Received: by 2002:a05:6902:102b:0:0:0:0 with SMTP id x11csp3307276ybt; Sat, 4 Jul 2020 12:31:12 -0700 (PDT) X-Google-Smtp-Source: ABdhPJx6ECX2M1GzTy9EhdjnP5AimtkMYQ4r17McTrgqJHmCdQiOHCNGTf08nK5gSg81GeGbfxUq X-Received: by 2002:a50:acc5:: with SMTP id x63mr24887107edc.99.1593891072256; Sat, 04 Jul 2020 12:31:12 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1593891072; cv=none; d=google.com; s=arc-20160816; b=KMwppgFdib6fGhOQB5dWqzDwWk82RTlfZCJCSRSgKNGf/OvDPG4uu6+z5NrkZyx3ex zxTfAhIDNm3ZWYKPop6Wz9YVqwBVit3vbsmTGDvd5xm/E1koNp2FrwkzRV2ZmKGy3d8q hz3OK5XTV964Ev4PbIau9g0pM5okf2WKmy06UvQYdA7J+krIk7sNQjicIektjZ5pRjja OQumjsWwf89FOYJYh34aJmN+tv7OQeMke3b7V9L9U+e7E71aMsXkMASYq7cWJLjARiMx 526Q0JHomteYdOtjGiM/LsuWTsJlFZb8bwCNC/XzlTSulre/3pnQkz3lBgVQy7Jorn1h 1lTQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:in-reply-to:content-disposition :mime-version:references:message-id:subject:cc:to:from:date; bh=qbBpywF97L36aeAqUL0W/GE01iS0bu/0koSEKWi3naU=; b=J7TQbZdlcsWfCaEi4n1t/zux4mDe1JrUP7KXRAV69kE5f64kqsdu2CKoFGgTThG/VO g/8fERXCJGosMcEoD2a8nh4mUHSN1q/RM6XYaV38HKacMjJh5Ex/gYkDOVObyaSe60/X KZ8QfywxRxc3A/xKLLBWjdh8Qqhqc5C9QOCbGVSahTguiGBT0YuKxr2VPI9D6hZA5KiR ZKVsQsvElneulWANvvOttSvRSDai+zlNANkq8lrMroiXx0LuLfZpHT0NIdRhP29l9ihv eZHP/YjJqRMmvyrN1zv0u+TsnY7SnwfZTLlGbvPIVGibzBVO6duQMtokPH3jNrWuJIFQ xrFQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id j28si11197337edj.142.2020.07.04.12.30.49; Sat, 04 Jul 2020 12:31:12 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727835AbgGDTaq (ORCPT + 99 others); Sat, 4 Jul 2020 15:30:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56236 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726643AbgGDTaq (ORCPT ); Sat, 4 Jul 2020 15:30:46 -0400 Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [IPv6:2002:c35c:fd02::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EE122C061794; Sat, 4 Jul 2020 12:30:45 -0700 (PDT) Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jrns0-005NRw-HY; Sat, 04 Jul 2020 19:30:40 +0000 Date: Sat, 4 Jul 2020 20:30:40 +0100 From: Al Viro To: Greg Kroah-Hartman Cc: mtk.manpages@gmail.com, shuah@kernel.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-man@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH 0/3] readfile(2): a new syscall to make open/read/close faster Message-ID: <20200704193040.GC2786714@ZenIV.linux.org.uk> References: <20200704140250.423345-1-gregkh@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200704140250.423345-1-gregkh@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jul 04, 2020 at 04:02:46PM +0200, Greg Kroah-Hartman wrote: > Here is a tiny new syscall, readfile, that makes it simpler to read > small/medium sized files all in one shot, no need to do open/read/close. > This is especially helpful for tools that poke around in procfs or > sysfs, making a little bit of a less system load than before, especially > as syscall overheads go up over time due to various CPU bugs being > addressed. Nice series, but you are 3 months late with it... Next AFD, perhaps? Seriously, the rationale is bollocks. If the overhead of 2 extra syscalls is anywhere near the costs of the real work being done by that thing, we have already lost and the best thing to do is to throw the system away and start with saner hardware.