From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jakub Narebski <jnareb@gmail.com>
Subject: Re: [RFC PATCHv2 09/10] gitweb/cache.pm - Regenerate (refresh) cache in background
Date: Tue, 9 Feb 2010 23:23:17 +0100
Message-ID: <201002092323.24832.jnareb@gmail.com>
References: <1265711427-15193-1-git-send-email-jnareb@gmail.com> <1265711427-15193-10-git-send-email-jnareb@gmail.com>
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Cc: John 'Warthog9' Hawley <warthog9@eaglescrag.net>,
	John 'Warthog9' Hawley <warthog9@kernel.org>,
	Petr Baudis <pasky@suse.cz>
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On Tue, 9 Feb 2010, Jakub Narebski wrote:

[...]
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0my $pid =3D fork() if (=
$data && $self->get_background_cache());
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0if (!defined $pid || $p=
id) {
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
# parent, or didn't fork
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
$data =3D $p_coderef->($self, $p_key);
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
$self->set($p_key, $data);
> +
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
if ($pid) {
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0=A0=A0=A0# releases lock before waiting and exiting
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0=A0=A0=A0close $lock_fh;
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0=A0=A0=A0# wait for child (which would print) and exit
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0=A0=A0=A0waitpid $pid, 0;
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0=A0=A0=A0exit 0;
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
}
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0} else {
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
# child is to serve stale data
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
return $data;
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0}
[...]

I have decide to rely on $SIG{CHLD} =3D 'IGNORE' to not generate zombie=
s,
and consistently exit in child (in forked process) and return in parent=
=2E
This change would be in next version of this series.

--=20
Jakub Narebski
Poland