WordPress bug? – get_permalink

I’m debugging a plugin (Google XML sitemaps by A. Brachold) trying to spot the memory allocation problem on large sitemaps.

As a result I have detected that the problem apparently lies into a call to a WP function:

$permalink = get_permalink($post->ID);

The statement above is placed into a loop; on a 1,000 rows (posts) loop, the function, “leaks” some 4MB of memory.

Is this a well-known behavior or should I open a bug track?