From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754024AbaCGRTO (ORCPT ); Fri, 7 Mar 2014 12:19:14 -0500 Received: from www.sr71.net ([198.145.64.142]:48893 "EHLO blackbird.sr71.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751676AbaCGRTN (ORCPT ); Fri, 7 Mar 2014 12:19:13 -0500 Message-ID: <5319FF8D.1080107@sr71.net> Date: Fri, 07 Mar 2014 09:19:09 -0800 From: Dave Hansen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: Davidlohr Bueso CC: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, ak@linux.intel.com, kirill.shutemov@linux.intel.com, mgorman@suse.de, alex.shi@linaro.org, x86@kernel.org, linux-mm@kvack.org, dave.hansen@linux.intel.com Subject: Re: [PATCH 5/7] x86: mm: new tunable for single vs full TLB flush References: <20140306004519.BBD70A1A@viggo.jf.intel.com> <20140306004527.6C232C54@viggo.jf.intel.com> <1394156230.2555.19.camel@buesod1.americas.hpqcorp.net> In-Reply-To: <1394156230.2555.19.camel@buesod1.americas.hpqcorp.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/06/2014 05:37 PM, Davidlohr Bueso wrote: > On Wed, 2014-03-05 at 16:45 -0800, Dave Hansen wrote: >> From: Dave Hansen >> + >> +If you believe that invlpg is being called too often, you can >> +lower the tunable: >> + >> + /sys/debug/kernel/x86/tlb_single_page_flush_ceiling >> + > > Whenever this tunable needs to be updated, most users will not know what > a invlpg is and won't think in terms of pages either. How about making > this in units of Kb instead? But then again most of those users won't be > looking into tlb flushing issues anyways, so... Yeah, talking about the instruction directly in the documentation is probably going a bit far. I'll see if I can uplevel it a bit. It's obviously not a big deal to change it to be pages vs. kb, but for something that's as *COMPLETELY* developer-focused, I think we can keep it in pages. We don't want users fooling with this. > While obvious, tt should also mention that this does not apply to > hugepages. Good point.