From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx192.postini.com [74.125.245.192]) by kanga.kvack.org (Postfix) with SMTP id 86DCD6B0032 for ; Wed, 26 Jun 2013 00:03:35 -0400 (EDT) Received: by mail-pb0-f46.google.com with SMTP id rq2so13500563pbb.5 for ; Tue, 25 Jun 2013 21:03:34 -0700 (PDT) Date: Tue, 25 Jun 2013 21:03:31 -0700 From: Anton Vorontsov Subject: Re: [PATCH] vmpressure: implement strict mode Message-ID: <20130626040331.GA7993@teo> References: <20130625175129.7c0d79e1@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20130625175129.7c0d79e1@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Luiz Capitulino Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, mhocko@suse.cz, minchan@kernel.org, akpm@linux-foundation.org On Tue, Jun 25, 2013 at 05:51:29PM -0400, Luiz Capitulino wrote: > Currently, applications are notified for the level they registered for > _plus_ higher levels. > > This is a problem if the application wants to implement different > actions for different levels. For example, an application might want > to release 10% of its cache on level low, 50% on medium and 100% on > critical. To do this, the application has to register a different fd > for each event. However, fd low is always going to be notified and > and all fds are going to be notified on level critical. > > Strict mode solves this problem by strictly notifiying the event > an fd has registered for. It's optional. By default we still notify > on higher levels. > > Signed-off-by: Luiz Capitulino In the documentation I would add more information about why exactly the strict mode makes sense. For example, the non-strict fd listener hooked onto the low level makes sense for apps that just monitor reclaiming activity (like current Android Activity Manager), hooking onto 'medium' non-strict mode makes sense for simple load-balancing logic, and the new strict mode is for the cases when an application wants to implement some fancy logic as it makes a decision based on a concrete level. Otherwise, it looks good. Acked-by: Anton Vorontsov Thanks! Anton -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751246Ab3FZEDg (ORCPT ); Wed, 26 Jun 2013 00:03:36 -0400 Received: from mail-pa0-f54.google.com ([209.85.220.54]:65268 "EHLO mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750712Ab3FZEDf (ORCPT ); Wed, 26 Jun 2013 00:03:35 -0400 Date: Tue, 25 Jun 2013 21:03:31 -0700 From: Anton Vorontsov To: Luiz Capitulino Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, mhocko@suse.cz, minchan@kernel.org, akpm@linux-foundation.org Subject: Re: [PATCH] vmpressure: implement strict mode Message-ID: <20130626040331.GA7993@teo> References: <20130625175129.7c0d79e1@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20130625175129.7c0d79e1@redhat.com> 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 Tue, Jun 25, 2013 at 05:51:29PM -0400, Luiz Capitulino wrote: > Currently, applications are notified for the level they registered for > _plus_ higher levels. > > This is a problem if the application wants to implement different > actions for different levels. For example, an application might want > to release 10% of its cache on level low, 50% on medium and 100% on > critical. To do this, the application has to register a different fd > for each event. However, fd low is always going to be notified and > and all fds are going to be notified on level critical. > > Strict mode solves this problem by strictly notifiying the event > an fd has registered for. It's optional. By default we still notify > on higher levels. > > Signed-off-by: Luiz Capitulino In the documentation I would add more information about why exactly the strict mode makes sense. For example, the non-strict fd listener hooked onto the low level makes sense for apps that just monitor reclaiming activity (like current Android Activity Manager), hooking onto 'medium' non-strict mode makes sense for simple load-balancing logic, and the new strict mode is for the cases when an application wants to implement some fancy logic as it makes a decision based on a concrete level. Otherwise, it looks good. Acked-by: Anton Vorontsov Thanks! Anton