qspawn: allow configurable limiters

And bump the default limit to 32 so we match git-daemon
behavior.  This shall allow us to configure different levels
of concurrency for different repositories and prevent clones
of giant repos from stalling service to small repos.

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/PublicInbox/GitHTTPBackend.pm b/lib/PublicInbox/GitHTTPBackend.pm
index ebb0850a..ed8fdf00 100644
--- a/lib/PublicInbox/GitHTTPBackend.pm
+++ b/lib/PublicInbox/GitHTTPBackend.pm
@@ -13,6 +13,9 @@ use HTTP::Status qw(status_message);
 use Plack::Util;
 use PublicInbox::Qspawn;
 
+# 32 is same as the git-daemon connection limit
+my $default_limiter = PublicInbox::Qspawn::Limiter->new(32);
+
 # n.b. serving "description" and "cloneurl" should be innocuous enough to
 # not cause problems.  serving "config" might...
 my @text = qw[HEAD info/refs
@@ -176,6 +179,7 @@ sub prepare_range {
 # returns undef if 403 so it falls back to dumb HTTP
 sub serve_smart {
         my ($env, $git, $path) = @_;
+        my $limiter = $default_limiter;
         my $in = $env->{'psgi.input'};
         my $fd = eval { fileno($in) };
         unless (defined $fd && $fd >= 0) {
@@ -248,7 +252,7 @@ sub serve_smart {
                 # holding the input here is a waste of FDs and memory
                 $env->{'psgi.input'} = undef;
 
-                $x->start(sub { # may run later, much later...
+                $x->start($limiter, sub { # may run later, much later...
                         ($rpipe) = @_;
                         $in = undef;
                         if ($async) {