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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 0460EC433DF for ; Thu, 4 Jun 2020 16:01:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C8A3F20772 for ; Thu, 4 Jun 2020 16:01:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="QuxCA5XG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729659AbgFDQBw (ORCPT ); Thu, 4 Jun 2020 12:01:52 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:27155 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729562AbgFDQBw (ORCPT ); Thu, 4 Jun 2020 12:01:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591286509; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=iWrRTcNC3vxAMhViJq+6IUc52AVbCSA6Csxp/to2MQo=; b=QuxCA5XGWLOpwYxAOibn0yV+qLb8+9LnvqgYt54f80EvWaiAZZNtAUNn8eM4OPYbT1Kj/D Z2sZ1WfCghZEtFMEpz/V2PidFRaUbDrdTXxuatKZJSpVmq2g6k4gLRIldT7WAjvOqCsCY7 2TAIauqC+oXneQ+uuge39qFVsFCvzHM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-242-cGn7IkydPU2FasNmC2N0-g-1; Thu, 04 Jun 2020 12:01:45 -0400 X-MC-Unique: cGn7IkydPU2FasNmC2N0-g-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 475C91005512; Thu, 4 Jun 2020 16:01:40 +0000 (UTC) Received: from [10.36.112.96] (ovpn-112-96.ams2.redhat.com [10.36.112.96]) by smtp.corp.redhat.com (Postfix) with ESMTP id AA78E5D9D3; Thu, 4 Jun 2020 16:01:29 +0000 (UTC) Subject: Re: [RFC v2 7/9] mm/damon: Implement callbacks for physical memory monitoring To: SeongJae Park Cc: akpm@linux-foundation.org, SeongJae Park , Jonathan.Cameron@Huawei.com, aarcange@redhat.com, acme@kernel.org, alexander.shishkin@linux.intel.com, amit@kernel.org, benh@kernel.crashing.org, brendan.d.gregg@gmail.com, brendanhiggins@google.com, cai@lca.pw, colin.king@canonical.com, corbet@lwn.net, dwmw@amazon.com, foersleo@amazon.de, irogers@google.com, jolsa@redhat.com, kirill@shutemov.name, mark.rutland@arm.com, mgorman@suse.de, minchan@kernel.org, mingo@redhat.com, namhyung@kernel.org, peterz@infradead.org, rdunlap@infradead.org, riel@surriel.com, rientjes@google.com, rostedt@goodmis.org, sblbir@amazon.com, shakeelb@google.com, shuah@kernel.org, sj38.park@gmail.com, snu@amazon.de, vbabka@suse.cz, vdavydov.dev@gmail.com, yang.shi@linux.alibaba.com, ying.huang@intel.com, linux-damon@amazon.com, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org References: <20200604155158.12760-1-sjpark@amazon.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= mQINBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABtCREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT6JAlgEEwEIAEICGwMFCQlmAYAGCwkIBwMCBhUI AgkKCwQWAgMBAh4BAheAFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl3pImkCGQEACgkQTd4Q 9wD/g1o+VA//SFvIHUAvul05u6wKv/pIR6aICPdpF9EIgEU448g+7FfDgQwcEny1pbEzAmiw zAXIQ9H0NZh96lcq+yDLtONnXk/bEYWHHUA014A1wqcYNRY8RvY1+eVHb0uu0KYQoXkzvu+s Dncuguk470XPnscL27hs8PgOP6QjG4jt75K2LfZ0eAqTOUCZTJxA8A7E9+XTYuU0hs7QVrWJ jQdFxQbRMrYz7uP8KmTK9/Cnvqehgl4EzyRaZppshruKMeyheBgvgJd5On1wWq4ZUV5PFM4x II3QbD3EJfWbaJMR55jI9dMFa+vK7MFz3rhWOkEx/QR959lfdRSTXdxs8V3zDvChcmRVGN8U Vo93d1YNtWnA9w6oCW1dnDZ4kgQZZSBIjp6iHcA08apzh7DPi08jL7M9UQByeYGr8KuR4i6e RZI6xhlZerUScVzn35ONwOC91VdYiQgjemiVLq1WDDZ3B7DIzUZ4RQTOaIWdtXBWb8zWakt/ ztGhsx0e39Gvt3391O1PgcA7ilhvqrBPemJrlb9xSPPRbaNAW39P8ws/UJnzSJqnHMVxbRZC Am4add/SM+OCP0w3xYss1jy9T+XdZa0lhUvJfLy7tNcjVG/sxkBXOaSC24MFPuwnoC9WvCVQ ZBxouph3kqc4Dt5X1EeXVLeba+466P1fe1rC8MbcwDkoUo65Ag0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAGJAiUEGAECAA8FAlXLn5ECGwwFCQlmAYAACgkQTd4Q 9wD/g1qA6w/+M+ggFv+JdVsz5+ZIc6MSyGUozASX+bmIuPeIecc9UsFRatc91LuJCKMkD9Uv GOcWSeFpLrSGRQ1Z7EMzFVU//qVs6uzhsNk0RYMyS0B6oloW3FpyQ+zOVylFWQCzoyyf227y GW8HnXunJSC+4PtlL2AY4yZjAVAPLK2l6mhgClVXTQ/S7cBoTQKP+jvVJOoYkpnFxWE9pn4t H5QIFk7Ip8TKr5k3fXVWk4lnUi9MTF/5L/mWqdyIO1s7cjharQCstfWCzWrVeVctpVoDfJWp 4LwTuQ5yEM2KcPeElLg5fR7WB2zH97oI6/Ko2DlovmfQqXh9xWozQt0iGy5tWzh6I0JrlcxJ ileZWLccC4XKD1037Hy2FLAjzfoWgwBLA6ULu0exOOdIa58H4PsXtkFPrUF980EEibUp0zFz GotRVekFAceUaRvAj7dh76cToeZkfsjAvBVb4COXuhgX6N4pofgNkW2AtgYu1nUsPAo+NftU CxrhjHtLn4QEBpkbErnXQyMjHpIatlYGutVMS91XTQXYydCh5crMPs7hYVsvnmGHIaB9ZMfB njnuI31KBiLUks+paRkHQlFcgS2N3gkRBzH7xSZ+t7Re3jvXdXEzKBbQ+dC3lpJB0wPnyMcX FOTT3aZT7IgePkt5iC/BKBk3hqKteTnJFeVIT7EC+a6YUFg= Organization: Red Hat GmbH Message-ID: Date: Thu, 4 Jun 2020 18:01:28 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200604155158.12760-1-sjpark@amazon.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04.06.20 17:51, SeongJae Park wrote: > On Thu, 4 Jun 2020 17:39:49 +0200 David Hildenbrand wrote: > >> On 04.06.20 17:23, SeongJae Park wrote: >>> On Thu, 4 Jun 2020 16:58:13 +0200 David Hildenbrand wrote: >>> >>>> On 04.06.20 09:26, SeongJae Park wrote: >>>>> On Wed, 3 Jun 2020 18:09:21 +0200 David Hildenbrand wrote: >>>>> >>>>>> On 03.06.20 16:11, SeongJae Park wrote: >>>>>>> From: SeongJae Park >>>>>>> >>>>>>> This commit implements the four callbacks (->init_target_regions, >>>>>>> ->update_target_regions, ->prepare_access_check, and ->check_accesses) >>>>>>> for the basic access monitoring of the physical memory address space. >>>>>>> By setting the callback pointers to point those, users can easily >>>>>>> monitor the accesses to the physical memory. >>>>>>> >>>>>>> Internally, it uses the PTE Accessed bit, as similar to that of the >>>>>>> virtual memory support. Also, it supports only page frames that >>>>>>> supported by idle page tracking. Acutally, most of the code is stollen >>>>>>> from idle page tracking. Users who want to use other access check >>>>>>> primitives and monitor the frames that not supported with this >>>>>>> implementation could implement their own callbacks on their own. >>>>>>> >>>>>>> Signed-off-by: SeongJae Park >>>>>>> --- >>>>>>> include/linux/damon.h | 5 ++ >>>>>>> mm/damon.c | 184 ++++++++++++++++++++++++++++++++++++++++++ >>>>>>> 2 files changed, 189 insertions(+) >>>>>>> >>>>>>> diff --git a/include/linux/damon.h b/include/linux/damon.h >>>>>>> index 1a788bfd1b4e..f96503a532ea 100644 >>>>>>> --- a/include/linux/damon.h >>>>>>> +++ b/include/linux/damon.h >>>>>>> @@ -216,6 +216,11 @@ void kdamond_update_vm_regions(struct damon_ctx *ctx); >>>>>>> void kdamond_prepare_vm_access_checks(struct damon_ctx *ctx); >>>>>>> unsigned int kdamond_check_vm_accesses(struct damon_ctx *ctx); >>>>>>> >>>>>>> +void kdamond_init_phys_regions(struct damon_ctx *ctx); >>>>>>> +void kdamond_update_phys_regions(struct damon_ctx *ctx); >>>>>>> +void kdamond_prepare_phys_access_checks(struct damon_ctx *ctx); >>>>>>> +unsigned int kdamond_check_phys_accesses(struct damon_ctx *ctx); >>>>>>> + >>>>>>> int damon_set_pids(struct damon_ctx *ctx, int *pids, ssize_t nr_pids); >>>>>>> int damon_set_attrs(struct damon_ctx *ctx, unsigned long sample_int, >>>>>>> unsigned long aggr_int, unsigned long regions_update_int, >>>>>>> diff --git a/mm/damon.c b/mm/damon.c >>>>>>> index f5cbc97a3bbc..6a5c6d540580 100644 >>>>>>> --- a/mm/damon.c >>>>>>> +++ b/mm/damon.c >>>>>>> @@ -19,7 +19,9 @@ >>>>>>> #include >>>>>>> #include >>>>>>> #include >>>>>>> +#include >>>>>>> #include >>>>>>> +#include >>>>>>> #include >>>>>>> #include >>>>>>> #include >>>>>>> @@ -480,6 +482,11 @@ void kdamond_init_vm_regions(struct damon_ctx *ctx) >>>>>>> } >>>>>>> } >>>>>>> >>>>>>> +/* Do nothing. Users should set the initial regions by themselves */ >>>>>>> +void kdamond_init_phys_regions(struct damon_ctx *ctx) >>>>>>> +{ >>>>>>> +} >>>>>>> + >>>>>>> static void damon_mkold(struct mm_struct *mm, unsigned long addr) >>>>>>> { >>>>>>> pte_t *pte = NULL; >>>>>>> @@ -611,6 +618,178 @@ unsigned int kdamond_check_vm_accesses(struct damon_ctx *ctx) >>>>>>> return max_nr_accesses; >>>>>>> } >>>>>>> >>>>>>> +/* access check functions for physical address based regions */ >>>>>>> + >>>>>>> +/* This code is stollen from page_idle.c */ >>>>>>> +static struct page *damon_phys_get_page(unsigned long pfn) >>>>>>> +{ >>>>>>> + struct page *page; >>>>>>> + pg_data_t *pgdat; >>>>>>> + >>>>>>> + if (!pfn_valid(pfn)) >>>>>>> + return NULL; >>>>>>> + >>>>>> >>>>>> Who provides these pfns? Can these be random pfns, supplied unchecked by >>>>>> user space? Or are they at least mapped into some user space process? >>>>> >>>>> Your guess is right, users can give random physical address and that will be >>>>> translated into pfn. >>>>> >>>> >>>> Note the difference to idle tracking: "Idle page tracking only considers >>>> user memory pages", this is very different to your use case. Note that >>>> this is why there is no pfn_to_online_page() check in page idle code. >>> >>> My use case is same to that of idle page. I also ignore non-user pages. >>> Actually, this function is for filtering of the non-user pages, which is simply >>> stollen from the page_idle. >> >> Okay, that is valuable information, I missed that. The comment in >> page_idle.c is actually pretty valuable. >> >> In both cases, user space can provide random physical address but you >> will only care about user pages. Understood. >> >> That turns things less dangerous. :) > > Glad to hear this. I will refine this point in the next spin! :) Perfect, when I read "physical address space", I was assuming you would magically track access to e.g., memmap, page tables and stuff like that. And I wondered how you would do that :D BTW now that I realized that as we only care about LRU pages, page_to_online_page() is sufficient, no need to worry about dax/pmem. -- Thanks, David / dhildenb