I have found a bug with Apache::SizeLimit (Note: I am not referring to Apache2::SizeLimit -- although it may have the same problem).

PLATFORM BACKGROUND:
Mod_perl 1.29
Redhat EL5 (kernel 2.6.18)
Apache::SizeLimit version: $VERSION = '0.91-dev';
Perl version: 5.8.8

PROBLEM:
If I turn off USE_SMAPS (i.e. set Apache::SizeLimit::USE_SMAPS=0
), I get an error, specifically:

Can't call method "_linux_size_check" on an undefined value at /usr/lib64/perl5/site_perl/5.8.8/x86_64-linux-thread-multi/Apache/SizeLimit.pm line 216.

SOLUTION:
 A diff with my fix is shown below:

************************

@@ -161,7 +163,10 @@
 }

 sub _check_size {
-    my ( $size, $share ) = _platform_check_size();
+    my $class = shift;
+
+    my ( $size, $share ) = $class->_platform_check_size();

     return ( $size, $share, $size - $share );
 }

*************************
ADDITIONAL INFORMATION/QUESTION:

I ran into the problem above because I couldn't get smaps to work.  I had permission problems accessing the /proc/<pid>/smaps file.  It seems  that this file (and all others in the /proc/<pid> directory) is owned by root.  While /proc/<pid>/statm is viewable by everyone, /proc/<pid>/smaps is viewable only by root.  I don't know why.   The process itself is owned by 'web' -- the user that I have set to own apache child processes.  Perhaps the reason for root ownership is that the Apache parent process is owned by root and the child processes are only setuid to 'web'.  So, when the proc/<pid>/ files are made, the child processes are still owned by root.   But that wouldn't account for why smaps in particular is readable only by root.  Do you know of a way around this? Or if some kernel change in linux fixes this?

Thanks,
Jeremy