From: Jan Kara <jack@suse.cz>
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>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
"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>
Subject: Re: [PATCH v3 09/12] mm: dump_page(): better diagnostics for huge pinned pages
Date: Mon, 3 Feb 2020 15:44:48 +0100 [thread overview]
Message-ID: <20200203144448.GG18591@quack2.suse.cz> (raw)
In-Reply-To: <20200201034029.4063170-10-jhubbard@nvidia.com>
On Fri 31-01-20 19:40:26, 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.
>
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Looks good to me. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>
Honza
> ---
> 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 3f72b1ea1104..dd21ea140ef4 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 beb1c59d784b..db81b11345be 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)
> @@ -103,10 +113,18 @@ 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))
> --
> 2.25.0
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2020-02-03 14:44 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-01 3:40 [PATCH v3 00/12] mm/gup: track FOLL_PIN pages John Hubbard
2020-02-01 3:40 ` [PATCH v3 01/12] mm: dump_page(): better diagnostics for compound pages John Hubbard
2020-02-03 13:16 ` Kirill A. Shutemov
2020-02-03 19:51 ` John Hubbard
2020-02-01 3:40 ` [PATCH v3 02/12] mm/gup: split get_user_pages_remote() into two routines John Hubbard
2020-02-03 13:17 ` Kirill A. Shutemov
2020-02-03 14:20 ` Jan Kara
2020-02-03 21:09 ` John Hubbard
2020-02-01 3:40 ` [PATCH v3 03/12] mm/gup: pass a flags arg to __gup_device_* functions John Hubbard
2020-02-03 13:19 ` Kirill A. Shutemov
2020-02-03 19:56 ` John Hubbard
2020-02-01 3:40 ` [PATCH v3 04/12] mm: introduce page_ref_sub_return() John Hubbard
2020-02-03 13:23 ` Kirill A. Shutemov
2020-02-03 20:03 ` John Hubbard
2020-02-01 3:40 ` [PATCH v3 05/12] mm/gup: pass gup flags to two more routines John Hubbard
2020-02-03 13:24 ` Kirill A. Shutemov
2020-02-03 14:18 ` Jan Kara
2020-02-01 3:40 ` [PATCH v3 06/12] mm/gup: require FOLL_GET for get_user_pages_fast() John Hubbard
2020-02-03 13:26 ` Kirill A. Shutemov
2020-02-03 14:18 ` Jan Kara
2020-02-01 3:40 ` [PATCH v3 07/12] mm/gup: track FOLL_PIN pages John Hubbard
2020-02-03 13:40 ` Kirill A. Shutemov
2020-02-03 21:01 ` John Hubbard
2020-02-03 14:29 ` Jan Kara
2020-02-01 3:40 ` [PATCH v3 08/12] mm/gup: page->hpage_pinned_refcount: exact pin counts for huge pages John Hubbard
2020-02-03 13:45 ` Kirill A. Shutemov
2020-02-03 14:43 ` Jan Kara
2020-02-01 3:40 ` [PATCH v3 09/12] mm: dump_page(): better diagnostics for huge pinned pages John Hubbard
2020-02-03 13:46 ` Kirill A. Shutemov
2020-02-03 14:44 ` Jan Kara [this message]
2020-02-01 3:40 ` [PATCH v3 10/12] mm/gup: /proc/vmstat: pin_user_pages (FOLL_PIN) reporting John Hubbard
2020-02-03 13:53 ` Kirill A. Shutemov
2020-02-03 21:04 ` John Hubbard
2020-02-03 21:30 ` Kirill A. Shutemov
2020-02-03 21:34 ` John Hubbard
2020-02-03 23:16 ` John Hubbard
2020-02-03 23:43 ` John Hubbard
2020-02-01 3:40 ` [PATCH v3 11/12] mm/gup_benchmark: support pin_user_pages() and related calls John Hubbard
2020-02-03 13:58 ` Kirill A. Shutemov
2020-02-03 21:17 ` John Hubbard
2020-02-03 21:55 ` Kirill A. Shutemov
2020-02-03 22:07 ` John Hubbard
2020-02-01 3:40 ` [PATCH v3 12/12] selftests/vm: run_vmtests: invoke gup_benchmark with basic FOLL_PIN coverage John Hubbard
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200203144448.GG18591@quack2.suse.cz \
--to=jack@suse.cz \
--cc=akpm@linux-foundation.org \
--cc=corbet@lwn.net \
--cc=dan.j.williams@intel.com \
--cc=david@fromorbit.com \
--cc=hch@infradead.org \
--cc=ira.weiny@intel.com \
--cc=jgg@ziepe.ca \
--cc=jglisse@redhat.com \
--cc=jhubbard@nvidia.com \
--cc=kirill@shutemov.name \
--cc=linux-doc@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-rdma@vger.kernel.org \
--cc=mhocko@suse.com \
--cc=mike.kravetz@oracle.com \
--cc=shuah@kernel.org \
--cc=vbabka@suse.cz \
--cc=viro@zeniv.linux.org.uk \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).