diff options
| author | John Hubbard <jhubbard@nvidia.com> | 2020-04-01 21:05:52 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-04-02 09:35:27 -0700 |
| commit | dc8fb2f282ad13e550b65958fea40c7eb766d42a (patch) | |
| tree | d458eec3753014cccb95fb95c87ff34985c759b3 | |
| parent | 6197ab984b4190d79cf5ccf39b25868730e83e2b (diff) | |
mm: dump_page(): additional diagnostics for huge pinned pages
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/20200211001536.1027652-13-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | Documentation/core-api/pin_user_pages.rst | 7 | ||||
| -rw-r--r-- | 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)); + } else pr_warn("page:%px refcount:%d mapcount:%d mapping:%p index:%#lx\n", page, page_ref_count(page), mapcount, |