From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: John Hubbard <jhubbard@nvidia.com>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
"Al Viro" <viro@zeniv.linux.org.uk>,
"Christoph Hellwig" <hch@infradead.org>,
"Dan Williams" <dan.j.williams@intel.com>,
"Dave Chinner" <david@fromorbit.com>,
"Ira Weiny" <ira.weiny@intel.com>, "Jan Kara" <jack@suse.cz>,
"Jason Gunthorpe" <jgg@ziepe.ca>,
"Jonathan Corbet" <corbet@lwn.net>,
"Jérôme Glisse" <jglisse@redhat.com>,
"Michal Hocko" <mhocko@suse.com>,
"Mike Kravetz" <mike.kravetz@oracle.com>,
"Shuah Khan" <shuah@kernel.org>,
"Vlastimil Babka" <vbabka@suse.cz>,
"Matthew Wilcox" <willy@infradead.org>,
linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kselftest@vger.kernel.org, linux-rdma@vger.kernel.org,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH v6 12/12] mm: dump_page(): additional diagnostics for huge pinned pages
Date: Tue, 11 Feb 2020 16:21:59 +0300 [thread overview]
Message-ID: <20200211132159.pii2x5pssifemgaz@box> (raw)
In-Reply-To: <20200211001536.1027652-13-jhubbard@nvidia.com>
On Mon, Feb 10, 2020 at 04:15:36PM -0800, John Hubbard wrote:
> 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.
>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Matthew Wilcox <willy@infradead.org>
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
> ---
> Documentation/core-api/pin_user_pages.rst | 7 +++++++
> mm/debug.c | 21 ++++++++++++++++-----
> 2 files changed, 23 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/core-api/pin_user_pages.rst b/Documentation/core-api/pin_user_pages.rst
> index 5c8a5f89756b..2e939ff10b86 100644
> --- a/Documentation/core-api/pin_user_pages.rst
> +++ b/Documentation/core-api/pin_user_pages.rst
> @@ -238,6 +238,13 @@ long-term [R]DMA pins in place, or during pin/unpin transitions.
> (...unless it was already out of balance due to a long-term RDMA pin being in
> place.)
>
> +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 f5ffb0784559..2189357f0987 100644
> --- a/mm/debug.c
> +++ b/mm/debug.c
> @@ -85,11 +85,22 @@ void __dump_page(struct page *page, const char *reason)
> mapcount = PageSlab(head) ? 0 : page_mapcount(page);
>
> if (compound)
> - pr_warn("page:%px refcount:%d mapcount:%d mapping:%p "
> - "index:%#lx head:%px order:%u compound_mapcount:%d\n",
> - page, page_ref_count(head), mapcount,
> - mapping, page_to_pgoff(page), head,
> - compound_order(head), compound_mapcount(page));
> + if (hpage_pincount_available(page)) {
> + pr_warn("page:%px refcount:%d mapcount:%d mapping:%p "
> + "index:%#lx head:%px order:%u "
> + "compound_mapcount:%d compound_pincount:%d\n",
> + page, page_ref_count(head), mapcount,
> + mapping, page_to_pgoff(page), head,
> + compound_order(head), compound_mapcount(page),
> + compound_pincount(page));
> + } else {
> + pr_warn("page:%px refcount:%d mapcount:%d mapping:%p "
> + "index:%#lx head:%px order:%u "
> + "compound_mapcount:%d\n",
> + page, page_ref_count(head), mapcount,
> + mapping, page_to_pgoff(page), head,
> + compound_order(head), compound_mapcount(page));
> + }
Have you considered using pr_cont() here. I guess it would be easier to
read.
You can use my Ack anyway.
> else
> pr_warn("page:%px refcount:%d mapcount:%d mapping:%p index:%#lx\n",
> page, page_ref_count(page), mapcount,
> --
> 2.25.0
>
--
Kirill A. Shutemov
next prev parent reply other threads:[~2020-02-11 13:21 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-11 0:15 [PATCH v6 00/12] mm/gup: track FOLL_PIN pages John Hubbard
2020-02-11 0:15 ` [PATCH v6 01/12] mm/gup: split get_user_pages_remote() into two routines John Hubbard
2020-02-11 0:15 ` [PATCH v6 02/12] mm/gup: pass a flags arg to __gup_device_* functions John Hubbard
2020-02-11 0:15 ` [PATCH v6 03/12] mm: introduce page_ref_sub_return() John Hubbard
2020-02-11 0:15 ` [PATCH v6 04/12] mm/gup: pass gup flags to two more routines John Hubbard
2020-02-11 0:15 ` [PATCH v6 05/12] mm/gup: require FOLL_GET for get_user_pages_fast() John Hubbard
2020-02-11 0:15 ` [PATCH v6 06/12] mm/gup: track FOLL_PIN pages John Hubbard
2020-04-24 18:18 ` [regression] " Alex Williamson
2020-04-24 19:20 ` John Hubbard
2020-04-24 20:15 ` Alex Williamson
2020-04-24 22:58 ` John Hubbard
2020-04-28 16:54 ` [regression?] " Alex Williamson
2020-04-28 17:49 ` Jason Gunthorpe
2020-04-28 19:07 ` Alex Williamson
2020-04-28 19:22 ` Jason Gunthorpe
2020-04-28 20:12 ` Alex Williamson
2020-04-29 0:29 ` Jason Gunthorpe
2020-04-29 19:56 ` Alex Williamson
2020-04-29 23:03 ` Jason Gunthorpe
2020-02-11 0:15 ` [PATCH v6 07/12] mm/gup: page->hpage_pinned_refcount: exact pin counts for huge pages John Hubbard
2020-02-11 0:15 ` [PATCH v6 08/12] mm/gup: /proc/vmstat: pin_user_pages (FOLL_PIN) reporting John Hubbard
2020-02-12 9:17 ` Jan Kara
2020-02-11 0:15 ` [PATCH v6 09/12] mm/gup_benchmark: support pin_user_pages() and related calls John Hubbard
2020-02-11 0:15 ` [PATCH v6 10/12] selftests/vm: run_vmtests: invoke gup_benchmark with basic FOLL_PIN coverage John Hubbard
2020-02-11 0:15 ` [PATCH v6 11/12] mm: Improve dump_page() for compound pages John Hubbard
2020-02-11 0:15 ` [PATCH v6 12/12] mm: dump_page(): additional diagnostics for huge pinned pages John Hubbard
2020-02-11 13:21 ` Kirill A. Shutemov [this message]
2020-02-12 2:10 ` John Hubbard
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