From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stanislav Meduna Subject: Re: [PATCH] mm: fix up a spurious page fault whenever it happens Date: Thu, 20 Jun 2013 19:50:22 +0200 Message-ID: <51C340DE.30806@meduna.org> References: <519D118B.6010306@zytor.com> <519D11BF.5000604@redhat.com> <519DCE2A.4010801@meduna.org> <519E095A.4000105@redhat.com> <519F24DD.5060700@meduna.org> <519F65DB.2020305@redhat.com> <51BE2F5C.8070408@meduna.org> <51C0B177.2000006@meduna.org> <51C15F87.20100@meduna.org> <20130619080656.GF16094@twins.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Linus Torvalds , Rik van Riel , "H. Peter Anvin" , Steven Rostedt , "linux-rt-users@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Thomas Gleixner , Ingo Molnar , the arch/x86 maintainers , Hai Huang To: Peter Zijlstra Return-path: Received: from www.meduna.org ([92.240.244.38]:47955 "EHLO meduna.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758294Ab3FTRvK (ORCPT ); Thu, 20 Jun 2013 13:51:10 -0400 In-Reply-To: <20130619080656.GF16094@twins.programming.kicks-ass.net> Sender: linux-rt-users-owner@vger.kernel.org List-ID: On 19.06.2013 10:06, Peter Zijlstra wrote: >> On 19.06.2013 07:20, Linus Torvalds wrote: >>> There's the fast_tlb race that Peter fixed in commit 29eb77825cc7 >>> ("arch, mm: Remove tlb_fast_mode()"). I'm not seeing how it would >>> cause infinite TLB faults, but it definitely causes potentially >>> incoherent TLB contents. And afaik it only happens with >>> CONFIG_PREEMPT, and on UP systems. Which sounds like it might match >>> your setup... > The easiest way to test for your system is to ensure tlb_fast_mode() > return an unconditional 0. Nope. Got the faults also with tlb_fast_mode() returning 0, this time after ~10 hours. So there still has to be something... Regards -- Stano