From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f53.google.com (mail-pa0-f53.google.com [209.85.220.53]) by kanga.kvack.org (Postfix) with ESMTP id D88D56B0036 for ; Fri, 7 Mar 2014 12:19:14 -0500 (EST) Received: by mail-pa0-f53.google.com with SMTP id ld10so4418459pab.12 for ; Fri, 07 Mar 2014 09:19:14 -0800 (PST) Received: from blackbird.sr71.net (www.sr71.net. [198.145.64.142]) by mx.google.com with ESMTP id n8si8919424pab.290.2014.03.07.09.19.13 for ; Fri, 07 Mar 2014 09:19:13 -0800 (PST) Message-ID: <5319FF8D.1080107@sr71.net> Date: Fri, 07 Mar 2014 09:19:09 -0800 From: Dave Hansen MIME-Version: 1.0 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: owner-linux-mm@kvack.org List-ID: 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 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. -- 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