From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753979Ab2LYPng (ORCPT ); Tue, 25 Dec 2012 10:43:36 -0500 Received: from mailhub.sw.ru ([195.214.232.25]:30520 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753861Ab2LYPnd (ORCPT ); Tue, 25 Dec 2012 10:43:33 -0500 Message-ID: <50D9C8E9.6020602@parallels.com> Date: Tue, 25 Dec 2012 19:40:25 +0400 From: Pavel Emelyanov User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120605 Thunderbird/13.0 MIME-Version: 1.0 To: Oleg Nesterov CC: Andrey Wagin , linux-kernel@vger.kernel.org, criu@openvz.org, linux-fsdevel@vger.kernel.org, Alexander Viro , "Paul E. McKenney" , David Howells , Thomas Gleixner , Michael Kerrisk , Cyrill Gorcunov Subject: Re: [PATCH 1/4] signalfd: add ability to return siginfo in a raw format References: <1356336807-5517-1-git-send-email-avagin@openvz.org> <1356336807-5517-2-git-send-email-avagin@openvz.org> <20121224165306.GA9553@redhat.com> <20121225143043.GA1813@redhat.com> <20121225152716.GA3198@redhat.com> In-Reply-To: <20121225152716.GA3198@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/25/2012 07:27 PM, Oleg Nesterov wrote: > On 12/25, Oleg Nesterov wrote: >> >> And if we add another format we should think >> twice. > > And btw this applies to the whole series. > > I guess that probably you actually need DUMP, not DEQUEUE. but the > latter is not trivial. However, perhaps we can do this assuming that > all other threads are sleeping and nobody can do dequeue_signal(). > Say, we can play with ppos/llseek. If *ppos is not zero, > signalfd_dequeue() could dump the nth entry from list or return 0. This would be perfect, but isn't it better to preserve the pos semantics -- we do know size of entry we're about to copy, we can treat pos as offset in bytes, not in elements. > Oleg. > > . >