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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 94CEEC6FA8A for ; Fri, 9 Sep 2022 04:26:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229604AbiIIE0f (ORCPT ); Fri, 9 Sep 2022 00:26:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35162 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229577AbiIIE0e (ORCPT ); Fri, 9 Sep 2022 00:26:34 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 7F31B49B76; Thu, 8 Sep 2022 21:26:33 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 7C014153B; Thu, 8 Sep 2022 21:26:39 -0700 (PDT) Received: from [10.162.41.8] (unknown [10.162.41.8]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3D5263F71A; Thu, 8 Sep 2022 21:26:23 -0700 (PDT) Message-ID: Date: Fri, 9 Sep 2022 09:56:21 +0530 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH v3 1/4] Revert "Documentation/features: mark BATCHED_UNMAP_TLB_FLUSH doesn't apply to ARM64" Content-Language: en-US To: Yicong Yang , akpm@linux-foundation.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, x86@kernel.org, catalin.marinas@arm.com, will@kernel.org, linux-doc@vger.kernel.org Cc: corbet@lwn.net, peterz@infradead.org, arnd@arndb.de, linux-kernel@vger.kernel.org, darren@os.amperecomputing.com, yangyicong@hisilicon.com, huzhanyuan@oppo.com, lipeifeng@oppo.com, zhangshiming@oppo.com, guojian@oppo.com, realmz6@gmail.com, linux-mips@vger.kernel.org, openrisc@lists.librecores.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, Barry Song <21cnbao@gmail.com>, wangkefeng.wang@huawei.com, xhao@linux.alibaba.com, prime.zeng@hisilicon.com, Barry Song References: <20220822082120.8347-1-yangyicong@huawei.com> <20220822082120.8347-2-yangyicong@huawei.com> From: Anshuman Khandual In-Reply-To: <20220822082120.8347-2-yangyicong@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 8/22/22 13:51, Yicong Yang wrote: > From: Barry Song > > This reverts commit 6bfef171d0d74cb050112e0e49feb20bfddf7f42. > > I was wrong. Though ARM64 has hardware TLB flush, but it is not free > and it is still expensive. > We still have a good chance to enable batched and deferred TLB flush > on ARM64 for memory reclamation. A possible way is that we only queue > tlbi instructions in hardware's queue. When we have to broadcast TLB, > we broadcast it by dsb. We just need to get adapted the existing > BATCHED_UNMAP_TLB_FLUSH. > > Tested-by: Xin Hao > Signed-off-by: Barry Song > Signed-off-by: Yicong Yang > --- > Documentation/features/arch-support.txt | 1 - > Documentation/features/vm/TLB/arch-support.txt | 2 +- > 2 files changed, 1 insertion(+), 2 deletions(-) > > diff --git a/Documentation/features/arch-support.txt b/Documentation/features/arch-support.txt > index 118ae031840b..d22a1095e661 100644 > --- a/Documentation/features/arch-support.txt > +++ b/Documentation/features/arch-support.txt > @@ -8,5 +8,4 @@ The meaning of entries in the tables is: > | ok | # feature supported by the architecture > |TODO| # feature not yet supported by the architecture > | .. | # feature cannot be supported by the hardware > - | N/A| # feature doesn't apply to the architecture > > diff --git a/Documentation/features/vm/TLB/arch-support.txt b/Documentation/features/vm/TLB/arch-support.txt > index 039e4e91ada3..1c009312b9c1 100644 > --- a/Documentation/features/vm/TLB/arch-support.txt > +++ b/Documentation/features/vm/TLB/arch-support.txt > @@ -9,7 +9,7 @@ > | alpha: | TODO | > | arc: | TODO | > | arm: | TODO | > - | arm64: | N/A | > + | arm64: | TODO | > | csky: | TODO | > | hexagon: | TODO | > | ia64: | TODO | I believe this patch is not needed, which explicitly reverts an older commit. Instead when ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH framework gets enabled on arm64, the same patch could just drop 'NA' as possible values for arch support for a give feature in file Documentation/features/arch-support.txt.