Commit ef18a1ca authored Oct 18, 2019 by Kirill A. Shutemov Committed by Linus Torvalds Oct 19, 2019

mm/thp: allow dropping THP from page cache

Once a THP is added to the page cache, it cannot be dropped via
/proc/sys/vm/drop_caches.  Fix this issue with proper handling in
invalidate_mapping_pages().

Link: http://lkml.kernel.org/r/20191017164223.2762148-5-songliubraving@fb.com


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

parent 906d278d

mm/truncate.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -592,6 +592,16 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping,
		unlock_page(page);
		continue;
		}

		/* Take a pin outside pagevec */
		get_page(page);

		/*
		* Drop extra pins before trying to invalidate
		* the huge page.
		*/
		pagevec_remove_exceptionals(&pvec);
		pagevec_release(&pvec);
		}

		ret = invalidate_inode_page(page);
		@@ -602,6 +612,8 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping,
		*/
		if (!ret)
		deactivate_file_page(page);
		if (PageTransHuge(page))
		put_page(page);
		count += ret;
		}
		pagevec_remove_exceptionals(&pvec);

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