From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Aneesh Kumar K.V" Subject: Re: [PATCH mk-II 08/17] asm-generic/tlb: Provide MMU_GATHER_TABLE_FREE Date: Mon, 27 Jan 2020 13:43:34 +0530 Message-ID: <33932bc9-1fca-66ae-8f55-6da2f131c5be@linux.ibm.com> References: <20191211120713.360281197@infradead.org> <20191211122956.112607298@infradead.org> <20191212093205.GU2827@hirez.programming.kicks-ass.net> <20200126155205.GA19169@roeck-us.net> <20200127081134.GI14914@hirez.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:8908 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727754AbgA0INs (ORCPT ); Mon, 27 Jan 2020 03:13:48 -0500 Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 00R8AIAM103565 for ; Mon, 27 Jan 2020 03:13:46 -0500 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0b-001b2d01.pphosted.com with ESMTP id 2xrg61rffy-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 27 Jan 2020 03:13:46 -0500 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 27 Jan 2020 08:13:44 -0000 In-Reply-To: <20200127081134.GI14914@hirez.programming.kicks-ass.net> Content-Language: en-US Sender: linux-arch-owner@vger.kernel.org List-ID: To: Peter Zijlstra , Guenter Roeck Cc: Will Deacon , Andrew Morton , Nick Piggin , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Yoshinori Sato , Rich Felker , "David S. Miller" , Helge Deller , Geert Uytterhoeven , Paul Burton , Tony Luck , Richard Henderson , Nick Hu , Paul Walmsley On 1/27/20 1:41 PM, Peter Zijlstra wrote: > On Sun, Jan 26, 2020 at 07:52:05AM -0800, Guenter Roeck wrote: >> On Thu, Dec 12, 2019 at 10:32:05AM +0100, Peter Zijlstra wrote: >>> As described in the comment, the correct order for freeing pages is: >>> >>> 1) unhook page >>> 2) TLB invalidate page >>> 3) free page >>> >>> This order equally applies to page directories. >>> >>> Currently there are two correct options: >>> >>> - use tlb_remove_page(), when all page directores are full pages and >>> there are no futher contraints placed by things like software >>> walkers (HAVE_FAST_GUP). >>> >>> - use MMU_GATHER_RCU_TABLE_FREE and tlb_remove_table() when the >>> architecture does not do IPI based TLB invalidate and has >>> HAVE_FAST_GUP (or software TLB fill). >>> >>> This however leaves architectures that don't have page based >>> directories but don't need RCU in a bind. For those, provide >>> MMU_GATHER_TABLE_FREE, which provides the independent batching for >>> directories without the additional RCU freeing. >>> >>> Signed-off-by: Peter Zijlstra (Intel) >>> --- >> >> Various sparc64 builds (allnoconfig, tinyconfig, as well as builds >> with SMP disabled): >> >> mm/mmu_gather.c: In function '__tlb_remove_table_free': >> mm/mmu_gather.c:101:3: error: implicit declaration of function '__tlb_remove_table'; did you mean 'tlb_remove_table'? > > Thanks; I'll respin these patches against Aneesh' pile and make sure to > look into this when I do so. > > I did send a change to fix that. it is to drop !SMP change in the patch https://lore.kernel.org/linux-mm/87v9p9mhnr.fsf@linux.ibm.com -aneesh