nds32/mm/fault.c b/arch/nds32/mm/fault.c index baa44f9d0b4a..954ca83d3289 100644 --- a/arch/nds32/mm/fault.c +++ b/arch/nds32/mm/fault.c @@ -243,7 +243,6 @@ void do_page_fault(unsigned long entry, unsigned long addr, 1, regs, addr); } if (fault & VM_FAULT_RETRY) { - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; /* No need to up_read(&mm->mmap_sem) as we would diff --git a/arch/nios2/mm/fault.c b/arch/nios2/mm/fault.c index f9f178484184..07f467577e77 100644 --- a/arch/nios2/mm/fault.c +++ b/arch/nios2/mm/fault.c @@ -158,9 +158,6 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long cause, else current->min_flt++; if (fault & VM_FAULT_RETRY) { - /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk - * of starvation. */ - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; /* diff --git a/arch/openrisc/mm/fault.c b/arch/openrisc/mm/fault.c index 8ba3696dd10c..e7dadbdb21b3 100644 --- a/arch/openrisc/mm/fault.c +++ b/arch/openrisc/mm/fault.c @@ -182,7 +182,6 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long address, else tsk->min_flt++; if (fault & VM_FAULT_RETRY) { - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; /* No need to up_read(&mm->mmap_sem) as we would diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c index 163dcb080c7b..c837da780a79 100644 --- a/arch/parisc/mm/fault.c +++ b/arch/parisc/mm/fault.c @@ -329,14 +329,12 @@ void do_page_fault(struct pt_regs *regs, unsigned long code, else current->min_flt++; if (fault & VM_FAULT_RETRY) { - flags &= ~FAULT_FLAG_ALLOW_RETRY; - /* * No need to up_read(&mm->mmap_sem) as we would * have already released it in __lock_page_or_retry * in mm/filemap.c. */ - + flags |= FAULT_FLAG_TRIED; goto retry; } } diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index d321a6c5fe62..321f24d0762f 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -588,13 +588,7 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address, * case. */ if (unlikely(fault & VM_FAULT_RETRY)) { - /* We retry only once */ if (flags & FAULT_FLAG_ALLOW_RETRY) { - /* - * Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk - * of starvation. - */ - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; if (is_user && signal_pending(current)) return 0; diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c index ea8f301de65b..d1710ef75432 100644 --- a/arch/riscv/mm/fault.c +++ b/arch/riscv/mm/fault.c @@ -143,11 +143,6 @@ asmlinkage void do_page_fault(struct pt_regs *regs) 1, regs, addr); } if (fault & VM_FAULT_RETRY) { - /* - * Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk - * of starvation. - */ - flags &= ~(FAULT_FLAG_ALLOW_RETRY); flags |= FAULT_FLAG_TRIED; /* diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 3ad77501deef..46ef1159d146 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -514,10 +514,7 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) fault = VM_FAULT_PFAULT; goto out_up; } - /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk - * of starvation. */ - flags &= ~(FAULT_FLAG_ALLOW_RETRY | - FAULT_FLAG_RETRY_NOWAIT); + flags &= ~FAULT_FLAG_RETRY_NOWAIT; flags |= FAULT_FLAG_TRIED; down_read(&mm->mmap_sem); goto retry; diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c index f620282a37fd..2e9cf3fd395f 100644 --- a/arch/sh/mm/fault.c +++ b/arch/sh/mm/fault.c @@ -481,7 +481,6 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, regs, address); } if (fault & VM_FAULT_RETRY) { - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; /* diff --git a/arch/sparc/mm/fault_32.c b/arch/sparc/mm/fault_32.c index 9af0c3ad50d6..97494086f1e5 100644 --- a/arch/sparc/mm/fault_32.c +++ b/arch/sparc/mm/fault_32.c @@ -261,7 +261,6 @@ asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write, 1, regs, address); } if (fault & VM_FAULT_RETRY) { - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; /* No need to up_read(&mm->mmap_sem) as we would diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c index 566f05f9040b..a1730c3a8f30 100644 --- a/arch/sparc/mm/fault_64.c +++ b/arch/sparc/mm/fault_64.c @@ -446,7 +446,6 @@ asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs) 1, regs, address); } if (fault & VM_FAULT_RETRY) { - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; /* No need to up_read(&mm->mmap_sem) as we would diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c index 3c72111f27e9..063da0930d31 100644 --- a/arch/um/kernel/trap.c +++ b/arch/um/kernel/trap.c @@ -98,7 +98,6 @@ int handle_page_fault(unsigned long address, unsigned long ip, else current->min_flt++; if (fault & VM_FAULT_RETRY) { - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; goto retry; diff --git a/arch/unicore32/mm/fault.c b/arch/unicore32/mm/fault.c index 04c193439c97..8b3367ec0d80 100644 --- a/arch/unicore32/mm/fault.c +++ b/arch/unicore32/mm/fault.c @@ -260,9 +260,7 @@ static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs) else tsk->min_flt++; if (fault & VM_FAULT_RETRY) { - /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk - * of starvation. */ - flags &= ~FAULT_FLAG_ALLOW_RETRY; + flags |= FAULT_FLAG_TRIED; goto retry; } } diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index f7836472961e..7664f0f89ef6 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1447,9 +1447,7 @@ void do_user_addr_fault(struct pt_regs *regs, * that we made any progress. Handle this case first. */ if (unlikely(fault & VM_FAULT_RETRY)) { - /* Retry at most once */ if (flags & FAULT_FLAG_ALLOW_RETRY) { - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; if ((flags & FAULT_FLAG_USER) && signal_pending(tsk)) return; diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c index 094606676c36..1d91a23d27d3 100644 --- a/arch/xtensa/mm/fault.c +++ b/arch/xtensa/mm/fault.c @@ -129,7 +129,6 @@ void do_page_fault(struct pt_regs *regs) else current->min_flt++; if (fault & VM_FAULT_RETRY) { - flags &= ~FAULT_FLAG_ALLOW_RETRY; flags |= FAULT_FLAG_TRIED; /* No need to up_read(&mm->mmap_sem) as we would diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c index 6dacff49c1cc..8f2f9ee6effa 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c @@ -61,9 +61,10 @@ static vm_fault_t ttm_bo_vm_fault_idle(struct ttm_buffer_object *bo, /* * If possible, avoid waiting for GPU with mmap_sem - * held. + * held. We only do this if the fault allows retry and this + * is the first attempt. */ - if (vmf->flags & FAULT_FLAG_ALLOW_RETRY) { + if (fault_flag_allow_retry_first(vmf->flags)) { ret = VM_FAULT_RETRY; if (vmf->flags & FAULT_FLAG_RETRY_NOWAIT) goto out_unlock; @@ -132,7 +133,12 @@ static vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf) * for the buffer to become unreserved. */ if (unlikely(!reservation_object_trylock(bo->resv))) { - if (vmf->flags & FAULT_FLAG_ALLOW_RETRY) { + /* + * If the fault allows retry and this is the first + * fault attempt, we try to release the mmap_sem + * before waiting + */ + if (fault_flag_allow_retry_first(vmf->flags)) { if (!(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) { ttm_bo_get(bo); up_read(&vmf->vma->vm_mm->mmap_sem); diff --git a/include/linux/mm.h b/include/linux/mm.h index 53ec7abb8472..0fdbdcb257d6 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -396,6 +396,25 @@ extern pgprot_t protection_map[16]; * @FAULT_FLAG_REMOTE: The fault is not for current task/mm. * @FAULT_FLAG_INSTRUCTION: The fault was during an instruction fetch. * @FAULT_FLAG_INTERRUPTIBLE: The fault can be interrupted by non-fatal signals. + * + * About @FAULT_FLAG_ALLOW_RETRY and @FAULT_FLAG_TRIED: we can specify + * whether we would allow page faults to retry by specifying these two + * fault flags correctly. Currently there can be three legal combinations: + * + * (a) ALLOW_RETRY and !TRIED: this means the page fault allows retry, and + * this is the first try + * + * (b) ALLOW_RETRY and TRIED: this means the page fault allows retry, and + * we've already tried at least once + * + * (c) !ALLOW_RETRY and !TRIED: this means the page fault does not allow retry + * + * The unlisted combination (!ALLOW_RETRY && TRIED) is illegal and should never + * be used. Note that page faults can be allowed to retry for multiple times, + * in which case we'll have an initial fault with flags (a) then later on + * continuous faults with flags (b). We should always try to detect pending + * signals before a retry to make sure the continuous page faults can still be + * interrupted if necessary. */ #define FAULT_FLAG_WRITE 0x01 #define FAULT_FLAG_MKWRITE 0x02 @@ -416,6 +435,24 @@ extern pgprot_t protection_map[16]; FAULT_FLAG_KILLABLE | \ FAULT_FLAG_INTERRUPTIBLE) +/** + * fault_flag_allow_retry_first - check ALLOW_RETRY the first time + * + * This is mostly used for places where we want to try to avoid taking + * the mmap_sem for too long a time when waiting for another condition + * to change, in which case we can try to be polite to release the + * mmap_sem in the first round to avoid potential starvation of other + * processes that would also want the mmap_sem. + * + * Return: true if the page fault allows retry and this is the first + * attempt of the fault handling; false otherwise. + */ +static inline bool fault_flag_allow_retry_first(unsigned int flags) +{ + return (flags & FAULT_FLAG_ALLOW_RETRY) && + (!(flags & FAULT_FLAG_TRIED)); +} + #define FAULT_FLAG_TRACE \ { FAULT_FLAG_WRITE, "WRITE" }, \ { FAULT_FLAG_MKWRITE, "MKWRITE" }, \ diff --git a/mm/filemap.c b/mm/filemap.c index d0cf700bf201..543404617f5a 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1399,7 +1399,7 @@ EXPORT_SYMBOL_GPL(__lock_page_killable); int __lock_page_or_retry(struct page *page, struct mm_struct *mm, unsigned int flags) { - if (flags & FAULT_FLAG_ALLOW_RETRY) { + if (fault_flag_allow_retry_first(flags)) { /* * CAUTION! In this case, mmap_sem is not released * even though return 0. diff --git a/mm/shmem.c b/mm/shmem.c index 626d8c74b973..c32e7101294e 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2011,7 +2011,7 @@ static vm_fault_t shmem_fault(struct vm_fault *vmf) DEFINE_WAIT_FUNC(shmem_fault_wait, synchronous_wake_function); ret = VM_FAULT_NOPAGE; - if ((vmf->flags & FAULT_FLAG_ALLOW_RETRY) && + if (fault_flag_allow_retry_first(vmf->flags) && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) { /* It's polite to up mmap_sem if we can */ up_read(&vma->vm_mm->mmap_sem); From patchwork Thu Sep 5 10:15:34 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 11132639 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C6D8F1709 for ; Thu, 5 Sep 2019 10:16:45 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9DBFB21743 for ; Thu, 5 Sep 2019 10:16:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9DBFB21743 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BBA616B0282; Thu, 5 Sep 2019 06:16:44 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id B44C96B0283; Thu, 5 Sep 2019 06:16:44 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A0BA26B0284; Thu, 5 Sep 2019 06:16:44 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0050.hostedemail.com [216.40.44.50]) by kanga.kvack.org (Postfix) with ESMTP id 7DC6D6B0282 for ; Thu, 5 Sep 2019 06:16:44 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id E8676180AD7C3 for ; Thu, 5 Sep 2019 10:16:43 +0000 (UTC) X-FDA: 75900463086.25.books08_57d109e4dd215 X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,peterx@redhat.com,::linux-kernel@vger.kernel.org:david@redhat.com:hughd@google.com:gokhale2@llnl.gov:jglisse@redhat.com:xemul@virtuozzo.com:hannes@cmpxchg.org:peterx@redhat.com:cracauer@cons.org:mcfadden8@llnl.gov:shli@fb.com:aarcange@redhat.com:mike.kravetz@oracle.com:dplotnikov@virtuozzo.com:rppt@linux.vnet.ibm.com:torvalds@linux-foundation.org:mgorman@suse.de:kirill@shutemov.name:dgilbert@redhat.com,RULES_HIT:30054:30070,0,RBL:209.132.183.28:@redhat.com:.lbl8.mailshell.net-62.18.0.0 64.10.201.10,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:ft,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:1,LUA_SUMMARY:none X-HE-Tag: books08_57d109e4dd215 X-Filterd-Recvd-Size: 5546 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by imf35.hostedemail.com (Postfix) with ESMTP for ; Thu, 5 Sep 2019 10:16:43 +0000 (UTC) Received: from mail-pl1-f198.google.com (mail-pl1-f198.google.com [209.85.214.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7411AA76C for ; Thu, 5 Sep 2019 10:16:42 +0000 (UTC) Received: by mail-pl1-f198.google.com with SMTP id f5so1193885plr.0 for ; Thu, 05 Sep 2019 03:16:42 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ZxGn2ZdCmZxu7XSt21NyGW/6BPjnqeicp2jG9/gg754=; b=WoT+nbSRcEJNvkKy7IoJgqONvgAZGEDLkpxYPb8T0AzgIajjpkwsUGYTwbPN4afMTA 8dW1Yx8WNMWY0RqrgCOCO8+L4c26xywOFSgiDJuIGW6f/DfX3eUt8kWjNPeVuAhUzWLy XqGHB5G63JKjaY7kkEyY4HtxMT5yAsyVrAdcIlsFG1fRG54JUCdEEjYKPat0HnCA8iRV 9hcP2rxbQTRW8mqI2rG4kTy4r9uA//E4avyqC/Bb8Ry/E6NXhi0GhE2nQ6qbBBeF7e+H HzsHETRHsnxGTgy74BkbI9cUQ9tqLJmO3smn01gOJih3nFdhFqd6hmz3akZShZydEjOE MjrA== X-Gm-Message-State: APjAAAVV1Mp4VSUx5dlc0m/RiL2x6/LsF/3x4r45hZ8hiFe3lDit0G6P co4ymO+uO7dm5/SKunRR7FbJn2HihPzUDdFiBIxIWbvR2TGFMXRFVb/ud9BHDlgYqmCdOm4Jo6E tHovLD9qudwU= X-Received: by 2002:a63:4c5a:: with SMTP id m26mr2400208pgl.270.1567678601199; Thu, 05 Sep 2019 03:16:41 -0700 (PDT) X-Google-Smtp-Source: APXvYqyKY6zyOi9KJwWuM85hdo9q/xf5YhRviK2C6aqVXRBBcdCiehlIc9Px5hIh14dORwxN2WooCg== X-Received: by 2002:a63:4c5a:: with SMTP id m26mr2400188pgl.270.1567678600925; Thu, 05 Sep 2019 03:16:40 -0700 (PDT) Received: from xz-x1.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id a20sm413852pfo.33.2019.09.05.03.16.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Sep 2019 03:16:39 -0700 (PDT) From: Peter Xu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: David Hildenbrand , Hugh Dickins , Maya Gokhale , Jerome Glisse , Pavel Emelyanov , Johannes Weiner , peterx@redhat.com, Martin Cracauer , Marty McFadden , Shaohua Li , Andrea Arcangeli , Mike Kravetz , Denis Plotnikov , Mike Rapoport , Linus Torvalds , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" Subject: [PATCH v2 7/7] mm/gup: Allow VM_FAULT_RETRY for multiple times Date: Thu, 5 Sep 2019 18:15:34 +0800 Message-Id: <20190905101534.9637-8-peterx@redhat.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190905101534.9637-1-peterx@redhat.com> References: <20190905101534.9637-1-peterx@redhat.com> MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This is the gup counterpart of the change that allows the VM_FAULT_RETRY to happen for more than once. Reviewed-by: Jerome Glisse Signed-off-by: Peter Xu --- mm/gup.c | 17 +++++++++++++---- mm/hugetlb.c | 6 ++++-- 2 files changed, 17 insertions(+), 6 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index eddbb95dcb8f..65d0b45be5c9 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -644,7 +644,10 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma, if (*flags & FOLL_NOWAIT) fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT; if (*flags & FOLL_TRIED) { - VM_WARN_ON_ONCE(fault_flags & FAULT_FLAG_ALLOW_RETRY); + /* + * Note: FAULT_FLAG_ALLOW_RETRY and FAULT_FLAG_TRIED + * can co-exist + */ fault_flags |= FAULT_FLAG_TRIED; } @@ -1059,17 +1062,23 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk, if (likely(pages)) pages += ret; start += ret << PAGE_SHIFT; + lock_dropped = true; +retry: /* * Repeat on the address that fired VM_FAULT_RETRY - * without FAULT_FLAG_ALLOW_RETRY but with + * with both FAULT_FLAG_ALLOW_RETRY and * FAULT_FLAG_TRIED. */ *locked = 1; - lock_dropped = true; down_read(&mm->mmap_sem); ret = __get_user_pages(tsk, mm, start, 1, flags | FOLL_TRIED, - pages, NULL, NULL); + pages, NULL, locked); + if (!*locked) { + /* Continue to retry until we succeeded */ + BUG_ON(ret != 0); + goto retry; + } if (ret != 1) { BUG_ON(ret > 1); if (!pages_done) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 5f816ee42206..6b9d27925e7a 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4328,8 +4328,10 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT; if (flags & FOLL_TRIED) { - VM_WARN_ON_ONCE(fault_flags & - FAULT_FLAG_ALLOW_RETRY); + /* + * Note: FAULT_FLAG_ALLOW_RETRY and + * FAULT_FLAG_TRIED can co-exist + */ fault_flags |= FAULT_FLAG_TRIED; } ret = hugetlb_fault(mm, vma, vaddr, fault_flags);