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[209.85.221.52]) by smtp.gmail.com with ESMTPSA id i24-20020a05640200d800b0042dcac2afc6sm4234309edu.72.2022.06.17.12.48.25 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 17 Jun 2022 12:48:25 -0700 (PDT) Received: by mail-wr1-f52.google.com with SMTP id q9so6954106wrd.8 for ; Fri, 17 Jun 2022 12:48:25 -0700 (PDT) X-Received: by 2002:a05:6000:16c4:b0:20f:cd5d:4797 with SMTP id h4-20020a05600016c400b0020fcd5d4797mr10819451wrf.193.1655495305221; Fri, 17 Jun 2022 12:48:25 -0700 (PDT) MIME-Version: 1.0 References: <20220617091039.2257083-1-eric.dumazet@gmail.com> <2dd754f9-3a79-ed17-e423-6b411c3afb69@redhat.com> <2730b855-8f99-5a9e-707e-697d3bd9811d@redhat.com> <7499dd05-30d1-669c-66b4-5cb06452b476@redhat.com> In-Reply-To: From: Linus Torvalds Date: Fri, 17 Jun 2022 14:48:08 -0500 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] locking/rwlocks: do not starve writers To: Eric Dumazet Cc: Peter Zijlstra , Waiman Long , Shakeel Butt , Eric Dumazet , linux-kernel , Ingo Molnar , Boqun Feng , Will Deacon , Roman Penyaev Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-1.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 17, 2022 at 2:39 PM Eric Dumazet wrote: > > I am converting RAW sockets to RCU. RCU is usually absolutely the best approach. Use regular spinlocks for writers, and RCU for readers. I'd love to see the tasklist_lock be converted to RCU too. But that locks predates RCU (and probably 99% of all kernel code), and it's messy, so nobody sane has ever willingly tried to do that afaik. Linus