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[209.85.208.176]) by smtp.gmail.com with ESMTPSA id y6sm2549369lfh.106.2020.09.27.12.36.15 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 27 Sep 2020 12:36:16 -0700 (PDT) Received: by mail-lj1-f176.google.com with SMTP id u21so6577108ljl.6 for ; Sun, 27 Sep 2020 12:36:15 -0700 (PDT) X-Received: by 2002:a05:651c:104c:: with SMTP id x12mr4346496ljm.285.1601235375523; Sun, 27 Sep 2020 12:36:15 -0700 (PDT) MIME-Version: 1.0 References: <20200925222600.6832-1-peterx@redhat.com> In-Reply-To: <20200925222600.6832-1-peterx@redhat.com> From: Linus Torvalds Date: Sun, 27 Sep 2020 12:35:59 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 0/4] mm: Break COW for pinned pages during fork() To: Peter Xu Cc: Linux Kernel Mailing List , Linux-MM , Jason Gunthorpe , John Hubbard , Andrew Morton , Christoph Hellwig , Yang Shi , Oleg Nesterov , Kirill Tkhai , Kirill Shutemov , Hugh Dickins , Jann Horn , Michal Hocko , Jan Kara , Andrea Arcangeli , Leon Romanovsky 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 Fri, Sep 25, 2020 at 3:26 PM Peter Xu wrote: > > This series is majorly inspired by the previous discussion on the list [1], > starting from the report from Jason on the rdma test failure. Ok, this is now in my git tree with the changes I outlined in the other email. > I tested it myself with fork() after vfio pinning a bunch of device pages, .. but _my_ only testing was to just add a nasty hack that said that all pages are pinned, and made fork() much slower, but hey, it at least tests the preallocation paths etc. And I'm not seeing any obvious failures due to taking that slow-path that is supposed to be a special case. Let's hope this closes the rdma issues. Linus