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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 BD3FBC433DF for ; Mon, 25 May 2020 07:19:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 64F61207DA for ; Mon, 25 May 2020 07:19:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 64F61207DA 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 BF6BE8001E; Mon, 25 May 2020 03:19:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B80AF8000E; Mon, 25 May 2020 03:19:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A6F578001E; Mon, 25 May 2020 03:19:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0165.hostedemail.com [216.40.44.165]) by kanga.kvack.org (Postfix) with ESMTP id 8C6E28000E for ; Mon, 25 May 2020 03:19:58 -0400 (EDT) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 3C03E1EFF for ; Mon, 25 May 2020 07:19:58 +0000 (UTC) X-FDA: 76854392076.04.spot20_1cbcb98897f51 X-HE-Tag: spot20_1cbcb98897f51 X-Filterd-Recvd-Size: 3783 Received: from huawei.com (szxga07-in.huawei.com [45.249.212.35]) by imf18.hostedemail.com (Postfix) with ESMTP for ; Mon, 25 May 2020 07:19:57 +0000 (UTC) Received: from DGGEMS402-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 9EC1B2FB3E70016EC513; Mon, 25 May 2020 15:19:52 +0800 (CST) Received: from [127.0.0.1] (10.173.220.25) by DGGEMS402-HUB.china.huawei.com (10.3.19.202) with Microsoft SMTP Server id 14.3.487.0; Mon, 25 May 2020 15:19:44 +0800 Subject: Re: [PATCH v2 5/6] mm: tlb: Provide flush_*_tlb_range wrappers To: Catalin Marinas CC: , , , , , , , , , , , , , , , , , , , , , , , , References: <20200423135656.2712-1-yezhenyu2@huawei.com> <20200423135656.2712-6-yezhenyu2@huawei.com> <20200522154254.GD26492@gaia> From: Zhenyu Ye Message-ID: Date: Mon, 25 May 2020 15:19:42 +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: <20200522154254.GD26492@gaia> Content-Type: text/plain; charset="gbk" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.173.220.25] X-CFilter-Loop: Reflected X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2020/5/22 23:42, Catalin Marinas wrote: > On Thu, Apr 23, 2020 at 09:56:55PM +0800, Zhenyu Ye wrote: >> diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c >> index 3d7c01e76efc..3eff199d3507 100644 >> --- a/mm/pgtable-generic.c >> +++ b/mm/pgtable-generic.c >> @@ -101,6 +101,28 @@ pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address, >> >> #ifdef CONFIG_TRANSPARENT_HUGEPAGE >> >> +#ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE >> + >> +#define FLUSH_Pxx_TLB_RANGE(_pxx) \ >> +void flush_##_pxx##_tlb_range(struct vm_area_struct *vma, \ >> + unsigned long addr, unsigned long end) \ >> +{ \ >> + struct mmu_gather tlb; \ >> + \ >> + tlb_gather_mmu(&tlb, vma->vm_mm, addr, end); \ >> + tlb_start_vma(&tlb, vma); \ >> + tlb_flush_##_pxx##_range(&tlb, addr, end - addr); \ >> + tlb_end_vma(&tlb, vma); \ >> + tlb_finish_mmu(&tlb, addr, end); \ >> +} > > I may have confused myself (flush_p??_tlb_* vs. tlb_flush_p??_*) but do > actually need this whole tlb_gather thing here? IIUC (by grep'ing), > flush_p?d_tlb_range() is only called on huge pages, so we should know > the level already. > tlb_flush_##_pxx##_range() is used to set tlb->cleared_*, flush_##_pxx##_tlb_range() will actually flush the TLB entry. In arch64, tlb_flush_p?d_range() is defined as: #define flush_pmd_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end) #define flush_pud_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end) So even if we know the level here, we can not pass the value to tlbi instructions (flush_tlb_range() is a common kernel interface and retro-fit it needs lots of changes), according to Peter's suggestion, I finally decide to pass the value of TTL by the tlb_gather_* frame.[1] [1] https://lore.kernel.org/linux-arm-kernel/20200331142927.1237-1-yezhenyu2@huawei.com/ Thanks, Zhenyu