shrink low-bandwidth pipes under Linux

I've hit /proc/sys/fs/pipe-user-pages-* limits on some systems.
So stop hogging resources on pipes which don't benefit from
giant sizes.

Some of these can use eventfd in the future to further reduce
resource use.

1 files changed, 4 insertions, 0 deletions

diff --git a/lib/PublicInbox/EvCleanup.pm b/lib/PublicInbox/EvCleanup.pm
index 1a3a3d5e..1a2bdb29 100644
--- a/lib/PublicInbox/EvCleanup.pm
+++ b/lib/PublicInbox/EvCleanup.pm
@@ -19,7 +19,11 @@ my $laterq = [ [], undef ];
 sub once_init () {
         my $self = fields::new('PublicInbox::EvCleanup');
         my ($r, $w);
+
+        # This is a dummy pipe which is always writable so it can always
+        # fires in the next event loop iteration.
         pipe($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..
         $self;