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GET /api/patches/806914/?format=api
{ "id": 806914, "url": "http://patchwork.ozlabs.org/api/patches/806914/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/1503972142-289376-2-git-send-email-pasha.tatashin@oracle.com/", "project": { "id": 2, "url": "http://patchwork.ozlabs.org/api/projects/2/?format=api", "name": "Linux PPC development", "link_name": "linuxppc-dev", "list_id": "linuxppc-dev.lists.ozlabs.org", "list_email": "linuxppc-dev@lists.ozlabs.org", "web_url": "https://github.com/linuxppc/wiki/wiki", "scm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git", "webscm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/", "list_archive_url": "https://lore.kernel.org/linuxppc-dev/", "list_archive_url_format": "https://lore.kernel.org/linuxppc-dev/{}/", "commit_url_format": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id={}" }, "msgid": "<1503972142-289376-2-git-send-email-pasha.tatashin@oracle.com>", "list_archive_url": "https://lore.kernel.org/linuxppc-dev/1503972142-289376-2-git-send-email-pasha.tatashin@oracle.com/", "date": "2017-08-29T02:02:12", "name": "[v7,01/11] x86/mm: setting fields in deferred pages", "commit_ref": null, "pull_url": null, "state": "not-applicable", "archived": false, "hash": "2d5d3bebc38f0d67a851ce48186714a85e374654", "submitter": { "id": 71010, "url": "http://patchwork.ozlabs.org/api/people/71010/?format=api", "name": "Pavel Tatashin", "email": "pasha.tatashin@oracle.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/1503972142-289376-2-git-send-email-pasha.tatashin@oracle.com/mbox/", "series": [ { "id": 286, "url": "http://patchwork.ozlabs.org/api/series/286/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=286", "date": "2017-08-29T02:02:21", "name": "complete deferred page initialization", "version": 7, "mbox": "http://patchwork.ozlabs.org/series/286/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/806914/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/806914/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org>", "X-Original-To": [ "patchwork-incoming@ozlabs.org", "linuxppc-dev@lists.ozlabs.org" ], "Delivered-To": [ "patchwork-incoming@ozlabs.org", "linuxppc-dev@lists.ozlabs.org" ], "Received": [ "from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3])\n\t(using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xhBwR6nXsz9s1h\n\tfor <patchwork-incoming@ozlabs.org>;\n\tTue, 29 Aug 2017 12:12:07 +1000 (AEST)", "from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3])\n\tby lists.ozlabs.org (Postfix) with ESMTP id 3xhBwR5ddCzDqjP\n\tfor <patchwork-incoming@ozlabs.org>;\n\tTue, 29 Aug 2017 12:12:07 +1000 (AEST)", "from aserp1040.oracle.com (aserp1040.oracle.com [141.146.126.69])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256\n\tbits)) (No client certificate requested)\n\tby lists.ozlabs.org (Postfix) with ESMTPS id 3xhBkh3MbHzDqLm\n\tfor <linuxppc-dev@lists.ozlabs.org>;\n\tTue, 29 Aug 2017 12:03:40 +1000 (AEST)", "from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233])\n\tby aserp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2)\n\twith ESMTP id v7T22XoA011010\n\t(version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256\n\tverify=OK); Tue, 29 Aug 2017 02:02:33 GMT", "from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236])\n\tby aserv0021.oracle.com (8.14.4/8.14.4) with ESMTP id\n\tv7T22Wu2005146\n\t(version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256\n\tverify=OK); Tue, 29 Aug 2017 02:02:33 GMT", "from abhmp0011.oracle.com (abhmp0011.oracle.com [141.146.116.17])\n\tby aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id\n\tv7T22SVS010235; Tue, 29 Aug 2017 02:02:28 GMT", "from ca-ldom-ol-build-1.us.oracle.com (/10.129.68.23)\n\tby default (Oracle Beehive Gateway v4.0)\n\twith ESMTP ; Mon, 28 Aug 2017 19:02:28 -0700" ], "From": "Pavel Tatashin <pasha.tatashin@oracle.com>", "To": "linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org,\n\tlinux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,\n\tlinux-s390@vger.kernel.org, linux-arm-kernel@lists.infradead.org,\n\tx86@kernel.org, kasan-dev@googlegroups.com, borntraeger@de.ibm.com,\n\theiko.carstens@de.ibm.com, davem@davemloft.net, willy@infradead.org, \n\tmhocko@kernel.org, ard.biesheuvel@linaro.org, will.deacon@arm.com,\n\tcatalin.marinas@arm.com, sam@ravnborg.org, mgorman@techsingularity.net,\n\tSteven.Sistare@oracle.com, daniel.m.jordan@oracle.com,\n\tbob.picco@oracle.com", "Subject": "[PATCH v7 01/11] x86/mm: setting fields in deferred pages", "Date": "Mon, 28 Aug 2017 22:02:12 -0400", "Message-Id": "<1503972142-289376-2-git-send-email-pasha.tatashin@oracle.com>", "X-Mailer": "git-send-email 1.7.1", "In-Reply-To": "<1503972142-289376-1-git-send-email-pasha.tatashin@oracle.com>", "References": "<1503972142-289376-1-git-send-email-pasha.tatashin@oracle.com>", "X-Source-IP": "aserv0021.oracle.com [141.146.126.233]", "X-BeenThere": "linuxppc-dev@lists.ozlabs.org", "X-Mailman-Version": "2.1.23", "Precedence": "list", "List-Id": "Linux on PowerPC Developers Mail List\n\t<linuxppc-dev.lists.ozlabs.org>", "List-Unsubscribe": "<https://lists.ozlabs.org/options/linuxppc-dev>,\n\t<mailto:linuxppc-dev-request@lists.ozlabs.org?subject=unsubscribe>", "List-Archive": "<http://lists.ozlabs.org/pipermail/linuxppc-dev/>", "List-Post": "<mailto:linuxppc-dev@lists.ozlabs.org>", "List-Help": "<mailto:linuxppc-dev-request@lists.ozlabs.org?subject=help>", "List-Subscribe": "<https://lists.ozlabs.org/listinfo/linuxppc-dev>,\n\t<mailto:linuxppc-dev-request@lists.ozlabs.org?subject=subscribe>", "Errors-To": "linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org", "Sender": "\"Linuxppc-dev\"\n\t<linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org>" }, "content": "Without deferred struct page feature (CONFIG_DEFERRED_STRUCT_PAGE_INIT),\nflags and other fields in \"struct page\"es are never changed prior to first\ninitializing struct pages by going through __init_single_page().\n\nWith deferred struct page feature enabled, however, we set fields in\nregister_page_bootmem_info that are subsequently clobbered right after in\nfree_all_bootmem:\n\n mem_init() {\n register_page_bootmem_info();\n free_all_bootmem();\n ...\n }\n\nWhen register_page_bootmem_info() is called only non-deferred struct pages\nare initialized. But, this function goes through some reserved pages which\nmight be part of the deferred, and thus are not yet initialized.\n\n mem_init\n register_page_bootmem_info\n register_page_bootmem_info_node\n get_page_bootmem\n .. setting fields here ..\n such as: page->freelist = (void *)type;\n\n free_all_bootmem()\n free_low_memory_core_early()\n for_each_reserved_mem_region()\n reserve_bootmem_region()\n init_reserved_page() <- Only if this is deferred reserved page\n __init_single_pfn()\n __init_single_page()\n memset(0) <-- Loose the set fields here\n\nWe end-up with issue where, currently we do not observe problem as memory\nis explicitly zeroed. But, if flag asserts are changed we can start hitting\nissues.\n\nAlso, because in this patch series we will stop zeroing struct page memory\nduring allocation, we must make sure that struct pages are properly\ninitialized prior to using them.\n\nThe deferred-reserved pages are initialized in free_all_bootmem().\nTherefore, the fix is to switch the above calls.\n\nSigned-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>\nReviewed-by: Steven Sistare <steven.sistare@oracle.com>\nReviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>\nReviewed-by: Bob Picco <bob.picco@oracle.com>\n---\n arch/x86/mm/init_64.c | 9 +++++++--\n 1 file changed, 7 insertions(+), 2 deletions(-)", "diff": "diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c\nindex 62a91e6b1237..3a997352a992 100644\n--- a/arch/x86/mm/init_64.c\n+++ b/arch/x86/mm/init_64.c\n@@ -1174,12 +1174,17 @@ void __init mem_init(void)\n \n \t/* clear_bss() already clear the empty_zero_page */\n \n-\tregister_page_bootmem_info();\n-\n \t/* this will put all memory onto the freelists */\n \tfree_all_bootmem();\n \tafter_bootmem = 1;\n \n+\t/* Must be done after boot memory is put on freelist, because here we\n+\t * might set fields in deferred struct pages that have not yet been\n+\t * initialized, and free_all_bootmem() initializes all the reserved\n+\t * deferred pages for us.\n+\t */\n+\tregister_page_bootmem_info();\n+\n \t/* Register memory areas for /proc/kcore */\n \tkclist_add(&kcore_vsyscall, (void *)VSYSCALL_ADDR,\n \t\t\t PAGE_SIZE, KCORE_OTHER);\n", "prefixes": [ "v7", "01/11" ] }