ds: stop caring about event flags set by epoll/poll/kqueue

If we got something to write, then write it.  Otherwise, try
reading; and continue dealing with errors which normally occur
along the way.

Trying to read requests while we need to buffer in luserspace
is suicidal from a memory management standpoint.

The only adjustment needed for existing callers is EvCleanup;
where we need to ensure we're always calling the dummy
EvCleanup::event_write callback to accomplish nothing.

1 files changed, 6 insertions, 2 deletions

diff --git a/lib/PublicInbox/EvCleanup.pm b/lib/PublicInbox/EvCleanup.pm
index afed24ff..f76fb681 100644
--- a/lib/PublicInbox/EvCleanup.pm
+++ b/lib/PublicInbox/EvCleanup.pm
@@ -6,7 +6,6 @@ package PublicInbox::EvCleanup;
 use strict;
 use warnings;
 use base qw(PublicInbox::DS);
-use fields qw(rd);
 
 my $ENABLED;
 sub enabled { $ENABLED }
@@ -25,7 +24,12 @@ sub once_init () {
         pipe($r, $w) or die "pipe: $!";
         fcntl($w, 1031, 4096) if $^O eq 'linux'; # 1031: F_SETPIPE_SZ
         $self->SUPER::new($w);
-        $self->{rd} = $r; # never read, since we never write..
+
+        # always writable, since PublicInbox::EvCleanup::event_write
+        # never drains wbuf.  We can avoid wasting a hash slot by
+        # stuffing the read-end of the pipe into the never-to-be-touched
+        # wbuf
+        push @{$self->{wbuf}}, $r;
         $self;
 }