inboxidle: avoid needless syscalls on refresh

[public-inbox.git] / lib / PublicInbox / InboxIdle.pm

diff --git a/lib/PublicInbox/InboxIdle.pm b/lib/PublicInbox/InboxIdle.pm
index 357bd216b5c30642fef65c84bbd343053d53ec25..60948bea72c2a03e21331691bd8db9fe9b465acf 100644 (file)
--- a/lib/PublicInbox/InboxIdle.pm
+++ b/lib/PublicInbox/InboxIdle.pm
@@ -30,17 +30,26 @@ sub in2_arm ($$) { # PublicInbox::Config::each_inbox callback
        }
        my $inot = $self->{inot};
        my $cur = $self->{pathmap}->{$dir} //= [];
+       my $lock = "$dir/".($ibx->version >= 2 ? 'inbox.lock' : 'ssoma.lock');
 
        # transfer old subscriptions to the current inbox, cancel the old watch
-       if (my $old_ibx = $cur->[0]) {
+       my $old_ibx = $cur->[0];
+       $cur->[0] = $ibx;
+       if ($old_ibx) {
                $ibx->{unlock_subs} and
                        die "BUG: $dir->{unlock_subs} should not exist";
                $ibx->{unlock_subs} = $old_ibx->{unlock_subs};
+
+               # Linux::Inotify2::Watch::name matches if watches are the
+               # same, no point in replacing a watch of the same name
+               if ($cur->[1]->name eq $lock) {
+                       $self->{on_unlock}->{$lock} = $ibx;
+                       return;
+               }
+               # rare, name changed (v1 inbox converted to v2)
                $cur->[1]->cancel; # Linux::Inotify2::Watch::cancel
        }
-       $cur->[0] = $ibx;
 
-       my $lock = "$dir/".($ibx->version >= 2 ? 'inbox.lock' : 'ssoma.lock');
        if (my $w = $cur->[1] = $inot->watch($lock, $IN_MODIFY)) {
                $self->{on_unlock}->{$w->name} = $ibx;
        } else {