suse man page for unmap_mapping_range

UNMAP_MAPPING_RANGE(9)					    Memory Management in Linux					    UNMAP_MAPPING_RANGE(9)

NAME
       unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the
       underlying file.

SYNOPSIS
       void unmap_mapping_range(struct address_space * mapping, loff_t const holebegin, loff_t const holelen, int even_cows);

ARGUMENTS
       mapping
	   the address space containing mmaps to be unmapped.

       holebegin
	   byte in first page to unmap, relative to the start of the underlying file. This will be rounded down to a PAGE_SIZE boundary. Note that
	   this is different from truncate_pagecache, which must keep the partial page. In contrast, we must get rid of partial pages.

       holelen
	   size of prospective hole in bytes. This will be rounded up to a PAGE_SIZE boundary. A holelen of zero truncates to the end of the file.

       even_cows
	   1 when truncating a file, unmap even private COWed pages; but 0 when invalidating pagecache, don't throw away private data.

COPYRIGHT
Kernel Hackers Manual 2.6.					     July 2010						    UNMAP_MAPPING_RANGE(9)