ipc: get rid of -ipc_ppid field in favor of fork_gen

We own all the `fork' calls in our codebase, so rely on the
existing $PublicInbox::OnDestroy::fork_gen instead of using `$$'
to call getpid(2) everywhere.  getpid(2) is slower nowadays
since it's always a syscall on modern glibc whereas it was
cached (somewhat unsafely) in the past.

diff --git a/lib/PublicInbox/IPC.pm b/lib/PublicInbox/IPC.pm
index 9e4fa96b43096fb8d37a15c2ff6576074859851f..db313104dda5ebb6d5d8bb97582cf9b0e4921ffc 100644 (file)
--- a/lib/PublicInbox/IPC.pm
+++ b/lib/PublicInbox/IPC.pm
@@ -100,8 +100,8 @@ sub exit_exception { exit(!!$@) }
 # starts a worker if Sereal or Storable is installed
 sub ipc_worker_spawn {
        my ($self, $ident, $oldset, $fields, @cb_args) = @_;
-       return if ($self->{-ipc_ppid} // -1) == $$; # idempotent
-       delete(@$self{qw(-ipc_req -ipc_res -ipc_ppid -ipc_pid)});
+       return if $self->{-ipc_res} && $self->{-ipc_res}->can_reap; # idempotent
+       delete(@$self{qw(-ipc_req -ipc_res -ipc_pid)});
        pipe(my $r_req, my $w_req);
        pipe(my $r_res, my $w_res);
        my $sigset = $oldset // PublicInbox::DS::block_signals();
@@ -132,7 +132,6 @@ sub ipc_worker_spawn {
        $self->{-ipc_req} = $w_req;
        $self->{-ipc_res} = PublicInbox::IO::attach_pid($r_res, $pid,
                                        \&ipc_worker_reap, $self, @cb_args);
-       $self->{-ipc_ppid} = $$;
        $self->{-ipc_pid} = $pid;
 }
 
@@ -160,7 +159,7 @@ sub ipc_atfork_child {
 # idempotent, can be called regardless of whether worker is active or not
 sub ipc_worker_stop {
        my ($self) = @_;
-       my ($pid, $ppid) = delete(@$self{qw(-ipc_pid -ipc_ppid)});
+       my $pid = delete $self->{-ipc_pid};
        my ($w_req, $r_res) = delete(@$self{qw(-ipc_req -ipc_res)});
        if (!$w_req && !$r_res) {
                die "unexpected PID:$pid without IPC pipes" if $pid;
@@ -198,7 +197,7 @@ sub ipc_do {
 # causes newer siblings to inherit older siblings sockets
 sub ipc_sibling_atfork_child {
        my ($self) = @_;
-       my ($pid, undef) = delete(@$self{qw(-ipc_pid -ipc_ppid)});
+       my $pid = delete $self->{-ipc_pid};
        delete(@$self{qw(-ipc_req -ipc_res)});
        $pid == $$ and die "BUG: $$ ipc_atfork_child called on itself";
 }