From patchwork Fri Feb 7 03:37:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Hubbard X-Patchwork-Id: 11369671 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 039CB186E for ; Fri, 7 Feb 2020 03:38:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BB9F122464 for ; Fri, 7 Feb 2020 03:38:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="ef/4udRo" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BB9F122464 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 274FC6B0070; Thu, 6 Feb 2020 22:37:43 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 1D6546B0071; Thu, 6 Feb 2020 22:37:43 -0500 (EST) 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 F1E396B0072; Thu, 6 Feb 2020 22:37:42 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id BC6346B0070 for ; Thu, 6 Feb 2020 22:37:42 -0500 (EST) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 706888248047 for ; Fri, 7 Feb 2020 03:37:42 +0000 (UTC) X-FDA: 76461921564.06.heart42_6052bdac1414f X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,jhubbard@nvidia.com,:akpm@linux-foundation.org:viro@zeniv.linux.org.uk:hch@infradead.org:dan.j.williams@intel.com:david@fromorbit.com:ira.weiny@intel.com:jack@suse.cz:jgg@ziepe.ca:corbet@lwn.net:jglisse@redhat.com:kirill@shutemov.name:mhocko@suse.com:mike.kravetz@oracle.com:shuah@kernel.org:vbabka@suse.cz:willy@infradead.org:linux-doc@vger.kernel.org:linux-fsdevel@vger.kernel.org:linux-kselftest@vger.kernel.org:linux-rdma@vger.kernel.org::linux-kernel@vger.kernel.org:jhubbard@nvidia.com:kirill.shutemov@linux.intel.com,RULES_HIT:30054:30064:30090,0,RBL:216.228.121.143:@nvidia.com:.lbl8.mailshell.net-62.18.0.100 64.10.201.10,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:24,LUA_SUMMARY:none X-HE-Tag: heart42_6052bdac1414f X-Filterd-Recvd-Size: 6886 Received: from hqnvemgate24.nvidia.com (hqnvemgate24.nvidia.com [216.228.121.143]) by imf39.hostedemail.com (Postfix) with ESMTP for ; Fri, 7 Feb 2020 03:37:41 +0000 (UTC) Received: from hqpgpgate102.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Thu, 06 Feb 2020 19:36:38 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate102.nvidia.com (PGP Universal service); Thu, 06 Feb 2020 19:37:38 -0800 X-PGP-Universal: processed; by hqpgpgate102.nvidia.com on Thu, 06 Feb 2020 19:37:38 -0800 Received: from HQMAIL111.nvidia.com (172.20.187.18) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Fri, 7 Feb 2020 03:37:37 +0000 Received: from hqnvemgw03.nvidia.com (10.124.88.68) by HQMAIL111.nvidia.com (172.20.187.18) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Fri, 7 Feb 2020 03:37:37 +0000 Received: from blueforge.nvidia.com (Not Verified[10.110.48.28]) by hqnvemgw03.nvidia.com with Trustwave SEG (v7,5,8,10121) id ; Thu, 06 Feb 2020 19:37:37 -0800 From: John Hubbard To: Andrew Morton CC: Al Viro , Christoph Hellwig , Dan Williams , Dave Chinner , Ira Weiny , Jan Kara , Jason Gunthorpe , Jonathan Corbet , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , "Kirill A . Shutemov" , Michal Hocko , Mike Kravetz , Shuah Khan , Vlastimil Babka , Matthew Wilcox , , , , , , LKML , John Hubbard , "Kirill A . Shutemov" Subject: [PATCH v5 09/12] mm: dump_page(): better diagnostics for huge pinned pages Date: Thu, 6 Feb 2020 19:37:32 -0800 Message-ID: <20200207033735.308000-10-jhubbard@nvidia.com> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200207033735.308000-1-jhubbard@nvidia.com> References: <20200207033735.308000-1-jhubbard@nvidia.com> MIME-Version: 1.0 X-NVConfidentiality: public DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1581046599; bh=jmOUjzJ549EfFTXaNo+IqA1m0L9Edt0hTMtlZOuZ9oI=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:X-NVConfidentiality: Content-Transfer-Encoding:Content-Type; b=ef/4udRoouVf31SNt8dxH8rGemdY2KQ3FUhL1foXTZbDgzP4IyhLK4YjOkoH8c4J7 vZIBhMUtt/Q4ked+2xEBrgqdgHxMVPEsMO+ZlJHNnQBUA0b/dN7rEQuPkTfxV5Iz+m YwMe+ClfugPn1gCR754PWzgyqnw3AwyYFOcqRCqkmf5o2pBbdcO5A8xjcfl4on2s17 zxAj6h1KNcrH4VfNdeKRUNav6fFaca+k9pEYjlc5vne5iyY9kswBj9/R7pYLkzXyQ4 Vp5jnRVUcRp0yCDbFslLV8IXO7B+toifjZo7qM2L5LOadtrhiHvkBEE9Lq9NvmG1A3 7txFYKNBc41Kg== 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: As part of pin_user_pages() and related API calls, pages are "dma-pinned". For the case of compound pages of order > 1, the per-page accounting of dma pins is accomplished via the 3rd struct page in the compound page. In order to support debugging of any pin_user_pages()- related problems, enhance dump_page() so as to report the pin count in that case. Documentation/core-api/pin_user_pages.rst is also updated accordingly. Acked-by: Kirill A. Shutemov Reviewed-by: Jan Kara Signed-off-by: John Hubbard --- Documentation/core-api/pin_user_pages.rst | 7 +++++ mm/debug.c | 34 +++++++++++++++++------ 2 files changed, 33 insertions(+), 8 deletions(-) diff --git a/Documentation/core-api/pin_user_pages.rst b/Documentation/core-api/pin_user_pages.rst index 7e5dd8b1b3f2..24641f1a1eba 100644 --- a/Documentation/core-api/pin_user_pages.rst +++ b/Documentation/core-api/pin_user_pages.rst @@ -215,6 +215,13 @@ Those are both going to show zero, unless CONFIG_DEBUG_VM is set. This is because there is a noticeable performance drop in unpin_user_page(), when they are activated. +Other diagnostics +================= + +dump_page() has been enhanced slightly, to handle these new counting fields, and +to better report on compound pages in general. Specifically, for compound pages +with order > 1, the exact (hpage_pinned_refcount) pincount is reported. + References ========== diff --git a/mm/debug.c b/mm/debug.c index f074077eee11..e82c878c27df 100644 --- a/mm/debug.c +++ b/mm/debug.c @@ -57,10 +57,20 @@ static void __dump_tail_page(struct page *page, int mapcount) page, page_ref_count(page), mapcount, page->mapping, page_to_pgoff(page)); } else { - pr_warn("page:%px compound refcount:%d mapcount:%d mapping:%px " - "index:%#lx compound_mapcount:%d\n", - page, page_ref_count(head), mapcount, head->mapping, - page_to_pgoff(head), compound_mapcount(page)); + if (hpage_pincount_available(page)) + pr_warn("page:%px compound refcount:%d mapcount:%d " + "mapping:%px index:%#lx compound_mapcount:%d " + "compound_pincount:%d\n", + page, page_ref_count(head), mapcount, + head->mapping, page_to_pgoff(head), + compound_mapcount(page), + compound_pincount(page)); + else + pr_warn("page:%px compound refcount:%d mapcount:%d " + "mapping:%px index:%#lx compound_mapcount:%d\n", + page, page_ref_count(head), mapcount, + head->mapping, page_to_pgoff(head), + compound_mapcount(page)); } if (page_ref_count(page) != 0) { @@ -104,10 +114,18 @@ void __dump_page(struct page *page, const char *reason) if (PageTail(page)) __dump_tail_page(page, mapcount); - else - pr_warn("page:%px refcount:%d mapcount:%d mapping:%px index:%#lx\n", - page, page_ref_count(page), mapcount, - page->mapping, page_to_pgoff(page)); + else { + if (hpage_pincount_available(page)) + pr_warn("page:%px refcount:%d mapcount:%d mapping:%px " + "index:%#lx compound pincount: %d\n", + page, page_ref_count(page), mapcount, + page->mapping, page_to_pgoff(page), + compound_pincount(page)); + else + pr_warn("page:%px refcount:%d mapcount:%d mapping:%px " + "index:%#lx\n", page, page_ref_count(page), + mapcount, page->mapping, page_to_pgoff(page)); + } if (PageKsm(page)) type = "ksm "; else if (PageAnon(page))