From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 75A8FDDE01 for ; Sat, 19 Jul 2008 08:06:16 +1000 (EST) Subject: Re: [PATCH][RT][PPC64] Fix preempt unsafe paths accessing per_cpu variables From: Benjamin Herrenschmidt To: Chirag Jog In-Reply-To: <20080718101133.GO20277@linux.vnet.ibm.com> References: <20080709160543.GG7101@linux.vnet.ibm.com> <1216085521.7740.37.camel@pasglop> <20080717125645.GN20277@linux.vnet.ibm.com> <1216325671.7740.359.camel@pasglop> <20080718101133.GO20277@linux.vnet.ibm.com> Content-Type: text/plain; charset=utf-8 Date: Sat, 19 Jul 2008 08:05:30 +1000 Message-Id: <1216418730.7740.451.camel@pasglop> Mime-Version: 1.0 Cc: linux-rt-users@vger.kernel.org, Josh Triplett , Steven Rostedt , linuxppc-dev@ozlabs.org, Nivedita Singhvi , "Timothy R. Chavez" , Thomas Gleixner , paulmck@linux.vnet.ibm.com, linux.kernel@vger.kernel.org Reply-To: benh@kernel.crashing.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > With the original patch, the pending batch does get flushed > in a non-preemptable region. > I am resending the original with just adding the necesary comments. Your comment isn't what I meant. What I meant is that if the process is context switched while walking the page tables, the low level powerpc context switch code should also perform a __flush_tlb_pending. BTW. Is the pte_lock also not a real spinlock anymore ? That may break other assumptions the powerpc mm code is doing. This -rt stuff is just too scary, it changes some fundamental semantics of the spinlocks. yuck. Ben. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCH][RT][PPC64] Fix preempt unsafe paths accessing per_cpu variables Date: Sat, 19 Jul 2008 08:05:30 +1000 Message-ID: <1216418730.7740.451.camel@pasglop> References: <20080709160543.GG7101@linux.vnet.ibm.com> <1216085521.7740.37.camel@pasglop> <20080717125645.GN20277@linux.vnet.ibm.com> <1216325671.7740.359.camel@pasglop> <20080718101133.GO20277@linux.vnet.ibm.com> Reply-To: benh@kernel.crashing.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux.kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, linuxppc-dev@ozlabs.org, Josh Triplett , Steven Rostedt , Nivedita Singhvi , "Timothy R. Chavez" , paulmck@linux.vnet.ibm.com, Thomas Gleixner To: Chirag Jog Return-path: Received: from gate.crashing.org ([63.228.1.57]:41418 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754124AbYGRWGS (ORCPT ); Fri, 18 Jul 2008 18:06:18 -0400 In-Reply-To: <20080718101133.GO20277@linux.vnet.ibm.com> Sender: linux-rt-users-owner@vger.kernel.org List-ID: > With the original patch, the pending batch does get flushed=20 > in a non-preemptable region.=20 > I am resending the original with just adding the necesary comments. Your comment isn't what I meant. What I meant is that if the process is context switched while walking the page tables, the low level powerp= c context switch code should also perform a =EF=BB=BF__flush_tlb_pending. BTW. Is the pte_lock also not a real spinlock anymore ? That may break other assumptions the powerpc mm code is doing. This -rt stuff is just too scary, it changes some fundamental semantics of the spinlocks. yuck. Ben. -- To unsubscribe from this list: send the line "unsubscribe linux-rt-user= s" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html