From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755500AbdAIWEI (ORCPT ); Mon, 9 Jan 2017 17:04:08 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:52453 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750981AbdAIWEF (ORCPT ); Mon, 9 Jan 2017 17:04:05 -0500 Date: Mon, 9 Jan 2017 23:03:59 +0100 (CET) From: Thomas Gleixner To: Fenghua Yu cc: Shaohua Li , LKML , Peter Zijlstra Subject: Re: [PATCH] x86/intel_rdt: reinitialize cbm for new group allocation In-Reply-To: <20170109215558.GA7138@linux.intel.com> Message-ID: References: <91a513378542f2d81e39baf954d8f8c447fd1943.1483747472.git.shli@fb.com> <20170109215558.GA7138@linux.intel.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 9 Jan 2017, Fenghua Yu wrote: > On Fri, Jan 06, 2017 at 04:05:19PM -0800, Shaohua Li wrote: > But since you come here now, I would think reseting the CBM in > closid_free() is better. No. closid_free() is the wrong place. closid_alloc/free() merily deal with the bitmap and nothing else. If you really want to do that, then this needs a seperate function called from rmdir. > The reason is user can see "right" max_cbm even through rdmsr after > rmdir, ie no gap for cbm values between rmdir and the next mkdir. And the value pf this is? The closid is not usable after the rmdir, so it's really completely uninteresting when the user can read the old value from that configuration MSR. When the closid is reused then it hardly matters either what's in those cbm values (the old or max_cbm). Thanks, tglx