TRUNCATE_INODE_PAGES(9)             Memory Management in Linux            TRUNCATE_INODE_PAGES(9)



NAME
       truncate_inode_pages_range - truncate range of pages specified by start & end byte offsets

SYNOPSIS
       void truncate_inode_pages_range(struct address_space * mapping, loff_t lstart,
                                       loff_t lend);

ARGUMENTS
       mapping
           mapping to truncate

       lstart
           offset from which to truncate

       lend
           offset to which to truncate (inclusive)

DESCRIPTION
       Truncate the page cache, removing the pages that are between specified offsets (and
       zeroing out partial pages if lstart or lend + 1 is not page aligned).

       Truncate takes two passes - the first pass is nonblocking. It will not block on page locks
       and it will not block on writeback. The second pass will wait. This is to prevent as much
       IO as possible in the affected region. The first pass will remove most pages, so the
       search cost of the second pass is low.

       We pass down the cache-hot hint to the page freeing code. Even if the mapping is large, it
       is probably the case that the final pages are the most recently touched, and freeing
       happens in ascending file offset order.

       Note that since ->invalidatepage accepts range to invalidate truncate_inode_pages_range is
       able to handle cases where lend + 1 is not page aligned properly.

COPYRIGHT
Kernel Hackers Manual 4.8.                 January 2017                   TRUNCATE_INODE_PAGES(9)