From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8657C73C5C for ; Tue, 9 Jul 2019 21:17:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A83DB20844 for ; Tue, 9 Jul 2019 21:17:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727656AbfGIVRi (ORCPT ); Tue, 9 Jul 2019 17:17:38 -0400 Received: from mx0a-002e3701.pphosted.com ([148.163.147.86]:12432 "EHLO mx0a-002e3701.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726462AbfGIVRi (ORCPT ); Tue, 9 Jul 2019 17:17:38 -0400 Received: from pps.filterd (m0134421.ppops.net [127.0.0.1]) by mx0b-002e3701.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x69LGFNl024628; Tue, 9 Jul 2019 21:17:21 GMT Received: from g9t5009.houston.hpe.com (g9t5009.houston.hpe.com [15.241.48.73]) by mx0b-002e3701.pphosted.com with ESMTP id 2tmye9987t-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 09 Jul 2019 21:17:21 +0000 Received: from g4t3433.houston.hpecorp.net (g4t3433.houston.hpecorp.net [16.208.49.245]) by g9t5009.houston.hpe.com (Postfix) with ESMTP id DE5AE58; Tue, 9 Jul 2019 21:17:20 +0000 (UTC) Received: from [16.116.129.61] (unknown [16.116.129.61]) by g4t3433.houston.hpecorp.net (Postfix) with ESMTP id C1B7248; Tue, 9 Jul 2019 21:17:18 +0000 (UTC) Subject: Re: [PATCH v2 8/9] x86/mm/tlb: Remove UV special case To: Nadav Amit Cc: Russ Anderson , Thomas Gleixner , Andy Lutomirski , Dave Hansen , "x86@kernel.org" , LKML , Peter Zijlstra , Ingo Molnar , Dave Hansen , Dimitri Sivanich , Hedi Berriche References: <20190702235151.4377-1-namit@vmware.com> <20190702235151.4377-9-namit@vmware.com> <20190709200914.fjvi3cy3qfc6fmis@hpe.com> <373adfb0-0047-eae2-46a5-041caddfca97@hpe.com> <3AA5020A-111F-48F4-A0E9-B3C09E5EC43E@vmware.com> From: Mike Travis Message-ID: <6a40267d-f646-5406-db14-155ecd05cf48@hpe.com> Date: Tue, 9 Jul 2019 14:17:18 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.1 MIME-Version: 1.0 In-Reply-To: <3AA5020A-111F-48F4-A0E9-B3C09E5EC43E@vmware.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-HPE-SCL: -1 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-07-09_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1907090256 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/9/2019 2:09 PM, Nadav Amit wrote: >> On Jul 9, 2019, at 1:29 PM, Mike Travis wrote: >> >> >> >> On 7/9/2019 1:09 PM, Russ Anderson wrote: >>> On Tue, Jul 09, 2019 at 09:50:27PM +0200, Thomas Gleixner wrote: >>>> On Tue, 2 Jul 2019, Nadav Amit wrote: >>>> >>>>> SGI UV support is outdated and not maintained, and it is not clear how >>>>> it performs relatively to non-UV. Remove the code to simplify the code. >>>> >>>> You should at least Cc the SGI/HP folks on that. They are still >>>> around. Done so. >>> Thanks Thomas. The SGI UV is now HPE Superdome Flex and is >>> very much still supported. >>> Thanks. >>>>> Cc: Peter Zijlstra >>>>> Cc: Dave Hansen >>>>> Suggested-by: Andy Lutomirski >>>>> Signed-off-by: Nadav Amit >>>>> --- >>>>> arch/x86/mm/tlb.c | 25 ------------------------- >>>>> 1 file changed, 25 deletions(-) >>>>> >>>>> diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c >>>>> index b47a71820f35..64afe1215495 100644 >>>>> --- a/arch/x86/mm/tlb.c >>>>> +++ b/arch/x86/mm/tlb.c >>>>> @@ -689,31 +689,6 @@ void native_flush_tlb_multi(const struct cpumask *cpumask, >>>>> trace_tlb_flush(TLB_REMOTE_SEND_IPI, >>>>> (info->end - info->start) >> PAGE_SHIFT); >>>>> - if (is_uv_system()) { >>>>> - /* >>>>> - * This whole special case is confused. UV has a "Broadcast >>>>> - * Assist Unit", which seems to be a fancy way to send IPIs. >>>>> - * Back when x86 used an explicit TLB flush IPI, UV was >>>>> - * optimized to use its own mechanism. These days, x86 uses >>>>> - * smp_call_function_many(), but UV still uses a manual IPI, >>>>> - * and that IPI's action is out of date -- it does a manual >>>>> - * flush instead of calling flush_tlb_func_remote(). This >>>>> - * means that the percpu tlb_gen variables won't be updated >>>>> - * and we'll do pointless flushes on future context switches. >>>>> - * >>>>> - * Rather than hooking native_flush_tlb_multi() here, I think >>>>> - * that UV should be updated so that smp_call_function_many(), >>>>> - * etc, are optimal on UV. >>>>> - */ >> >> I thought this change was already proposed a bit ago and we acked it >> awhile back. Also the replacement functionality is being worked on but it >> is more complex. The smp call many has to support all the reasons why it’s >> called and not just the tlb shoot downs as is the current BAU case. > > Sorry for not cc’ing you before. In the meanwhile, can you give an explicit > acked-by? (I couldn’t find the previous patch you regarded.) Sure: Acked-by: Mike Travis > > Thanks, > Nadav >