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authorJohn Hubbard <jhubbard@nvidia.com>2020-04-02 07:05:52 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-04-02 19:35:27 +0300
commitdc8fb2f282ad13e550b65958fea40c7eb766d42a (patch)
treed458eec3753014cccb95fb95c87ff34985c759b3 /mm/debug.c
parent6197ab984b4190d79cf5ccf39b25868730e83e2b (diff)
downloadlinux-dc8fb2f282ad13e550b65958fea40c7eb766d42a.tar.xz
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>
Diffstat (limited to 'mm/debug.c')
-rw-r--r--mm/debug.c21
1 files changed, 16 insertions, 5 deletions
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,