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=-15.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 8041FC433DB for ; Tue, 23 Feb 2021 06:11:10 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1DA5A64E4B for ; Tue, 23 Feb 2021 06:11:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1DA5A64E4B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=mpHV+53fMy/pjPUVQ0SpFa+bABkOjBey9ZuhojGyucA=; b=R9BB8aBzlwdt1HPQgpKmkPKrm IsF+p99s88MP0nVi4xp5qL/IlYme3OPRaeBSNA9LZYR6uzhqkbjvvD+upyl5G6C+ZIOlcorc0qQfh rTVjWkAwZYrE5x0QRiVQV9cuRMoEi0/HVLjAvpV2gspZjfXiq2CZDDdrXIBIJ0vrDX6x7Vx66no9e 6eE2PUlkFGESF6P5PVKNQoZS9espfiTfBxK948ieGVznHVLeuwnpVmXTqoD5B8ekFKEUTi/CexyWE 7nWr/GCpQOPiASWLYDltBxZgkPTLp/D0o1oV9a7x6T3Td36SegiOmgemorL8HyT4x2Dxo81sL12CC mkKZlr0Ew==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1lEQtT-00067C-EN; Tue, 23 Feb 2021 06:09:59 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1lEQtQ-00066E-HC for linux-arm-kernel@lists.infradead.org; Tue, 23 Feb 2021 06:09:57 +0000 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 409E7ED1; Mon, 22 Feb 2021 22:09:52 -0800 (PST) Received: from [192.168.0.130] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 368173F73D; Mon, 22 Feb 2021 22:09:47 -0800 (PST) Subject: Re: [PATCH] Documentation/features: mark BATCHED_UNMAP_TLB_FLUSH doesn't apply to ARM64 To: Barry Song , corbet@lwn.net, linux-doc@vger.kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org References: <20210223003230.11976-1-song.bao.hua@hisilicon.com> From: Anshuman Khandual Message-ID: <09dd1026-9e3f-b9be-b5a5-82771642348d@arm.com> Date: Tue, 23 Feb 2021 11:40:09 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210223003230.11976-1-song.bao.hua@hisilicon.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210223_010956_702272_D6489C7B X-CRM114-Status: GOOD ( 23.23 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Catalin Marinas , linux-kernel@vger.kernel.org, linuxarm@openeuler.org, Mel Gorman , Andy Lutomirski , Will Deacon , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2/23/21 6:02 AM, Barry Song wrote: > BATCHED_UNMAP_TLB_FLUSH is used on x86 to do batched tlb shootdown by > sending one IPI to TLB flush all entries after unmapping pages rather > than sending an IPI to flush each individual entry. > On arm64, tlb shootdown is done by hardware. Flush instructions are > innershareable. The local flushes are limited to the boot (1 per CPU) > and when a task is getting a new ASID. Is there any previous discussion around this ? > So marking this feature as "TODO" is not proper. ".." isn't good as > well. So this patch adds a "N/A" for this kind of features which are > not needed on some architectures. > > Cc: Mel Gorman > Cc: Andy Lutomirski > Cc: Catalin Marinas > Cc: Will Deacon > Signed-off-by: Barry Song > --- > Documentation/features/arch-support.txt | 1 + > Documentation/features/vm/TLB/arch-support.txt | 2 +- > 2 files changed, 2 insertions(+), 1 deletion(-) > > diff --git a/Documentation/features/arch-support.txt b/Documentation/features/arch-support.txt > index d22a1095e661..118ae031840b 100644 > --- a/Documentation/features/arch-support.txt > +++ b/Documentation/features/arch-support.txt > @@ -8,4 +8,5 @@ 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 NA might be better here. s/doesn't apply/not applicable/ in order to match NA. Still wondering if NA is really needed when there is already ".." ? Regardless either way should be fine. > > diff --git a/Documentation/features/vm/TLB/arch-support.txt b/Documentation/features/vm/TLB/arch-support.txt > index 30f75a79ce01..0d070f9f98d8 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: | TODO | > + | arm64: | N/A | > | c6x: | .. | > | csky: | TODO | > | h8300: | .. | > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel