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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 3C62EC4151A for ; Tue, 29 Jan 2019 10:04:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0A5D32177E for ; Tue, 29 Jan 2019 10:04:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727301AbfA2KD7 (ORCPT ); Tue, 29 Jan 2019 05:03:59 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55354 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725772AbfA2KD7 (ORCPT ); Tue, 29 Jan 2019 05:03:59 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5808CC7A07; Tue, 29 Jan 2019 10:03:58 +0000 (UTC) Received: from [10.36.118.12] (unknown [10.36.118.12]) by smtp.corp.redhat.com (Postfix) with ESMTP id EC295176AE; Tue, 29 Jan 2019 10:03:56 +0000 (UTC) Subject: Re: [PATCH] mm,memory_hotplug: Fix scan_movable_pages for gigantic hugepages To: Andrew Morton , Oscar Salvador , linux-mm@kvack.org, linux-kernel@vger.kernel.org, mhocko@suse.com References: <20190122154407.18417-1-osalvador@suse.de> <5368e2b4-5aca-40dd-fe18-67d861a04a29@redhat.com> <20190125075830.6mqw2io4rwz7wxx5@d104.suse.de> <20190128145309.c7dcf075b469d6a54694327d@linux-foundation.org> <20190128145617.069b3a5436fc7e34bdebb104@linux-foundation.org> From: David Hildenbrand Openpgp: preference=signencrypt Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= xsFNBFXLn5EBEAC+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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwX4EEwECACgFAljj9eoCGwMFCQlmAYAGCwkI BwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEE3eEPcA/4Na5IIP/3T/FIQMxIfNzZshIq687qgG 8UbspuE/YSUDdv7r5szYTK6KPTlqN8NAcSfheywbuYD9A4ZeSBWD3/NAVUdrCaRP2IvFyELj xoMvfJccbq45BxzgEspg/bVahNbyuBpLBVjVWwRtFCUEXkyazksSv8pdTMAs9IucChvFmmq3 jJ2vlaz9lYt/lxN246fIVceckPMiUveimngvXZw21VOAhfQ+/sofXF8JCFv2mFcBDoa7eYob s0FLpmqFaeNRHAlzMWgSsP80qx5nWWEvRLdKWi533N2vC/EyunN3HcBwVrXH4hxRBMco3jvM m8VKLKao9wKj82qSivUnkPIwsAGNPdFoPbgghCQiBjBe6A75Z2xHFrzo7t1jg7nQfIyNC7ez MZBJ59sqA9EDMEJPlLNIeJmqslXPjmMFnE7Mby/+335WJYDulsRybN+W5rLT5aMvhC6x6POK z55fMNKrMASCzBJum2Fwjf/VnuGRYkhKCqqZ8gJ3OvmR50tInDV2jZ1DQgc3i550T5JDpToh dPBxZocIhzg+MBSRDXcJmHOx/7nQm3iQ6iLuwmXsRC6f5FbFefk9EjuTKcLMvBsEx+2DEx0E UnmJ4hVg7u1PQ+2Oy+Lh/opK/BDiqlQ8Pz2jiXv5xkECvr/3Sv59hlOCZMOaiLTTjtOIU7Tq 7ut6OL64oAq+zsFNBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCghCj/CA/lc/LMthqQ773ga uB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseBfDXHA6m4B3mUTWo13nid 0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts6TZ+IrPOwT1hfB4WNC+X 2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiuQmt3yqrmN63V9wzaPhC+ xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKBTccu2AXJXWAE1Xjh6GOC 8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvFFFyAS0Nk1q/7EChPcbRb hJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh2YmnmLRTro6eZ/qYwWkC u8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRkF3TwgucpyPtcpmQtTkWS gDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0LLH63+BrrHasfJzxKXzqg rW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4vq7oFCPsOgwARAQABwsFl BBgBAgAPBQJVy5+RAhsMBQkJZgGAAAoJEE3eEPcA/4NagOsP/jPoIBb/iXVbM+fmSHOjEshl KMwEl/m5iLj3iHnHPVLBUWrXPdS7iQijJA/VLxjnFknhaS60hkUNWexDMxVVP/6lbOrs4bDZ NEWDMktAeqJaFtxackPszlcpRVkAs6Msn9tu8hlvB517pyUgvuD7ZS9gGOMmYwFQDyytpepo YApVV00P0u3AaE0Cj/o71STqGJKZxcVhPaZ+LR+UCBZOyKfEyq+ZN311VpOJZ1IvTExf+S/5 lqnciDtbO3I4Wq0ArLX1gs1q1XlXLaVaA3yVqeC8E7kOchDNinD3hJS4OX0e1gdsx/e6COvy qNg5aL5n0Kl4fcVqM0LdIhsubVs4eiNCa5XMSYpXmVi3HAuFyg9dN+x8thSwI836FoMASwOl C7tHsTjnSGufB+D7F7ZBT61BffNBBIm1KdMxcxqLUVXpBQHHlGkbwI+3Ye+nE6HmZH7IwLwV W+Ajl7oYF+jeKaH4DZFtgLYGLtZ1LDwKPjX7VAsa4Yx7S5+EBAaZGxK510MjIx6SGrZWBrrV TEvdV00F2MnQoeXKzD7O4WFbL55hhyGgfWTHwZ457iN9SgYi1JLPqWkZB0JRXIEtjd4JEQcx +8Umfre0Xt4713VxMygW0PnQt5aSQdMD58jHFxTk092mU+yIHj5LeYgvwSgZN4airXk5yRXl SE+xAvmumFBY Organization: Red Hat GmbH Message-ID: <33fdaa38-6204-bef0-b12f-0416f16dc165@redhat.com> Date: Tue, 29 Jan 2019 11:03:56 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 MIME-Version: 1.0 In-Reply-To: <20190128145617.069b3a5436fc7e34bdebb104@linux-foundation.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Tue, 29 Jan 2019 10:03:58 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28.01.19 23:56, Andrew Morton wrote: > On Mon, 28 Jan 2019 14:53:09 -0800 Andrew Morton wrote: > >> On Fri, 25 Jan 2019 08:58:33 +0100 Oscar Salvador wrote: >> >>> On Wed, Jan 23, 2019 at 11:33:56AM +0100, David Hildenbrand wrote: >>>> If you use {} for the else case, please also do so for the if case. >>> >>> Diff on top: >>> >>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >>> index 25aee4f04a72..d5810e522b72 100644 >>> --- a/mm/memory_hotplug.c >>> +++ b/mm/memory_hotplug.c >>> @@ -1338,9 +1338,9 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end) >>> struct page *head = compound_head(page); >>> >>> if (hugepage_migration_supported(page_hstate(head)) && >>> - page_huge_active(head)) >>> + page_huge_active(head)) { >>> return pfn; >>> - else { >>> + } else { >>> unsigned long skip; >>> >>> skip = (1 << compound_order(head)) - (page - head); >>> >> >> The indenting is getting a bit deep also, so how about this? >> >> static unsigned long scan_movable_pages(unsigned long start, unsigned long end) >> { >> unsigned long pfn; >> >> for (pfn = start; pfn < end; pfn++) { >> struct page *page, *head; >> >> if (!pfn_valid(pfn)) >> continue; >> page = pfn_to_page(pfn); >> if (PageLRU(page)) >> return pfn; >> if (__PageMovable(page)) >> return pfn; >> >> if (!PageHuge(page)) >> continue; >> head = compound_head(page); >> if (hugepage_migration_supported(page_hstate(head)) && >> page_huge_active(head)) { >> return pfn; > > checkpatch pointed out that else-after-return isn't needed so we can do > > static unsigned long scan_movable_pages(unsigned long start, unsigned long end) > { > unsigned long pfn; > > for (pfn = start; pfn < end; pfn++) { > struct page *page, *head; > unsigned long skip; > > if (!pfn_valid(pfn)) > continue; > page = pfn_to_page(pfn); > if (PageLRU(page)) > return pfn; > if (__PageMovable(page)) > return pfn; > > if (!PageHuge(page)) > continue; > head = compound_head(page); > if (hugepage_migration_supported(page_hstate(head)) && > page_huge_active(head)) > return pfn; > skip = (1 << compound_order(head)) - (page - head); > pfn += skip - 1; > } > return 0; > } > > --- a/mm/memory_hotplug.c~mmmemory_hotplug-fix-scan_movable_pages-for-gigantic-hugepages-fix > +++ a/mm/memory_hotplug.c > @@ -1305,28 +1305,27 @@ int test_pages_in_a_zone(unsigned long s > static unsigned long scan_movable_pages(unsigned long start, unsigned long end) > { > unsigned long pfn; > - struct page *page; > + > for (pfn = start; pfn < end; pfn++) { > - if (pfn_valid(pfn)) { > - page = pfn_to_page(pfn); > - if (PageLRU(page)) > - return pfn; > - if (__PageMovable(page)) > - return pfn; > - if (PageHuge(page)) { > - struct page *head = compound_head(page); > + struct page *page, *head; > + unsigned long skip; > > - if (hugepage_migration_supported(page_hstate(head)) && > - page_huge_active(head)) > - return pfn; > - else { > - unsigned long skip; > + if (!pfn_valid(pfn)) > + continue; > + page = pfn_to_page(pfn); > + if (PageLRU(page)) > + return pfn; > + if (__PageMovable(page)) > + return pfn; > > - skip = (1 << compound_order(head)) - (page - head); > - pfn += skip - 1; > - } > - } > - } > + if (!PageHuge(page)) > + continue; > + head = compound_head(page); > + if (hugepage_migration_supported(page_hstate(head)) && > + page_huge_active(head)) > + return pfn; > + skip = (1 << compound_order(head)) - (page - head); > + pfn += skip - 1; Not sure if encoding the -1 in the previous line is even better now that we have more space skip = (1 << compound_order(head)) - (page - head + 1); Looks good to me. > } > return 0; > } > _ > -- Thanks, David / dhildenb