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([2620:15c:2c1:200:55c7:81e6:c7d8:94b]) by smtp.gmail.com with ESMTPSA id u62-v6sm53459766pfu.69.2018.11.01.09.59.38 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 01 Nov 2018 09:59:39 -0700 (PDT) Subject: Re: [RFC PATCH] lib: Introduce generic __cmpxchg_u64() and use it where needed To: Peter Zijlstra , Trond Myklebust Cc: "mark.rutland@arm.com" , "linux-kernel@vger.kernel.org" , "ralf@linux-mips.org" , "jlayton@kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "bfields@fieldses.org" , "linux-mips@linux-mips.org" , "linux@roeck-us.net" , "linux-nfs@vger.kernel.org" , "akpm@linux-foundation.org" , "will.deacon@arm.com" , "boqun.feng@gmail.com" , "paul.burton@mips.com" , "anna.schumaker@netapp.com" , "jhogan@kernel.org" , "netdev@vger.kernel.org" , "davem@davemloft.net" , "arnd@arndb.de" , "paulus@samba.org" , "mpe@ellerman.id.au" , "benh@kernel.crashing.org" , Paul McKenney , aryabinin@virtuozzo.com, dvyukov@google.com References: <1541015538-11382-1-git-send-email-linux@roeck-us.net> <20181031213240.zhh7dfcm47ucuyfl@pburton-laptop> <20181031220253.GA15505@roeck-us.net> <20181031233235.qbedw3pinxcuk7me@pburton-laptop> <4e2438a23d2edf03368950a72ec058d1d299c32e.camel@hammerspace.com> <20181101131846.biyilr2msonljmij@lakrids.cambridge.arm.com> <20181101145926.GE3178@hirez.programming.kicks-ass.net> <20181101163212.GF3159@hirez.programming.kicks-ass.net> From: Eric Dumazet Message-ID: Date: Thu, 1 Nov 2018 09:59:38 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20181101163212.GF3159@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On 11/01/2018 09:32 AM, Peter Zijlstra wrote: >> Anyhow, if the atomic maintainers are willing to stand up and state for >> the record that the atomic counters are guaranteed to wrap modulo 2^n >> just like unsigned integers, then I'm happy to take Paul's patch. > > I myself am certainly relying on it. Could we get uatomic_t support maybe ? This reminds me of this sooooo silly patch :/ https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=adb03115f4590baa280ddc440a8eff08a6be0cb7