From bf929e8ddfb9359a97cd8be3d3017c038564d52d Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Sat, 30 Sep 2023 15:20:38 +0000 Subject: [PATCH] git: decouple cat_async_retry from POSIX pipe semantics While pipes guarantee writes of <= 512 bytes to be atomic, Unix stream sockets (or TCP sockets) have no such guarantees. Removing the pipe assumption will make it possible for us to switch to bidirectional Unix stream sockets and save FDs with `git cat-file' processes as we have with Gcf2Client. The performance benefit of larger pipe buffers over stream sockets isn't irrelevant when interacting with git as it is with SearchIdx shards. --- lib/PublicInbox/Git.pm | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) diff --git a/lib/PublicInbox/Git.pm b/lib/PublicInbox/Git.pm index eb88aa489..8ac40d2b9 100644 --- a/lib/PublicInbox/Git.pm +++ b/lib/PublicInbox/Git.pm @@ -223,25 +223,21 @@ sub my_readline ($$) { } sub cat_async_retry ($$) { - my ($self, $inflight) = @_; + my ($self, $old_inflight) = @_; # {inflight} may be non-existent, but if it isn't we delete it # here to prevent cleanup() from waiting: delete $self->{inflight}; cleanup($self); + batch_prepare($self, my $new_inflight = []); - batch_prepare($self, $inflight); - my $buf = ''; - for (my $i = 0; $i < @$inflight; $i += 3) { - $buf .= "$inflight->[$i]\n"; + while (my ($oid, $cb, $arg) = splice(@$old_inflight, 0, 3)) { + write_all($self, $self->{out}, $oid."\n", + \&cat_async_step, $new_inflight); + $oid = \$oid if !@$new_inflight; # to indicate oid retried + push @$new_inflight, $oid, $cb, $arg; } - $self->{out}->blocking(1); # brand new pipe, should never block - print { $self->{out} } $buf or $self->fail("write error: $!"); - $self->{out}->blocking(0); - my $req = shift @$inflight; - unshift(@$inflight, \$req); # \$ref to indicate retried - - cat_async_step($self, $inflight); # take one step + cat_async_step($self, $new_inflight); # take one step } # returns true if prefetch is successful -- 2.47.2