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[209.85.167.42]) by smtp.gmail.com with ESMTPSA id w10sm2542353lfe.107.2021.01.09.17.04.03 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 09 Jan 2021 17:04:03 -0800 (PST) Received: by mail-lf1-f42.google.com with SMTP id x20so32214818lfe.12 for ; Sat, 09 Jan 2021 17:04:03 -0800 (PST) X-Received: by 2002:a19:8557:: with SMTP id h84mr4187473lfd.201.1610240165669; Sat, 09 Jan 2021 16:56:05 -0800 (PST) MIME-Version: 1.0 References: <20210110004435.26382-1-aarcange@redhat.com> In-Reply-To: <20210110004435.26382-1-aarcange@redhat.com> From: Linus Torvalds Date: Sat, 9 Jan 2021 16:55:49 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 0/1] mm: restore full accuracy in COW page reuse To: Andrea Arcangeli Cc: Andrew Morton , Linux-MM , Linux Kernel Mailing List , Yu Zhao , Andy Lutomirski , Peter Xu , Pavel Emelyanov , Mike Kravetz , Mike Rapoport , Minchan Kim , Will Deacon , Peter Zijlstra , Hugh Dickins , "Kirill A. Shutemov" , Matthew Wilcox , Oleg Nesterov , Jann Horn , Kees Cook , John Hubbard , Leon Romanovsky , Jason Gunthorpe , Jan Kara , Kirill Tkhai , Nadav Amit , Jens Axboe Content-Type: text/plain; charset="UTF-8" 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: On Sat, Jan 9, 2021 at 4:44 PM Andrea Arcangeli wrote: > > Once we agree that COW page reuse requires full accuracy, [...] You have completely and utterly ignored every single argument against that. Instead, you just continue to push your agenda. The thing is, GUP works fine. COW works fine. The thing that is broken is clear_refs. Yet you try to now "fix" the two fine cases, because you don't want to fix clear_refs. What part of "clear_refs is the _least_ important of the three cases" are you not willing to understand? Linus