From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx167.postini.com [74.125.245.167]) by kanga.kvack.org (Postfix) with SMTP id C62C06B004D for ; Wed, 25 Jan 2012 03:20:05 -0500 (EST) From: Subject: RE: [RFC 1/3] /dev/low_mem_notify Date: Wed, 25 Jan 2012 08:19:11 +0000 Message-ID: <84FF21A720B0874AA94B46D76DB9826904562B60@008-AM1MPN1-003.mgdnok.nokia.com> References: <84FF21A720B0874AA94B46D76DB98269045596EA@008-AM1MPN1-003.mgdnok.nokia.com> <84FF21A720B0874AA94B46D76DB982690455978C@008-AM1MPN1-003.mgdnok.nokia.com> <4F175706.8000808@redhat.com> <4F17DCED.4020908@redhat.com> <4F17E058.8020008@redhat.com> <84FF21A720B0874AA94B46D76DB9826904559D46@008-AM1MPN1-003.mgdnok.nokia.com> <20120124153835.GA10990@amt.cnet> <1327421440.13624.30.camel@jaguar> In-Reply-To: <1327421440.13624.30.camel@jaguar> Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: penberg@kernel.org, mtosatti@redhat.com Cc: rhod@redhat.com, riel@redhat.com, minchan@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kamezawa.hiroyu@jp.fujitsu.com, mel@csn.ul.ie, rientjes@google.com, kosaki.motohiro@gmail.com, hannes@cmpxchg.org, akpm@linux-foundation.org, kosaki.motohiro@jp.fujitsu.com > -----Original Message----- > From: ext Pekka Enberg [mailto:penberg@kernel.org] > Sent: 24 January, 2012 18:11 > To: Marcelo Tosatti .... > On Tue, 2012-01-24 at 13:38 -0200, Marcelo Tosatti wrote: > > Having userspace specify the "sample period" for low memory > > notification makes no sense. The frequency of notifications is a > > function of the memory pressure. >=20 > Sure, it makes sense to autotune sample period. I don't see the problem > with letting userspace decide it for themselves if they want to. >=20 > Pekka Good point, but you must take into account that reaction time in user-space= depends how SW stack is organized. So for some components 1s is good enough update time, for another cases 10= ms. If changes on VM happened too often they had no sense for user-space. Thus from practical point of view having sampling period is not a bad idea. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org