From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by sourceware.org (Postfix) with ESMTPS id 2CF1B3846027 for ; Tue, 8 Jun 2021 11:45:23 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 2CF1B3846027 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: sourceware.org; spf=none smtp.mailfrom=infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=wnXuDaSzTGYZ5h0WV9tmuYOo7bwrW3p7q5WO8BPzujQ=; b=Ys2vp0Pk9YGzIFdmF6/EtYp9ed Mpc9y6acdYj3N7S3SWQqOvs0pSlHbfao7WQAtu5/3aN6UFQy3Rbkw3zXHIE8yIuAnArBGtj0d0djU 9EnIuw/wdRfosmUxwdgo6P9M5ufMH5zo9ELO91ja08AZNYdLAYhAXaM1ZRwjLrsxXcG8rdm/SUcpo fULa/yWmHHYq7mfntXLdLjg9cmMab8YOlWs751AIXE6X9nOCgMnWiX6ufj0gM67RZFd8lNCIg6sk9 rjaBRdd0qrwF1L9GlQ7jf83j+A3uFTAfBIf7IObg1HDb9WKqDlO9JIu6LIoBsXuyXNIBDvKcUMGes oO0tdx3A==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqa9w-004jsb-CJ; Tue, 08 Jun 2021 11:44:47 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 03BF830018A; Tue, 8 Jun 2021 13:44:44 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id C2BF52011672D; Tue, 8 Jun 2021 13:44:44 +0200 (CEST) Date: Tue, 8 Jun 2021 13:44:44 +0200 From: Peter Zijlstra To: Greg KH Cc: Andrey Semashev , Nicholas Piggin , =?iso-8859-1?Q?Andr=E9?= Almeida , acme@kernel.org, Sebastian Andrzej Siewior , corbet@lwn.net, Davidlohr Bueso , Darren Hart , fweimer@redhat.com, joel@joelfernandes.org, kernel@collabora.com, krisman@collabora.com, libc-alpha@sourceware.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, malteskarupke@fastmail.fm, Ingo Molnar , pgriffais@valvesoftware.com, Peter Oskolkov , Steven Rostedt , shuah@kernel.org, Thomas Gleixner , z.figura12@gmail.com Subject: Re: [PATCH v4 00/15] Add futex2 syscalls Message-ID: References: <20210603195924.361327-1-andrealmeid@collabora.com> <1622799088.hsuspipe84.astroid@bobo.none> <1622853816.mokf23xgnt.astroid@bobo.none> <6d8e3bb4-0cef-b991-9a16-1f03d10f131d@gmail.com> <1622980258.cfsuodze38.astroid@bobo.none> <1623114630.pc8fq7r5y9.astroid@bobo.none> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=1.3 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_ABUSEAT, RCVD_IN_SBL_CSS, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=no autolearn_force=no version=3.4.2 X-Spam-Level: * X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Jun 2021 11:45:34 -0000 On Tue, Jun 08, 2021 at 01:13:30PM +0200, Greg KH wrote: > On Tue, Jun 08, 2021 at 02:03:50PM +0300, Andrey Semashev wrote: > So what's keeping the futex2 code from doing all that futex1 does so > that the futex1 code can be deleted internally? I'd much rather see it the other way around. Much of what futex2 does can already be done with the futex1 code-base. And then we can add features on top. I've been moaning about this for the past many versions, even older versions actually implemented some of the new features in futex1, showing it can be done. We just wanted a saner futex interface because the existing futex syscall is a monster and making it even worse seemed like a bad idea. So *again*: please add the new syscalls on top of futex1 and then extend. Do not re-implement.