Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752178AbbKYSDx (ORCPT ); Wed, 25 Nov 2015 13:03:53 -0500 Received: from mail-wm0-f46.google.com ([74.125.82.46]:34822 "EHLO mail-wm0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751180AbbKYSDx (ORCPT ); Wed, 25 Nov 2015 13:03:53 -0500 Date: Wed, 25 Nov 2015 19:03:50 +0100 From: Michal Hocko To: Christoph Lameter Cc: Joonsoo Kim , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm/vmstat: retrieve more accurate vmstat value Message-ID: <20151125180350.GT27283@dhcp22.suse.cz> References: <1448346123-2699-1-git-send-email-iamjoonsoo.kim@lge.com> <20151125025735.GC9563@js1304-P5Q-DELUXE> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 957 Lines: 23 On Wed 25-11-15 10:04:44, Christoph Lameter wrote: > On Wed, 25 Nov 2015, Joonsoo Kim wrote: > > > I think that maintaining duplicate counter to guarantee accuracy isn't > > reasonable solution. It would cause more overhead to the system. > > Simply remove the counter from the vmstat handling and do it differently > then. We definitely do not want yet another set of counters. vmstat counters are not only to be exported into the userspace. We have in kernel users as well. I do agree that there are users who can cope with some level of imprecision though and those which depend on the accuracy can use zone_page_state_snapshot which doesn't impose any overhead on others. [...] -- Michal Hocko SUSE Labs -- 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/