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=-9.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 A033DC433E0 for ; Wed, 27 Jan 2021 16:57:31 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 21D6A64DA0 for ; Wed, 27 Jan 2021 16:57:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 21D6A64DA0 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=amazon.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 358E36B0006; Wed, 27 Jan 2021 11:57:30 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2E10B6B006E; Wed, 27 Jan 2021 11:57:30 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 184E66B0070; Wed, 27 Jan 2021 11:57:30 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0169.hostedemail.com [216.40.44.169]) by kanga.kvack.org (Postfix) with ESMTP id EAB5F6B0006 for ; Wed, 27 Jan 2021 11:57:29 -0500 (EST) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id A8E8B180AD822 for ; Wed, 27 Jan 2021 16:57:29 +0000 (UTC) X-FDA: 77752161018.12.cover03_4b03a9027598 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin12.hostedemail.com (Postfix) with ESMTP id 570671801D7E5 for ; Wed, 27 Jan 2021 16:57:16 +0000 (UTC) X-HE-Tag: cover03_4b03a9027598 X-Filterd-Recvd-Size: 6643 Received: from smtp-fw-9101.amazon.com (smtp-fw-9101.amazon.com [207.171.184.25]) by imf49.hostedemail.com (Postfix) with ESMTP for ; Wed, 27 Jan 2021 16:57:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1611766636; x=1643302636; h=from:to:cc:subject:date:message-id:in-reply-to: mime-version; bh=i5zluJQ8Ep7MHqr2mjA7/P86f9akCWCX+vhcFXDo1AU=; b=vAenk/67rMLQ+7qYNgEungkfLcc+jSvfUqk0o85m6MRhhkRlDIFJZDRE HjFUA0C90WuDLjc7HfMRF6AudB9brRRrLZoEOMv5OfzCMH7+3asqlnkTv MEujAoERNix212DHA0PBCilIsMyrKOyU/VmH3aUle56ZHhO9fK0e0jfEc g=; X-IronPort-AV: E=Sophos;i="5.79,380,1602547200"; d="scan'208";a="106835424" Received: from sea3-co-svc-lb6-vlan2.sea.amazon.com (HELO email-inbound-relay-2b-8cc5d68b.us-west-2.amazon.com) ([10.47.22.34]) by smtp-border-fw-out-9101.sea19.amazon.com with ESMTP; 27 Jan 2021 16:57:08 +0000 Received: from EX13D31EUA001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan3.pdx.amazon.com [10.236.137.198]) by email-inbound-relay-2b-8cc5d68b.us-west-2.amazon.com (Postfix) with ESMTPS id 6986AA18C3; Wed, 27 Jan 2021 16:57:05 +0000 (UTC) Received: from u3f2cd687b01c55.ant.amazon.com (10.43.160.132) by EX13D31EUA001.ant.amazon.com (10.43.165.15) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 27 Jan 2021 16:56:48 +0000 From: SeongJae Park To: SeongJae Park CC: Shakeel Butt , , "Andrea Arcangeli" , , , , , , Brendan Higgins , Qian Cai , Colin Ian King , Jonathan Corbet , "David Hildenbrand" , , Marco Elver , "Du, Fan" , , "Greg Thelen" , Ian Rogers , , "Kirill A. Shutemov" , Mark Rutland , Mel Gorman , Minchan Kim , Ingo Molnar , , "Peter Zijlstra (Intel)" , Randy Dunlap , Rik van Riel , David Rientjes , Steven Rostedt , Mike Rapoport , , Shuah Khan , , , Vlastimil Babka , Vladimir Davydov , Yang Shi , Huang Ying , , , Linux MM , , LKML Subject: Re: [PATCH v23 05/15] mm/damon: Implement primitives for the virtual memory address spaces Date: Wed, 27 Jan 2021 17:56:30 +0100 Message-ID: <20210127165630.29904-1-sjpark@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201224071111.11551-1-sjpark@amazon.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.43.160.132] X-ClientProxiedBy: EX13D28UWC004.ant.amazon.com (10.43.162.24) To EX13D31EUA001.ant.amazon.com (10.43.165.15) 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 Thu, 24 Dec 2020 08:11:11 +0100 SeongJae Park wrote: > On Wed, 23 Dec 2020 14:54:02 -0800 Shakeel Butt wrote: > > > On Wed, Dec 23, 2020 at 8:47 AM SeongJae Park wrote: > > > > > [snip] > > > > [snip] > > > > > + > > > > > +static bool damon_va_young(struct mm_struct *mm, unsigned long addr, > > > > > + unsigned long *page_sz) > > > > > +{ > > > > > + pte_t *pte = NULL; > > > > > + pmd_t *pmd = NULL; > > > > > + spinlock_t *ptl; > > > > > + bool young = false; > > > > > + > > > > > + if (follow_pte_pmd(mm, addr, NULL, &pte, &pmd, &ptl)) > > > > > + return false; > > > > > + > > > > > + *page_sz = PAGE_SIZE; > > > > > + if (pte) { > > > > > + young = pte_young(*pte); > > > > > + if (!young) > > > > > + young = !page_is_idle(pte_page(*pte)); > > > > > + pte_unmap_unlock(pte, ptl); > > > > > + return young; > > > > > + } > > > > > + > > > > > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > > > > > + young = pmd_young(*pmd); > > > > > + if (!young) > > > > > + young = !page_is_idle(pmd_page(*pmd)); > > > > > + spin_unlock(ptl); > > > > > + *page_sz = ((1UL) << HPAGE_PMD_SHIFT); > > > > > +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ > > > > > + > > > > > + return young; > > > > > > > > You need mmu_notifier_test_young() here. Hmm I remember mentioning > > > > this in some previous version as well. > > > > > > Your question and my answer was as below: > > > > > > > Don't you need mmu_notifier_clear_young() here? > > > > > > I think we don't need it here because we only read the Accessed bit and PG_Idle > > > if Accessed bit was not set. > > > > > > I should notice that you mean 'test_young()' but didn't, sorry. I will add it > > > in the next version. > > > > > > > I should have said mmu_notifier_test_young() instead of > > mmu_notifier_clear_young(). > > > > > > > > > > BTW have you tested this on a VM? > > > > > > Yes. Indeed, I'm testing this on a QEMU/KVM environment. You can get more > > > detail at: https://damonitor.github.io/doc/html/latest/vm/damon/eval.html#setup > > > > > > > Hmm without mmu_notifier_test_young() you should be missing the kvm > > mmu access updates. Can you please recheck if your eval is correctly > > seeing the memory accesses from the VM? > > Seems I didn't clearly answered, sorry. My test setup installs the > DAMON-enabled kernel in a guest VM and run it for workloads in the guest, > rather than running DAMON in host to monitor accesses of VMs. The MMU notifier > is for latter case, AFAIU, so my test setup didn't see the problem. Just FYI. I confirmed the mmu_notifier_test_young() added version works for the use case. I tested it by running a program accessing 200MB memory in a QEMU/KVM guest having 120GB memory and monitoring the qemu process' virtual address space from the host using DAMON. The 200MB memory region was clearly identifiable. Thanks, SeongJae Park