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 2BE53C433DF for ; Mon, 1 Jun 2020 11:56:54 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E6CD520738 for ; Mon, 1 Jun 2020 11:56:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E6CD520738 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 72ADF80007; Mon, 1 Jun 2020 07:56:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6DC078E0006; Mon, 1 Jun 2020 07:56:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5F38480007; Mon, 1 Jun 2020 07:56:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0115.hostedemail.com [216.40.44.115]) by kanga.kvack.org (Postfix) with ESMTP id 494CC8E0006 for ; Mon, 1 Jun 2020 07:56:53 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 00FDE180AD806 for ; Mon, 1 Jun 2020 11:56:53 +0000 (UTC) X-FDA: 76880491506.30.cause85_591e2ac242334 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin30.hostedemail.com (Postfix) with ESMTP id DC2C3180B3C83 for ; Mon, 1 Jun 2020 11:56:52 +0000 (UTC) X-HE-Tag: cause85_591e2ac242334 X-Filterd-Recvd-Size: 4566 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf42.hostedemail.com (Postfix) with ESMTP for ; Mon, 1 Jun 2020 11:56:52 +0000 (UTC) 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 6BDFE55D; Mon, 1 Jun 2020 04:56:51 -0700 (PDT) Received: from gaia (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 291A23F52E; Mon, 1 Jun 2020 04:56:48 -0700 (PDT) Date: Mon, 1 Jun 2020 12:56:45 +0100 From: Catalin Marinas To: Zhenyu Ye Cc: peterz@infradead.org, mark.rutland@arm.com, will@kernel.org, aneesh.kumar@linux.ibm.com, akpm@linux-foundation.org, npiggin@gmail.com, arnd@arndb.de, rostedt@goodmis.org, maz@kernel.org, suzuki.poulose@arm.com, tglx@linutronix.de, yuzhao@google.com, Dave.Martin@arm.com, steven.price@arm.com, broonie@kernel.org, guohanjun@huawei.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, arm@kernel.org, xiexiangyou@huawei.com, prime.zeng@hisilicon.com, zhangshaokun@hisilicon.com, kuhn.chenqun@huawei.com Subject: Re: [PATCH v2 5/6] mm: tlb: Provide flush_*_tlb_range wrappers Message-ID: <20200601115644.GA23419@gaia> References: <20200423135656.2712-1-yezhenyu2@huawei.com> <20200423135656.2712-6-yezhenyu2@huawei.com> <20200522154254.GD26492@gaia> <20200526145244.GG17051@gaia> <0c6f79e4-f29a-d373-2e43-c4f87cf78b49@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0c6f79e4-f29a-d373-2e43-c4f87cf78b49@huawei.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Rspamd-Queue-Id: DC2C3180B3C83 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 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: Hi Zhenyu, On Sat, May 30, 2020 at 06:24:21PM +0800, Zhenyu Ye wrote: > On 2020/5/26 22:52, Catalin Marinas wrote: > > On Mon, May 25, 2020 at 03:19:42PM +0800, Zhenyu Ye wrote: > >> 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) > > > > Currently, flush_p??_tlb_range() are generic and defined as above. I > > think in the generic code they can remain an alias for > > flush_tlb_range(). > > > > On arm64, we can redefine them as: > > > > #define flush_pte_tlb_range(vma, addr, end) __flush_tlb_range(vma, addr, end, 3) > > #define flush_pmd_tlb_range(vma, addr, end) __flush_tlb_range(vma, addr, end, 2) > > #define flush_pud_tlb_range(vma, addr, end) __flush_tlb_range(vma, addr, end, 1) > > #define flush_p4d_tlb_range(vma, addr, end) __flush_tlb_range(vma, addr, end, 0) > > > > (unless the compiler optimises away all the mmu_gather stuff in your > > macro above but they don't look trivial to me) > > I changed generic code before considering that other structures may also > use this feature, such as Power9. And Peter may want to replace all > flush_tlb_range() by tlb_flush() in the future, see [1] for details. > > If only enable this feature on aarch64, your codes are better. > > [1] https://lore.kernel.org/linux-arm-kernel/20200402163849.GM20713@hirez.programming.kicks-ass.net/ But we change the semantics slightly if we implement these as mmu_gather. For example, tlb_end_vma() -> tlb_flush_mmu_tlbonly() ends up calling mmu_notifier_invalidate_range() which it didn't before. I think we end up invoking the notifier unnecessarily in some cases (see the comment in __split_huge_pmd()) or we end up calling the notifier twice (e.g. pmdp_huge_clear_flush_notify()). > > Also, I don't see the new flush_pte_* and flush_p4d_* macros used > > anywhere and I don't think they are needed. The pte equivalent is > > flush_tlb_page() (we need to make sure it's not used on a pmd in the > > hugetlb context). > > flush_tlb_page() is used to flush only one page. If we add the > flush_pte_tlb_range(), then we can use it to flush a range of pages in > the future. If we know flush_tlb_page() is only called on a small page, could we add TTL information here as well? > But flush_pte_* and flush_p4d_* macros are really not used anywhere. I > will remove them in next version of series, and add them if someone > needs. I think it makes sense. -- Catalin