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=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 65825C433E5 for ; Fri, 17 Jul 2020 08:32:15 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 21D7A2071A for ; Fri, 17 Jul 2020 08:32:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="IRgF6Nyu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 21D7A2071A 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 A8AAA8D0019; Fri, 17 Jul 2020 04:32:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A39598D0001; Fri, 17 Jul 2020 04:32:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 929378D0019; Fri, 17 Jul 2020 04:32:14 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0190.hostedemail.com [216.40.44.190]) by kanga.kvack.org (Postfix) with ESMTP id 7945C8D0001 for ; Fri, 17 Jul 2020 04:32:14 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 353618248047 for ; Fri, 17 Jul 2020 08:32:14 +0000 (UTC) X-FDA: 77046900588.21.bee62_4d00a5626f09 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin21.hostedemail.com (Postfix) with ESMTP id D5C6E181F0FEA for ; Fri, 17 Jul 2020 08:31:33 +0000 (UTC) X-HE-Tag: bee62_4d00a5626f09 X-Filterd-Recvd-Size: 7682 Received: from smtp-fw-9102.amazon.com (smtp-fw-9102.amazon.com [207.171.184.29]) by imf15.hostedemail.com (Postfix) with ESMTP for ; Fri, 17 Jul 2020 08:31:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1594974693; x=1626510693; h=from:to:cc:subject:date:message-id:in-reply-to: mime-version; bh=UbdGYUcxs3f2PzsC5b1THW/4XAQ8PtwmIHoCMkMyeJk=; b=IRgF6NyuvORaBmk2nw1T36eeh2txS4IQ3TNHR4e2DFSO+uAxWMpKTDTV l/wFslprUJKuJrGsr408dXPOCDOLsb1VtSqPNi/CKZMnZCjJVs2KpmcwM BlJjGylvaO9d1+AEZ8JqIKktsVHZXTA/qAODdbP3pYFDi4j3OUchs8NP4 I=; IronPort-SDR: jTvzNbc6LpWJ1wdVACIj01E7k7YcB0jnHfAPb0ZjxcDFQlY+r7xF67ZzlciV069UlBFd+uFpyb pV3oC7mKs+AQ== X-IronPort-AV: E=Sophos;i="5.75,362,1589241600"; d="scan'208";a="60527465" Received: from sea32-co-svc-lb4-vlan3.sea.corp.amazon.com (HELO email-inbound-relay-2b-a7fdc47a.us-west-2.amazon.com) ([10.47.23.38]) by smtp-border-fw-out-9102.sea19.amazon.com with ESMTP; 17 Jul 2020 06:53:51 +0000 Received: from EX13MTAUEA002.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan2.pdx.amazon.com [10.170.41.162]) by email-inbound-relay-2b-a7fdc47a.us-west-2.amazon.com (Postfix) with ESMTPS id 7C722C1B5E; Fri, 17 Jul 2020 06:53:48 +0000 (UTC) Received: from EX13D31EUA004.ant.amazon.com (10.43.165.161) by EX13MTAUEA002.ant.amazon.com (10.43.61.77) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 17 Jul 2020 06:53:47 +0000 Received: from u886c93fd17d25d.ant.amazon.com (10.43.161.34) by EX13D31EUA004.ant.amazon.com (10.43.165.161) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 17 Jul 2020 06:53:30 +0000 From: SeongJae Park To: Shakeel Butt CC: SeongJae Park , Andrew Morton , SeongJae Park , , Andrea Arcangeli , , , , , , Brendan Higgins , Qian Cai , Colin Ian King , Jonathan Corbet , "David Hildenbrand" , , , Ian Rogers , , "Kirill A. Shutemov" , , Mel Gorman , Minchan Kim , Ingo Molnar , , "Peter Zijlstra (Intel)" , Randy Dunlap , Rik van Riel , David Rientjes , Steven Rostedt , , , , , , Vlastimil Babka , Vladimir Davydov , Yang Shi , Huang Ying , , Linux MM , , LKML Subject: Re: Re: [PATCH v18 06/14] mm/damon: Implement callbacks for the virtual memory address spaces Date: Fri, 17 Jul 2020 08:53:13 +0200 Message-ID: <20200717065313.8870-1-sjpark@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: (raw) MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.43.161.34] X-ClientProxiedBy: EX13D37UWA001.ant.amazon.com (10.43.160.61) To EX13D31EUA004.ant.amazon.com (10.43.165.161) X-Rspamd-Queue-Id: D5C6E181F0FEA X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 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, 16 Jul 2020 17:46:54 -0700 Shakeel Butt wrote: > On Mon, Jul 13, 2020 at 1:44 AM SeongJae Park wrote: > > > > From: SeongJae Park > > > > This commit introduces a reference implementation of the address space > > specific low level primitives for the virtual address space, so that > > users of DAMON can easily monitor the data accesses on virtual address > > spaces of specific processes by simply configuring the implementation to > > be used by DAMON. > > > > The low level primitives for the fundamental access monitoring are > > defined in two parts: > > 1. Identification of the monitoring target address range for the address > > space. > > 2. Access check of specific address range in the target space. > > > > The reference implementation for the virtual address space provided by > > this commit is designed as below. > > > > PTE Accessed-bit Based Access Check > > ----------------------------------- > > > > The implementation uses PTE Accessed-bit for basic access checks. That > > is, it clears the bit for next sampling target page and checks whether > > it set again after one sampling period. To avoid disturbing other > > Accessed bit users such as the reclamation logic, the implementation > > adjusts the ``PG_Idle`` and ``PG_Young`` appropriately, as same to the > > 'Idle Page Tracking'. > > > > VMA-based Target Address Range Construction > > ------------------------------------------- > > > > Only small parts in the super-huge virtual address space of the > > processes are mapped to physical memory and accessed. Thus, tracking > > the unmapped address regions is just wasteful. However, because DAMON > > can deal with some level of noise using the adaptive regions adjustment > > mechanism, tracking every mapping is not strictly required but could > > even incur a high overhead in some cases. That said, too huge unmapped > > areas inside the monitoring target should be removed to not take the > > time for the adaptive mechanism. > > > > For the reason, this implementation converts the complex mappings to > > three distinct regions that cover every mapped area of the address > > space. Also, the two gaps between the three regions are the two biggest > > unmapped areas in the given address space. The two biggest unmapped > > areas would be the gap between the heap and the uppermost mmap()-ed > > region, and the gap between the lowermost mmap()-ed region and the stack > > in most of the cases. Because these gaps are exceptionally huge in > > usual address spacees, excluding these will be sufficient to make a > > reasonable trade-off. Below shows this in detail:: > > > > > > > > > > (small mmap()-ed regions and munmap()-ed regions) > > > > > > > > > > Signed-off-by: SeongJae Park > > Reviewed-by: Leonard Foerster > [snip] > > + > > +static void damon_mkold(struct mm_struct *mm, unsigned long addr) > > +{ > > + pte_t *pte = NULL; > > + pmd_t *pmd = NULL; > > + spinlock_t *ptl; > > + > > + if (follow_pte_pmd(mm, addr, NULL, &pte, &pmd, &ptl)) > > + return; > > + > > + if (pte) { > > + if (pte_young(*pte)) { > > Any reason for skipping mmu_notifier_clear_young()? Why exclude VMs as > DAMON's target applications? Obviously my mistake, thank you for pointing this! I will add the function call in the next spin. Thanks, SeongJae Park > > > + clear_page_idle(pte_page(*pte)); > > + set_page_young(pte_page(*pte)); > > + } > > + *pte = pte_mkold(*pte); > > + pte_unmap_unlock(pte, ptl); > > + return; > > + } > > +