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[209.85.160.174]) by smtp.gmail.com with ESMTPSA id b3-20020ac86bc3000000b003ab7aee56a0sm4647335qtt.39.2023.01.09.06.34.21 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 09 Jan 2023 06:34:21 -0800 (PST) Received: by mail-qt1-f174.google.com with SMTP id c7so7873285qtw.8 for ; Mon, 09 Jan 2023 06:34:21 -0800 (PST) X-Received: by 2002:ae9:ef49:0:b0:6fe:d4a6:dcef with SMTP id d70-20020ae9ef49000000b006fed4a6dcefmr3220519qkg.594.1673274554214; Mon, 09 Jan 2023 06:29:14 -0800 (PST) MIME-Version: 1.0 References: <20230101162910.710293-1-Jason@zx2c4.com> <20230101162910.710293-3-Jason@zx2c4.com> <874jt0kndq.fsf@oldenburg.str.redhat.com> In-Reply-To: <874jt0kndq.fsf@oldenburg.str.redhat.com> From: Linus Torvalds Date: Mon, 9 Jan 2023 08:28:58 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v14 2/7] mm: add VM_DROPPABLE for designating always lazily freeable mappings To: Florian Weimer Cc: "Jason A. Donenfeld" , Andy Lutomirski , Ingo Molnar , linux-kernel@vger.kernel.org, patches@lists.linux.dev, tglx@linutronix.de, linux-crypto@vger.kernel.org, linux-api@vger.kernel.org, x86@kernel.org, Greg Kroah-Hartman , Adhemerval Zanella Netto , "Carlos O'Donell" , Arnd Bergmann , Jann Horn , Christian Brauner , linux-mm@kvack.org, mlichvar@redhat.com Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: AD667180002 X-Stat-Signature: fh4qp3siorwz4bq6d6pqiaf1pi73pjw5 X-HE-Tag: 1673274863-123850 X-HE-Meta: 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 Mwfz9LHq SnOaTIbPDp2/Wu1xv5rZLDs4mzzPRpwTU6KxVnPnQ1LggC1/jznTdQnZipFaFdIU0OSQAJN9nyFsOfP1ct4AsBwW9YMjlDGKCZ/nEIlOOIoC60u5QREg33ilCCXr6raqczmjJK4Rs8Ab2bo2OJOKMDOsOD6qsapZYWTHHcr6M8evNkU55mKVcc7R6dQ1teJIp9cC+6O5mYSgh9GMT9tAfWm9iIt/cTDfZ6pm0l9zqrydKMBc0rY3WeDJA/YmdpvDyM4IQ9FAmlsuf/pQHq3TiTOPwYOpMyW3IyyUxWXW/Q0XitLahjBukNj1yH56wlzcY8GEDUYY1jh+bjQdguKEVvrj3IA== 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 Mon, Jan 9, 2023 at 4:34 AM Florian Weimer wrote: > > We did these changes on the glibc side because Jason sounded very > confident that he's able to deliver vDSO acceleration for getrandom. If > that fails to materialize, we'll just have to add back userspace > buffering in glibc. My whole argument has been that user-space buffering is the sane thing to do. Most definitely for something like glibc. The number of people who go "oh, no, my buffer or randomness could be exposed by insert-odd-situation-here" is approximately zero, and then the onus should be on *them* to do something special. Because *they* are special. Precious little snowflake special. Linus