From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754518Ab3F1A65 (ORCPT ); Thu, 27 Jun 2013 20:58:57 -0400 Received: from mail-pd0-f172.google.com ([209.85.192.172]:57682 "EHLO mail-pd0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754219Ab3F1A64 (ORCPT ); Thu, 27 Jun 2013 20:58:56 -0400 Date: Thu, 27 Jun 2013 17:58:53 -0700 From: Anton Vorontsov To: Andrew Morton Cc: Minchan Kim , Luiz Capitulino , linux-mm@kvack.org, linux-kernel@vger.kernel.org, mhocko@suse.cz, kmpark@infradead.org, hyunhee.kim@samsung.com Subject: Re: [PATCH v2] vmpressure: implement strict mode Message-ID: <20130628005852.GA8093@teo> References: <20130626231712.4a7392a7@redhat.com> <20130627150231.2bc00e3efcd426c4beef894c@linux-foundation.org> <20130628000201.GB15637@bbox> <20130627173433.d0fc6ecd.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20130627173433.d0fc6ecd.akpm@linux-foundation.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 27, 2013 at 05:34:33PM -0700, Andrew Morton wrote: > > If so, userland daemon would receive lots of events which are no interest. > > "lots"? If vmpressure is generating events at such a high frequency that > this matters then it's already busted? Current frequency is 1/(2MB). Suppose we ended up scanning the whole memory on a 2GB host, this will give us 1024 hits. Doesn't feel too much* to me... But for what it worth, I am against adding read() to the interface -- just because we can avoid the unnecessary switch into the kernel. * For bigger hosts we should increase the window, as we do for the vmstat.