829ae0f81c
The issue is reported when removing memory through virtio_mem device. The transparent huge page, experienced copy-on-write fault, is wrongly regarded as pinned. The transparent huge page is escaped from being isolated in isolate_migratepages_block(). The transparent huge page can't be migrated and the corresponding memory block can't be put into offline state. Fix it by replacing page_mapcount() with total_mapcount(). With this, the transparent huge page can be isolated and migrated, and the memory block can be put into offline state. Besides, The page's refcount is increased a bit earlier to avoid the page is released when the check is executed. Link: https://lkml.kernel.org/r/20221124095523.31061-1-gshan@redhat.com Fixes: 1da2f328fa64 ("mm,thp,compaction,cma: allow THP migration for CMA allocations") Signed-off-by: Gavin Shan <gshan@redhat.com> Reported-by: Zhenyu Zhang <zhenyzha@redhat.com> Tested-by: Zhenyu Zhang <zhenyzha@redhat.com> Suggested-by: David Hildenbrand <david@redhat.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: William Kucharski <william.kucharski@oracle.com> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> [5.7+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.