On Sun, 10 Sep 2000, Matt Sergeant wrote:
> For 2 days solid now I've been trying to track down a very bizarre memory
> leak in AxKit.
>
> I've checked everything I can think of - all circular references are now
> gone, all closures clean up carefully after themselves, and I've reduced
> the usage of some external modules. But still the processes grow.
>
> Now to the wierd bit. I could track this down if it wasn't for this:
>
> The memory leak starts after the Nth hit, usually around 35. This is
> running under httpd -X.
>
> So it goes along very happily for 35 hits - memory usage is rock solid
> stable. Then after the 35th hit the memory usage starts to grow about 4k
> per hit. Obviously thats an impossible rate of growth to sustain for any
> amount of time, and soon the server is swamped.
you're leaking on every request, consider this example:
use strict;
my $i = 0;
my @a;
my $old_size = proc_size();
while (++$i) {
my $size = proc_size();
if ($size != $old_size) {
printf "Size changed from $old_size to $size, i=$i\n";
$old_size = $size;
<>; #pause
}
push @a, [];
}
sub proc_size {
my $size = 0;
open my $fh, "</proc/self/status";
while (<$fh>) {
last if (($size) = (/^VmRSS:\s+(\d+)/));
}
close $fh;
$size;
}
outputs:
Size changed from 1376 to 1436, i=1
Size changed from 1436 to 1472, i=2
Size changed from 1472 to 1476, i=55
Size changed from 1476 to 1480, i=99
Size changed from 1480 to 1484, i=158
Size changed from 1484 to 1488, i=204
> Time::HiRes, Apache::* (core apache stuff only), AxKit, Digest::MD5,
> Compress::Zlib, Fcntl, XML::Parser, XML::XPath, Unicode::Map8,
> Unicode::String, MIME::Base64, Storable (loaded but not used),
> XML::Sablotron (loaded but not used).
look for xsubs in those modules you're using that are calling
new{SV,AV,HV,RV} or SvREFCNT_inc(). sounds like botched refcnting or
failure to mortalize a new*V.
actually, my first guess is Apache::ModuleConfig->get, if you don't
explicitly pass __PACKAGE__ as the last argument, perl_eval_pv() is
called, which has a leak plugged in perl-current:
[ 6201] By: gsar on 2000/06/06 00:42:59
Log: Perl_eval_pv() leaks 4 bytes every time it is called because it
does a PUSHMARK that's never ever POPMARKed; in general, only
Perl_call_[sp]v() need a PUSHMARK for incoming arguments;
Perl_eval_[sp]v() don't because they don't take any incoming
arguments (this leak has been around since the original version
of perl_eval_pv() in 5.003_97e)
Branch: perl
! perl.c
so first try changing:
Apache::ModuleConfig->get($r)
to
Apache::ModuleConfig->get($r, __PACKAGE__)
