Re: [PATCH v2] fadvise: introduce POSIX_FADV_DONTNEED_FS

On Wed, Apr 27, 2011 at 14:13, Andrea Righi wrote:

Introduce a new fadvise flag to drop page cache pages of a single
filesystem.

At the moment it is possible to drop page cache pages via
/proc/sys/vm/drop_pagecache or via posix_fadvise(POSIX_FADV_DONTNEED).

The first method drops the whole page cache while the second can be used
to drop page cache pages of a single file descriptor. However, there's
not a simple way to drop all the pages of a filesystem (we could scan
all the file descriptors and use posix_fadvise(POSIX_FADV_DONTNEED), but
this solution obviously doesn't scale well).

what if you open the mount point and use POSIX_FADV_DONTNEED on that
dir handle ?  if you required write access for that level, it'd also
implicitly take care of the permission issue.  but maybe this is just
trying to fit existing code in the wrong way.
-mike