From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f49.google.com (mail-wm0-f49.google.com [74.125.82.49]) by kanga.kvack.org (Postfix) with ESMTP id 4901E6B0255 for ; Wed, 25 Nov 2015 13:03:53 -0500 (EST) Received: by wmww144 with SMTP id w144so190608644wmw.1 for ; Wed, 25 Nov 2015 10:03:52 -0800 (PST) Received: from mail-wm0-f44.google.com (mail-wm0-f44.google.com. [74.125.82.44]) by mx.google.com with ESMTPS id t132si7387777wmt.17.2015.11.25.10.03.52 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 25 Nov 2015 10:03:52 -0800 (PST) Received: by wmuu63 with SMTP id u63so148463160wmu.0 for ; Wed, 25 Nov 2015 10:03:52 -0800 (PST) Date: Wed, 25 Nov 2015 19:03:50 +0100 From: Michal Hocko 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: Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Joonsoo Kim , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org