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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 C0C6AC433DF for ; Mon, 1 Jun 2020 14:57:57 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 88BD6207DF for ; Mon, 1 Jun 2020 14:57:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 88BD6207DF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1DDF080007; Mon, 1 Jun 2020 10:57:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 18F838E0006; Mon, 1 Jun 2020 10:57:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0CD9E80007; Mon, 1 Jun 2020 10:57:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0101.hostedemail.com [216.40.44.101]) by kanga.kvack.org (Postfix) with ESMTP id E7BE58E0006 for ; Mon, 1 Jun 2020 10:57:56 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id A9E35824805A for ; Mon, 1 Jun 2020 14:57:56 +0000 (UTC) X-FDA: 76880947752.08.death55_454374a6f6253 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin08.hostedemail.com (Postfix) with ESMTP id 89FD9180703B4 for ; Mon, 1 Jun 2020 14:57:56 +0000 (UTC) X-HE-Tag: death55_454374a6f6253 X-Filterd-Recvd-Size: 2611 Received: from huawei.com (szxga05-in.huawei.com [45.249.212.191]) by imf05.hostedemail.com (Postfix) with ESMTP for ; Mon, 1 Jun 2020 14:57:55 +0000 (UTC) Received: from DGGEMS410-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 1D32A44F0A1957BAB3EB; Mon, 1 Jun 2020 22:57:46 +0800 (CST) Received: from [127.0.0.1] (10.173.220.25) by DGGEMS410-HUB.china.huawei.com (10.3.19.210) with Microsoft SMTP Server id 14.3.487.0; Mon, 1 Jun 2020 22:57:36 +0800 Subject: Re: [RFC PATCH v3 2/2] arm64: tlb: Use the TLBI RANGE feature in arm64 To: Catalin Marinas CC: , , , , , , , , , , , , , , References: <20200414112835.1121-1-yezhenyu2@huawei.com> <20200414112835.1121-3-yezhenyu2@huawei.com> <20200514152840.GC1907@gaia> <54468aae-dbb1-66bd-c633-82fc75936206@huawei.com> <20200520170759.GE18302@gaia> From: Zhenyu Ye Message-ID: Date: Mon, 1 Jun 2020 22:57:35 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: <20200520170759.GE18302@gaia> Content-Type: text/plain; charset="gbk" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.173.220.25] X-CFilter-Loop: Reflected X-Rspamd-Queue-Id: 89FD9180703B4 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000028, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi Catalin, I have sent the v4 of this series [1] and combine the two function with a single loop. See codes for details. [1] https://lore.kernel.org/linux-arm-kernel/20200601144713.2222-1-yezhenyu2@huawei.com/ On 2020/5/21 1:08, Catalin Marinas wrote: >> This optimization is only effective when the range is a multiple of 256KB >> (when the page size is 4KB), and I'm worried about the performance >> of ilog2(). I traced the __flush_tlb_range() last year and found that in >> most cases the range is less than 256K (see details in [1]). > > THP or hugetlbfs would exercise bigger strides but I guess it depends on > the use-case. ilog2() should be reduced to a few instructions on arm64 > AFAICT (haven't tried but it should use the CLZ instruction). > Not bigger than 256K, but the range must be a integer multiple of 256KB, so I still start from scale 0. Thanks, Zhenyu