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=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 86538C282DD for ; Fri, 10 Jan 2020 14:35:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 48E702077C for ; Fri, 10 Jan 2020 14:35:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="EM6EbFdn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 48E702077C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id CE6738E0006; Fri, 10 Jan 2020 09:34:59 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C97718E0001; Fri, 10 Jan 2020 09:34:59 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B868C8E0006; Fri, 10 Jan 2020 09:34:59 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0105.hostedemail.com [216.40.44.105]) by kanga.kvack.org (Postfix) with ESMTP id A28388E0001 for ; Fri, 10 Jan 2020 09:34:59 -0500 (EST) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 54F184850 for ; Fri, 10 Jan 2020 14:34:59 +0000 (UTC) X-FDA: 76361971518.30.worm39_82bd53b9af046 X-HE-Tag: worm39_82bd53b9af046 X-Filterd-Recvd-Size: 9728 Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) by imf32.hostedemail.com (Postfix) with ESMTP for ; Fri, 10 Jan 2020 14:34:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1578666897; 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=qe/DQSO6egNN12VNLBtfG0e8j23Y5iaWIY6p3G6nAtQ=; b=EM6EbFdnf0vlOTVNZ7MNljTPSig8cWaLIXL/nI9fvvz0rFX6MsaNlz47OvIzfM+3kkf5dX ZGGAa+SkWAdzHyI+cUaliQ0z7EJos09ldlWE31UH95FB59PVifaUZapU/8sWah1AHQ/imj wBEBrtQkrxRbXVZbyrgAz4B8o03TM1E= 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-110-cp5JE4GTN3K_w3Lg5T-CAw-1; Fri, 10 Jan 2020 09:34:54 -0500 X-MC-Unique: cp5JE4GTN3K_w3Lg5T-CAw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9063880058A; Fri, 10 Jan 2020 14:34:52 +0000 (UTC) Received: from [10.36.118.66] (unknown [10.36.118.66]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6ADAC7C82C; Fri, 10 Jan 2020 14:34:50 +0000 (UTC) Subject: Re: [PATCH] mm/page_alloc: Skip non present sections on zone initialization To: "Kirill A. Shutemov" Cc: Michal Hocko , Andrew Morton , Dan Williams , Vlastimil Babka , Mel Gorman , "Jin, Zhi" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" References: <20191230093828.24613-1-kirill.shutemov@linux.intel.com> <20200108144044.GB30379@dhcp22.suse.cz> <73437651-822f-fcec-3b96-281fb1064cf8@redhat.com> <20200110134547.v6ju5dxazknfjdj3@box> 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: Fri, 10 Jan 2020 15:34:49 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.1 MIME-Version: 1.0 In-Reply-To: <20200110134547.v6ju5dxazknfjdj3@box> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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 10.01.20 14:45, Kirill A. Shutemov wrote: > On Fri, Jan 10, 2020 at 02:15:26PM +0100, David Hildenbrand wrote: >> On 08.01.20 15:40, Michal Hocko wrote: >>> On Mon 30-12-19 12:38:28, Kirill A. Shutemov wrote: >>>> memmap_init_zone() can be called on the ranges with holes during the >>>> boot. It will skip any non-valid PFNs one-by-one. It works fine as long >>>> as holes are not too big. >>>> >>>> But huge holes in the memory map causes a problem. It takes over 20 >>>> seconds to walk 32TiB hole. x86-64 with 5-level paging allows for much >>>> larger holes in the memory map which would practically hang the system. >>>> >>>> Deferred struct page init doesn't help here. It only works on the >>>> present ranges. >>>> >>>> Skipping non-present sections would fix the issue. >>> >>> Makes sense to me. >>> >>>> Signed-off-by: Kirill A. Shutemov >>> >>> That pfn inc back and forth is quite ugly TBH but whatever. >> >> Indeed, can we please rewrite the loop to fix that? > > Any suggestions? > > I don't see an obvious way to not break readablity in another place. > I'd probably do it like this (applied some other tweaks, untested) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index cb766aac6772..a96b1ad1d74b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5859,6 +5859,22 @@ overlap_memmap_init(unsigned long zone, unsigned long *pfn) return false; } +static inline __meminit unsigned long next_present_pfn(unsigned long pfn) +{ +#ifdef CONFIG_SPARSEMEM + unsigned long section_nr = pfn_to_section_nr(pfn + 1); + + /* + * Note: We don't check the subsection bitmap, so this can produce + * false positives when only subsections are present/valid. The + * caller should recheck if the returned pfn is valid. + */ + if (!present_section_nr(section_nr)) + return section_nr_to_pfn(next_present_section_nr(section_nr)); +#endif + return pfn++; +} + /* * Initially all pages are reserved - free ones are freed * up by memblock_free_all() once the early boot process is @@ -5892,18 +5908,22 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, } #endif - for (pfn = start_pfn; pfn < end_pfn; pfn++) { + pfn = start_pfn; + while (pfn < end_pfn) { /* * There can be holes in boot-time mem_map[]s handed to this * function. They do not exist on hotplugged memory. */ if (context == MEMMAP_EARLY) { - if (!early_pfn_valid(pfn)) + if (!early_pfn_valid(pfn)) { + pfn = next_present_pfn(pfn, end_pfn); continue; - if (!early_pfn_in_nid(pfn, nid)) - continue; - if (overlap_memmap_init(zone, &pfn)) + } + if (!early_pfn_in_nid(pfn, nid) || + overlap_memmap_init(zone, &pfn)) { + pfn++; continue; + } if (defer_init(nid, pfn, end_pfn)) break; } @@ -5929,6 +5949,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, set_pageblock_migratetype(page, MIGRATE_MOVABLE); cond_resched(); } + pfn++; } I played with using a "pfn = next_init_pfn()" in the for loop instead, moving all the checks in there, but didn't turn out too well. -- Thanks, David / dhildenb