Commit 906d278d authored Oct 18, 2019 by William Kucharski Committed by Linus Torvalds Oct 19, 2019

mm/vmscan.c: support removing arbitrary sized pages from mapping

__remove_mapping() assumes that pages can only be either base pages or
HPAGE_PMD_SIZE.  Ask the page what size it is.

Link: http://lkml.kernel.org/r/20191017164223.2762148-4-songliubraving@fb.com


Fixes: 99cb0dbd ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Song Liu <songliubraving@fb.com>
Acked-by: Yang Shi <yang.shi@linux.alibaba.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 06d3eff6

mm/vmscan.c

+1 −4

Original line number	Diff line number	Diff line
		@@ -933,10 +933,7 @@ static int __remove_mapping(struct address_space mapping, struct page page,
		* Note that if SetPageDirty is always performed via set_page_dirty,
		* and thus under the i_pages lock, then this ordering is not required.
		*/
		if (unlikely(PageTransHuge(page)) && PageSwapCache(page))
		refcount = 1 + HPAGE_PMD_NR;
		else
		refcount = 2;
		refcount = 1 + compound_nr(page);
		if (!page_ref_freeze(page, refcount))
		goto cannot_free;
		/* note: atomic_cmpxchg in page_ref_freeze provides the smp_rmb */

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