From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-f170.google.com (mail-ie0-f170.google.com [209.85.223.170]) by kanga.kvack.org (Postfix) with ESMTP id 818286B0032 for ; Thu, 23 Apr 2015 14:52:46 -0400 (EDT) Received: by iedfl3 with SMTP id fl3so76311185ied.1 for ; Thu, 23 Apr 2015 11:52:46 -0700 (PDT) Received: from e37.co.us.ibm.com (e37.co.us.ibm.com. [32.97.110.158]) by mx.google.com with ESMTPS id c18si48987igr.39.2015.04.23.11.52.45 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 23 Apr 2015 11:52:45 -0700 (PDT) Received: from /spool/local by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 23 Apr 2015 12:52:45 -0600 Received: from b03cxnp08028.gho.boulder.ibm.com (b03cxnp08028.gho.boulder.ibm.com [9.17.130.20]) by d03dlp03.boulder.ibm.com (Postfix) with ESMTP id 8FA3F19D8048 for ; Thu, 23 Apr 2015 12:43:46 -0600 (MDT) Received: from d03av05.boulder.ibm.com (d03av05.boulder.ibm.com [9.17.195.85]) by b03cxnp08028.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t3NIqNXs40894712 for ; Thu, 23 Apr 2015 11:52:23 -0700 Received: from d03av05.boulder.ibm.com (localhost [127.0.0.1]) by d03av05.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t3NIqeKs017145 for ; Thu, 23 Apr 2015 12:52:41 -0600 Date: Thu, 23 Apr 2015 11:52:40 -0700 From: "Paul E. McKenney" Subject: Re: Interacting with coherent memory on external devices Message-ID: <20150423185240.GO5561@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20150421214445.GA29093@linux.vnet.ibm.com> <1429663372.27410.75.camel@kernel.crashing.org> <20150422005757.GP5561@linux.vnet.ibm.com> <1429664686.27410.84.camel@kernel.crashing.org> <20150422163135.GA4062@gmail.com> <1429756456.4915.22.camel@kernel.crashing.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Benjamin Herrenschmidt , Jerome Glisse , linux-kernel@vger.kernel.org, linux-mm@kvack.org, jglisse@redhat.com, mgorman@suse.de, aarcange@redhat.com, riel@redhat.com, airlied@redhat.com, aneesh.kumar@linux.vnet.ibm.com, Cameron Buschardt , Mark Hairgrove , Geoffrey Gerfin , John McKenna , akpm@linux-foundation.org On Thu, Apr 23, 2015 at 09:38:15AM -0500, Christoph Lameter wrote: > On Thu, 23 Apr 2015, Benjamin Herrenschmidt wrote: [ . . . ] > > It might not be *your* model based on *your* application but that doesn't mean > > it's not there, and isn't relevant. > > Sadly this is the way that an entire industry does its thing. I must confess that I got lost in the pronouns. If by "this is the way" and "entire industry" you mean hand-tuning for the former and the specific industry you are in for the latter, I am with you. And again, we are not going to do anything that would prevent hand-tuning. For example, it will be possible to completely disable any migration operations that might contribute to OS jitter. And I have added a requirement that this migration mechanism not contribute to OS jitter unless it is enabled. Does that help? If by "entire industry" you mean everyone who might want to use hardware acceleration, for example, including mechanical computer-aided design, I am skeptical. Thanx, Paul -- 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