Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752708Ab0HTIh1 (ORCPT ); Fri, 20 Aug 2010 04:37:27 -0400 Received: from shutemov.name ([188.40.19.243]:34493 "EHLO shutemov.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751202Ab0HTIhY (ORCPT ); Fri, 20 Aug 2010 04:37:24 -0400 Date: Fri, 20 Aug 2010 11:37:23 +0300 From: "Kirill A. Shutemov" To: Greg KH Cc: Andrew Morton , "H. Peter Anvin" , Alexander Shishkin , Thomas Gleixner , John Stultz , Martin Schwidefsky , Jon Hunter , Ingo Molnar , Peter Zijlstra , "Paul E. McKenney" , David Howells , Avi Kivity , John Kacur , Chris Friesen , Kay Sievers , linux-kernel@vger.kernel.org Subject: Re: [PATCH] [RFCv2] notify userspace about time changes Message-ID: <20100820083723.GA18616@shutemov.name> References: <1282139739-23832-1-git-send-email-virtuoso@slind.org> <20100818155702.bc62b2a6.akpm@linux-foundation.org> <4C6C7034.4050501@zytor.com> <20100818165303.dd52695a.akpm@linux-foundation.org> <20100819040937.GA8646@suse.de> <20100819083612.GA13293@shutemov.name> <20100819153127.GC2985@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100819153127.GC2985@suse.de> User-Agent: Mutt/1.5.20 (2010-08-04) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1878 Lines: 48 On Thu, Aug 19, 2010 at 08:31:27AM -0700, Greg KH wrote: > On Thu, Aug 19, 2010 at 11:36:12AM +0300, Kirill A. Shutemov wrote: > > On Wed, Aug 18, 2010 at 09:09:37PM -0700, Greg KH wrote: > > > On Wed, Aug 18, 2010 at 04:53:03PM -0700, Andrew Morton wrote: > > > > Is sysfs the right interface for this thing? Bear in mind that > > > > CONFIG_SYSFS does exist. > > > > > > > > > + fd = open("/sys/kernel/time_notify", O_WRONLY); > > > > > + fdprintf(fd, "%d 1 0 1 1", efd); > > > > > > > > why not > > > > > > > > sys_time_notify(efd, 1, 0, 1, 1); > > > > > > Yeah, that would be much better than a sysfs file, this is abusing the > > > sysfs interface quite a lot. > > > > Do you really think, that increasing number of syscalls is better then > > fs-based interfaces? > > As you are pretty much creating a new syscall here anyway, there is no > problem with making it a real one, right? I think Linux has too many syscalls. Significant part these interfaces would be better to map to a filesystem[s]. > That way you can properly > handle the user/kernel documentation and persistance over time (i.e. you > can't change it.) On the other, hand properly designed fs-based interface requires less modification of userspeace to use it. Acctually, you can use most of fs-based intefaces directly from shell. No need in libc modifications and utilities to use it from shell or other script language. See cgroup, for example. > So yes, a syscall would be better, especially as this does not exactly > fit into the model of sysfs, right? Yes, sysfs is not the best place for it, but... -- Kirill A. Shutemov -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/