From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758750Ab2FHHdV (ORCPT ); Fri, 8 Jun 2012 03:33:21 -0400 Received: from mail-qc0-f174.google.com ([209.85.216.174]:52053 "EHLO mail-qc0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752081Ab2FHHdT (ORCPT ); Fri, 8 Jun 2012 03:33:19 -0400 Message-ID: <4FD1AABD.7010602@gmail.com> Date: Fri, 08 Jun 2012 03:33:17 -0400 From: KOSAKI Motohiro User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: leonid.moiseichuk@nokia.com CC: kosaki.motohiro@gmail.com, anton.vorontsov@linaro.org, penberg@kernel.org, b.zolnierkie@samsung.com, john.stultz@linaro.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org, patches@linaro.org, kernel-team@android.com Subject: Re: [PATCH 2/5] vmevent: Convert from deferred timer to deferred work References: <20120601122118.GA6128@lizard> <1338553446-22292-2-git-send-email-anton.vorontsov@linaro.org> <4FD170AA.10705@gmail.com> <20120608065828.GA1515@lizard> <84FF21A720B0874AA94B46D76DB98269045F7890@008-AM1MPN1-004.mgdnok.nokia.com> <84FF21A720B0874AA94B46D76DB98269045F78E1@008-AM1MPN1-004.mgdnok.nokia.com> <84FF21A720B0874AA94B46D76DB98269045F7918@008-AM1MPN1-004.mgdnok.nokia.com> In-Reply-To: <84FF21A720B0874AA94B46D76DB98269045F7918@008-AM1MPN1-004.mgdnok.nokia.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (6/8/12 3:28 AM), leonid.moiseichuk@nokia.com wrote: >> -----Original Message----- >> From: ext KOSAKI Motohiro [mailto:kosaki.motohiro@gmail.com] >> Sent: 08 June, 2012 10:23 > ... >>> If you wakeup only by signal when memory situation changed you can be >> not mlocked. >>> Mlocking uses memory very inefficient way and usually cannot be applied >> for apps which wants to be notified due to resources restrictions. >> >> That's your choice. If you don't need to care cache dropping, We don't >> enforce it. I only pointed out your explanation was technically incorrect. > > My explanation is correct. That is an overhead you have to pay if start to >use API based on polling from user-space and this overhead narrows API >applicability. > Moving all times/tracking to kernel avoid useless wakeups in user-space. Wrong. CPU don't realized the running code belong to userspace or kernel. Every code just consume a power. That's why polling timer is wrong from point of power consumption view.