Re: [PATCH 0/13] maps: pagemap, kpagemap, and related cleanups

William Lee Irwin III
2007-04-12T23:10:38Z

On Tue, Apr 03, 2007 at 09:43:30PM -0500, Matt Mackall wrote:
> This patch series introduces /proc/pid/pagemap and /proc/kpagemap,
> which allow detailed run-time examination of process memory usage at a
> page granularity.
> The first several patches whip the page-walking code introduced for
> /proc/pid/smaps and clear_refs into a more generic form, the next
> couple make those interfaces optional, and the last two introduce the
> new interfaces, also optional.

This solves a real-life problem for Oracle system monitoring software
(specifically EM). Among the tasks it must carry out is determining
per-process memory footprint of a set of cooperating tasks (i.e. Oracle
processes). RSS is inadequate for this due to page sharing; this work
provides sufficient information to determine what EM needs.

-- wli