From 584f9a6e1e47fca4041ad5205f631197c2bafc59 Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Sat, 16 Oct 2021 09:29:53 +0000
Subject: lei sockets: favor level-triggered epoll for fairness

Sigfd->event_step needs priority over script/lei clients,
LeiSelfSocket, and everything else.
---
 lib/PublicInbox/LEI.pm           | 20 ++++++++------------
 lib/PublicInbox/LeiSelfSocket.pm | 27 +++++++++++----------------
 2 files changed, 19 insertions(+), 28 deletions(-)

diff --git a/lib/PublicInbox/LEI.pm b/lib/PublicInbox/LEI.pm
index 876598f9..6b989b33 100644
--- a/lib/PublicInbox/LEI.pm
+++ b/lib/PublicInbox/LEI.pm
@@ -12,13 +12,13 @@ use parent qw(PublicInbox::DS PublicInbox::LeiExternal
 	PublicInbox::LeiQuery);
 use Getopt::Long ();
 use Socket qw(AF_UNIX SOCK_SEQPACKET MSG_EOR pack_sockaddr_un);
-use Errno qw(EPIPE EAGAIN EINTR ECONNREFUSED ENOENT ECONNRESET);
+use Errno qw(EPIPE EAGAIN ECONNREFUSED ENOENT ECONNRESET);
 use Cwd qw(getcwd);
 use POSIX qw(strftime);
 use IO::Handle ();
 use Fcntl qw(SEEK_SET);
 use PublicInbox::Config;
-use PublicInbox::Syscall qw(EPOLLIN EPOLLET);
+use PublicInbox::Syscall qw(EPOLLIN);
 use PublicInbox::DS qw(now dwaitpid);
 use PublicInbox::Spawn qw(spawn popen_rd);
 use PublicInbox::Lock;
@@ -1125,16 +1125,12 @@ sub event_step {
 	local %ENV = %{$self->{env}};
 	local $current_lei = $self;
 	eval {
-		my $buf;
-		while (my @fds = $recv_cmd->($self->{sock}, $buf, 4096)) {
-			if (scalar(@fds) == 1 && !defined($fds[0])) {
-				return if $! == EAGAIN;
-				next if $! == EINTR;
-				last if $! == ECONNRESET;
-				die "recvmsg: $!";
-			}
-			for (@fds) { open my $rfh, '+<&=', $_ }
+		my @fds = $recv_cmd->($self->{sock}, my $buf, 4096);
+		if (scalar(@fds) == 1 && !defined($fds[0])) {
+			return if $! == EAGAIN;
+			die "recvmsg: $!" if $! != ECONNRESET;
 		}
+		for (@fds) { open my $rfh, '+<&=', $_ }
 		if ($buf eq '') {
 			_drop_wq($self); # EOF, client disconnected
 			dclose($self);
@@ -1162,7 +1158,7 @@ sub event_step_init {
 	my $sock = $self->{sock} or return;
 	$self->{-event_init_done} //= do { # persist til $ops done
 		$sock->blocking(0);
-		$self->SUPER::new($sock, EPOLLIN|EPOLLET);
+		$self->SUPER::new($sock, EPOLLIN);
 		$sock;
 	};
 }
diff --git a/lib/PublicInbox/LeiSelfSocket.pm b/lib/PublicInbox/LeiSelfSocket.pm
index 3d847649..dd64b6cf 100644
--- a/lib/PublicInbox/LeiSelfSocket.pm
+++ b/lib/PublicInbox/LeiSelfSocket.pm
@@ -10,7 +10,7 @@ use v5.10.1;
 use parent qw(PublicInbox::DS);
 use Data::Dumper;
 $Data::Dumper::Useqq = 1; # should've been the Perl default :P
-use PublicInbox::Syscall qw(EPOLLIN EPOLLET);
+use PublicInbox::Syscall qw(EPOLLIN);
 use PublicInbox::Spawn;
 my $recv_cmd;
 
@@ -20,26 +20,21 @@ sub new {
 	$r->blocking(0);
 	no warnings 'once';
 	$recv_cmd = $PublicInbox::LEI::recv_cmd;
-	$self->SUPER::new($r, EPOLLIN|EPOLLET);
+	$self->SUPER::new($r, EPOLLIN);
 }
 
 sub event_step {
 	my ($self) = @_;
-	while (1) {
-		my (@fds) = $recv_cmd->($self->{sock}, my $buf, 4096 * 33);
-		if (scalar(@fds) == 1 && !defined($fds[0])) {
-			return if $!{EAGAIN};
-			next if $!{EINTR};
-			die "recvmsg: $!";
-		}
-		# open so perl can auto-close them:
-		for my $fd (@fds) {
-			open(my $newfh, '+<&=', $fd) or die "open +<&=$fd: $!";
-		}
-		return $self->close if $buf eq '';
-		warn Dumper({ 'unexpected self msg' => $buf, fds => \@fds });
-		# TODO: figure out what to do with these messages...
+	my (@fds) = $recv_cmd->($self->{sock}, my $buf, 4096 * 33);
+	if (scalar(@fds) == 1 && !defined($fds[0])) {
+		return if $!{EAGAIN};
+		die "recvmsg: $!" unless $!{ECONNRESET};
+	} else { # just in case open so perl can auto-close them:
+		for (@fds) { open my $fh, '+<&=', $_ };
 	}
+	return $self->close if $buf eq '';
+	warn Dumper({ 'unexpected self msg' => $buf, fds => \@fds });
+	# TODO: figure out what to do with these messages...
 }
 
 1;
-- 
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