From patchwork Mon May 25 14:19:11 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Konstantin Khlebnikov X-Patchwork-Id: 11568883 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 223FA14B7 for ; Mon, 25 May 2020 14:19:19 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D937A208B3 for ; Mon, 25 May 2020 14:19:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=yandex-team.ru header.i=@yandex-team.ru header.b="0tuAg8ST" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D937A208B3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=yandex-team.ru Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C1CC88003A; Mon, 25 May 2020 10:19:17 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id BA7078E0008; Mon, 25 May 2020 10:19:17 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A6EA28003A; Mon, 25 May 2020 10:19:17 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0185.hostedemail.com [216.40.44.185]) by kanga.kvack.org (Postfix) with ESMTP id 882228E0008 for ; Mon, 25 May 2020 10:19:17 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 406DD2485 for ; Mon, 25 May 2020 14:19:17 +0000 (UTC) X-FDA: 76855448754.21.teeth59_33d2b11b73441 X-Spam-Summary: 2,0,0,cd8f9c1310d6d447,d41d8cd98f00b204,khlebnikov@yandex-team.ru,,RULES_HIT:41:152:355:379:800:960:966:973:988:989:1260:1277:1311:1313:1314:1345:1437:1515:1516:1518:1535:1544:1593:1594:1711:1730:1747:1777:1792:1801:2194:2196:2198:2199:2200:2201:2393:2559:2562:2731:2892:3138:3139:3140:3141:3142:3355:3865:3866:3867:3868:3870:3871:3872:3873:4117:4321:4385:4605:5007:6119:6261:6653:7901:7903:9010:9163:9207:10004:11026:11232:11473:11657:11658:11914:12043:12291:12297:12438:12517:12519:12555:12679:12760:12895:12986:13869:13870:14181:14394:14687:14721:14922:21080:21324:21433:21451:21627:21939:21987:21990:30005:30029:30045:30054:30070:30075,0,RBL:95.108.205.193:@yandex-team.ru:.lbl8.mailshell.net-66.100.201.201 62.2.3.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:136,LUA_SUMMARY:none X-HE-Tag: teeth59_33d2b11b73441 X-Filterd-Recvd-Size: 6621 Received: from forwardcorp1o.mail.yandex.net (forwardcorp1o.mail.yandex.net [95.108.205.193]) by imf46.hostedemail.com (Postfix) with ESMTP for ; Mon, 25 May 2020 14:19:15 +0000 (UTC) Received: from mxbackcorp1j.mail.yandex.net (mxbackcorp1j.mail.yandex.net [IPv6:2a02:6b8:0:1619::162]) by forwardcorp1o.mail.yandex.net (Yandex) with ESMTP id 8B9292E148C; Mon, 25 May 2020 17:19:13 +0300 (MSK) Received: from sas2-32987e004045.qloud-c.yandex.net (sas2-32987e004045.qloud-c.yandex.net [2a02:6b8:c08:b889:0:640:3298:7e00]) by mxbackcorp1j.mail.yandex.net (mxbackcorp/Yandex) with ESMTP id TE2c15HR0I-JBT4gn4f; Mon, 25 May 2020 17:19:13 +0300 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1590416353; bh=9PK2yRmXiCHZqxdLDHJm4JhQRlB9fTwJMpmWFICGZKs=; h=Message-ID:Date:To:From:Subject:Cc; b=0tuAg8STSm9az6HjEPgKxgoUxtFXGLQU+srV4JyMACYQcrpfXkyRNiaw4nCA8pO9S 8oinh8DC3E6SfTPN057WLGTsIb1ldh9Lb1xRCd1c+RHVkQoYPt1I2GPOjxP56vAlo6 aQXBr1cQaz2HyH7ylQ3vPcw4qNof4JM9I7/sKW2U= Authentication-Results: mxbackcorp1j.mail.yandex.net; dkim=pass header.i=@yandex-team.ru Received: from dynamic-vpn.dhcp.yndx.net (dynamic-vpn.dhcp.yndx.net [2a02:6b8:b081:603::1:c]) by sas2-32987e004045.qloud-c.yandex.net (smtpcorp/Yandex) with ESMTPSA id YD1YIbjaQW-JBWqln8N; Mon, 25 May 2020 17:19:11 +0300 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (Client certificate not present) Subject: [PATCH] mm: dump_page: add debugfs file for dumping page state by pfn From: Konstantin Khlebnikov To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton Cc: Vlastimil Babka , "Kirill A. Shutemov" Date: Mon, 25 May 2020 17:19:11 +0300 Message-ID: <159041635119.987025.7321864888027213705.stgit@buzz> User-Agent: StGit/0.22-39-gd257 MIME-Version: 1.0 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: Tool 'page-types' could list pages mapped by process or file cache pages, but it shows only limited amount of state exported via procfs. Let's employ existing helper dump_page() to reach remaining information: writing pfn into /sys/kernel/debug/dump_page dumps state into kernel log. # echo 0x37c43c > /sys/kernel/debug/dump_page # dmesg | tail -6 page:ffffcb0b0df10f00 refcount:1 mapcount:0 mapping:000000007755d3d9 index:0x30 0xffffffffae4239e0 name:"libGeoIP.so.1.6.9" flags: 0x200000000020014(uptodate|lru|mappedtodisk) raw: 0200000000020014 ffffcb0b187fd288 ffffcb0b189e6248 ffff9528a04afe10 raw: 0000000000000030 0000000000000000 00000001ffffffff 0000000000000000 page dumped because: debugfs request With CONFIG_PAGE_OWNER=y shows also stacks for last page alloc and free: page:ffffea0018fff480 refcount:1 mapcount:1 mapping:0000000000000000 index:0x7f9f28f62 anon flags: 0x100000000080034(uptodate|lru|active|swapbacked) raw: 0100000000080034 ffffea00184140c8 ffffea0018517d88 ffff8886076ba161 raw: 00000007f9f28f62 0000000000000000 0000000100000000 ffff888bfc79f000 page dumped because: debugfs request page->mem_cgroup:ffff888bfc79f000 page_owner tracks the page as allocated page last allocated via order 0, migratetype Movable, gfp_mask 0x100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO) prep_new_page+0x139/0x1a0 get_page_from_freelist+0xde9/0x14e0 __alloc_pages_nodemask+0x18b/0x360 alloc_pages_vma+0x7c/0x270 __handle_mm_fault+0xd40/0x12b0 handle_mm_fault+0xe7/0x1e0 do_page_fault+0x2d5/0x610 page_fault+0x2f/0x40 page last free stack trace: free_pcp_prepare+0x11e/0x1c0 free_unref_page_list+0x71/0x180 release_pages+0x31e/0x480 tlb_flush_mmu+0x44/0x150 tlb_finish_mmu+0x3d/0x70 exit_mmap+0xdd/0x1a0 mmput+0x70/0x140 do_exit+0x33f/0xc40 do_group_exit+0x3a/0xa0 __x64_sys_exit_group+0x14/0x20 do_syscall_64+0x48/0x130 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Signed-off-by: Konstantin Khlebnikov Acked-by: Kirill A. Shutemov --- Documentation/admin-guide/mm/pagemap.rst | 3 +++ Documentation/vm/page_owner.rst | 10 ++++++++++ mm/debug.c | 27 +++++++++++++++++++++++++++ 3 files changed, 40 insertions(+) diff --git a/Documentation/admin-guide/mm/pagemap.rst b/Documentation/admin-guide/mm/pagemap.rst index 340a5aee9b80..663ad5490d72 100644 --- a/Documentation/admin-guide/mm/pagemap.rst +++ b/Documentation/admin-guide/mm/pagemap.rst @@ -205,3 +205,6 @@ Before Linux 3.11 pagemap bits 55-60 were used for "page-shift" (which is always 12 at most architectures). Since Linux 3.11 their meaning changes after first clear of soft-dirty bits. Since Linux 4.2 they are used for flags unconditionally. + +Page state could be dumped into kernel log by writing pfn in text form +into /sys/kernel/debug/dump_page. diff --git a/Documentation/vm/page_owner.rst b/Documentation/vm/page_owner.rst index 0ed5ab8c7ab4..d4d4dc64c19d 100644 --- a/Documentation/vm/page_owner.rst +++ b/Documentation/vm/page_owner.rst @@ -88,3 +88,13 @@ Usage See the result about who allocated each page in the ``sorted_page_owner.txt``. + +Notes +===== + +To lookup pages in file cache or mapped in process you could use interface +pagemap documented in Documentation/admin-guide/mm/pagemap.rst or tool +page-types in the tools/vm directory. + +Page state could be dumped into kernel log by writing pfn in text form +into /sys/kernel/debug/dump_page. diff --git a/mm/debug.c b/mm/debug.c index 2189357f0987..5803f2b63d95 100644 --- a/mm/debug.c +++ b/mm/debug.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "internal.h" @@ -147,6 +148,32 @@ void dump_page(struct page *page, const char *reason) } EXPORT_SYMBOL(dump_page); +#ifdef CONFIG_DEBUG_FS +static int dump_page_set(void *data, u64 pfn) +{ + struct page *page; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + page = pfn_to_online_page(pfn); + if (!page) + return -ENXIO; + + dump_page(page, "debugfs request"); + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE(dump_page_fops, NULL, dump_page_set, "%llx\n"); + +static int __init dump_page_debugfs(void) +{ + debugfs_create_file_unsafe("dump_page", 0200, NULL, NULL, + &dump_page_fops); + return 0; +} +late_initcall(dump_page_debugfs); +#endif /* CONFIG_DEBUG_FS */ + #ifdef CONFIG_DEBUG_VM void dump_vma(const struct vm_area_struct *vma)