Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753668AbaJ1MNE (ORCPT ); Tue, 28 Oct 2014 08:13:04 -0400 Received: from mga09.intel.com ([134.134.136.24]:47493 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751700AbaJ1MNC (ORCPT ); Tue, 28 Oct 2014 08:13:02 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,802,1406617200"; d="scan'208";a="597602675" From: Andi Kleen To: Alex Thorlton Cc: linux-mm@kvack.org, Andrew Morton , Bob Liu , David Rientjes , "Eric W. Biederman" , Hugh Dickins , Ingo Molnar , Kees Cook , "Kirill A. Shutemov" , Mel Gorman , Oleg Nesterov , Peter Zijlstra , Rik van Riel , Thomas Gleixner , Vladimir Davydov , linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/4] Convert khugepaged to a task_work function References: <1414032567-109765-1-git-send-email-athorlton@sgi.com> Date: Tue, 28 Oct 2014 05:12:26 -0700 In-Reply-To: <1414032567-109765-1-git-send-email-athorlton@sgi.com> (Alex Thorlton's message of "Wed, 22 Oct 2014 21:49:23 -0500") Message-ID: <87lho0pf4l.fsf@tassilo.jf.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Alex Thorlton writes: > Last week, while discussing possible fixes for some unexpected/unwanted behavior > from khugepaged (see: https://lkml.org/lkml/2014/10/8/515) several people > mentioned possibly changing changing khugepaged to work as a task_work function > instead of a kernel thread. This will give us finer grained control over the > page collapse scans, eliminate some unnecessary scans since tasks that are > relatively inactive will not be scanned often, and eliminate the unwanted > behavior described in the email thread I mentioned. With your change, what would happen in a single threaded case? Previously one core would scan and another would run the workload. With your change both scanning and running would be on the same core. Would seem like a step backwards to me. -Andi -- ak@linux.intel.com -- Speaking for myself only -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/