Increasing/decreasing workers count will be useful in
some situations.
---
lib/PublicInbox/IPC.pm | 99 ++++++++++++++++++++++++++++++------------
t/ipc.t | 9 ++++
2 files changed, 81 insertions(+), 27 deletions(-)
diff --git a/lib/PublicInbox/IPC.pm b/lib/PublicInbox/IPC.pm
index 0c5205c1..5bca3627 100644
--- a/lib/PublicInbox/IPC.pm
+++ b/lib/PublicInbox/IPC.pm
@@ -8,7 +8,7 @@ use v5.10.1;
use Carp qw(confess croak);
use PublicInbox::DS qw(dwaitpid);
use PublicInbox::Spawn;
-use POSIX ();
+use POSIX qw(WNOHANG);
use Socket qw(AF_UNIX MSG_EOR);
my $SEQPACKET = eval { Socket::SOCK_SEQPACKET() }; # portable enough?
use constant PIPE_BUF => $^O eq 'linux' ? 4096 : POSIX::_POSIX_PIPE_BUF();
@@ -112,7 +112,7 @@ sub ipc_worker_spawn {
$w_res->autoflush(1);
$SIG{$_} = 'IGNORE' for (qw(TERM INT QUIT));
local $0 = $ident;
- PublicInbox::DS::sig_setmask($oldset);
+ PublicInbox::DS::sig_setmask($sigset);
my $on_destroy = $self->ipc_atfork_child;
eval { ipc_worker_loop($self, $r_req, $w_res) };
die "worker $ident PID:$$ died: $@\n" if $@;
@@ -229,12 +229,13 @@ sub ipc_sibling_atfork_child {
$pid == $$ and die "BUG: $$ ipc_atfork_child called on itself";
}
-sub wq_worker_loop ($$) {
- my ($self, $s2) = @_;
+sub wq_worker_loop ($) {
+ my ($self) = @_;
my $buf;
my $len = $self->{wq_req_len} // (4096 * 33);
my ($rec, $sub, @args);
- while (1) {
+ my $s2 = $self->{-wq_s2} // die 'BUG: no -wq_s2';
+ until ($self->{-wq_quit}) {
my (@fds) = $recv_cmd->($s2, $buf, $len) or return; # EOF
my $i = 0;
my @m = @{$self->{wq_open_modes} // [qw( +<&= >&= >&= )]};
@@ -258,7 +259,7 @@ sub wq_worker_loop ($$) {
sub wq_do { # always async
my ($self, $sub, $in, $out, $err, @args) = @_;
- if (my $s1 = $self->{-wq_seq}) { # run in worker
+ if (my $s1 = $self->{-wq_s1}) { # run in worker
$_ = fileno($_) for ($in, $out, $err);
$send_cmd->($s1, $in, $out, $err,
freeze([$sub, @args]), MSG_EOR);
@@ -270,42 +271,86 @@ sub wq_do { # always async
}
}
+sub _wq_worker_start ($$) {
+ my ($self, $oldset) = @_;
+ my $pid = fork // die "fork: $!";
+ if ($pid == 0) {
+ eval { PublicInbox::DS->Reset };
+ close(delete $self->{-wq_s1});
+ delete $self->{qw(-wq_workers -wq_quit)};
+ my $quit = sub { $self->{-wq_quit} = 1 };
+ $SIG{$_} = $quit for (qw(TERM INT QUIT));
+ $SIG{$_} = 'IGNORE' for (qw(TTOU TTIN));
+ local $0 = $self->{-wq_ident};
+ PublicInbox::DS::sig_setmask($oldset);
+ my $on_destroy = $self->ipc_atfork_child;
+ eval { wq_worker_loop($self) };
+ die "worker $self->{-wq_ident} PID:$$ died: $@\n" if $@;
+ exit;
+ } else {
+ $self->{-wq_workers}->{$pid} = \undef;
+ }
+}
+
# starts workqueue workers if Sereal or Storable is installed
sub wq_workers_start {
my ($self, $ident, $nr_workers, $oldset) = @_;
($enc && $send_cmd && $recv_cmd && defined($SEQPACKET)) or return;
- return if $self->{-wq_seq}; # idempotent
+ return if $self->{-wq_s1}; # idempotent
my ($s1, $s2);
socketpair($s1, $s2, AF_UNIX, $SEQPACKET, 0) or die "socketpair: $!";
- my $sigset = $oldset // PublicInbox::DS::block_signals();
$self->ipc_atfork_parent;
$nr_workers //= 4;
+ my $sigset = $oldset // PublicInbox::DS::block_signals();
$self->{-wq_workers} = {};
- for my $i (0..($nr_workers - 1)) {
- defined(my $pid = fork) or die "fork: $!";
- if ($pid == 0) {
- eval { PublicInbox::DS->Reset };
- $s1 = undef;
- $SIG{$_} = 'IGNORE' for (qw(TERM INT QUIT));
- local $0 = $ident."[$i]";
- PublicInbox::DS::sig_setmask($oldset);
- my $on_destroy = $self->ipc_atfork_child;
- eval { wq_worker_loop($self, $s2) };
- die "worker $ident PID:$$ died: $@\n" if $@;
- exit;
- } else {
- $self->{-wq_workers}->{$pid} = $i;
- }
- }
+ $self->{-wq_ident} = $ident;
+ $self->{-wq_s1} = $s1;
+ $self->{-wq_s2} = $s2;
+ _wq_worker_start($self, $sigset) for (1..$nr_workers);
PublicInbox::DS::sig_setmask($sigset) unless $oldset;
- $s2 = undef;
- $self->{-wq_seq} = $s1;
$self->{-wq_ppid} = $$;
}
+sub wq_worker_incr { # SIGTTIN handler
+ my ($self, $oldset) = @_;
+ $self->{-wq_s2} or return;
+ $self->ipc_atfork_parent;
+ my $sigset = $oldset // PublicInbox::DS::block_signals();
+ _wq_worker_start($self, $sigset);
+ PublicInbox::DS::sig_setmask($sigset) unless $oldset;
+}
+
+sub wq_exit { # wakes up wq_worker_decr_wait
+ send($_[0]->{-wq_s2}, $$, MSG_EOR) // die "$$ send: $!";
+ exit;
+}
+
+sub wq_worker_decr { # SIGTTOU handler, kills first idle worker
+ my ($self) = @_;
+ my $workers = $self->{-wq_workers} or return;
+ my $s2 = $self->{-wq_s2} // die 'BUG: no wq_s2';
+ $self->wq_do('wq_exit', $s2, $s2, $s2);
+ $self->{-wq_exit_pending}++;
+ # caller must call wq_worker_decr_wait in main loop
+}
+
+sub wq_worker_decr_wait {
+ my ($self, $timeout) = @_;
+ return if $self->{-wq_ppid} != $$; # can't reap siblings or parents
+ my $s1 = $self->{-wq_s1} // croak 'BUG: no wq_s1';
+ vec(my $rin = '', fileno($s1), 1) = 1;
+ select(my $rout = $rin, undef, undef, $timeout) or
+ croak 'timed out waiting for wq_exit';
+ recv($s1, my $pid, 64, 0) // croak "recv: $!";
+ my $workers = $self->{-wq_workers} // croak 'BUG: no wq_workers';
+ delete $workers->{$pid} // croak "BUG: PID:$pid invalid";
+ $self->{-wq_exit_pending}--;
+ dwaitpid($pid, \&ipc_worker_reap, $self);
+}
+
sub wq_close {
my ($self) = @_;
- delete $self->{-wq_seq} or return;
+ delete @$self{qw(-wq_s1 -wq_s2)} or return;
my $ppid = delete $self->{-wq_ppid} // die 'BUG: no wq_ppid';
my $workers = delete $self->{-wq_workers} // die 'BUG: no wq_workers';
return if $ppid != $$; # can't reap siblings or parents
diff --git a/t/ipc.t b/t/ipc.t
index f09f76ef..51e347c6 100644
--- a/t/ipc.t
+++ b/t/ipc.t
@@ -168,4 +168,13 @@ like($warn[0], qr/ wq_do: /, '1st warned from wq_do');
like($warn[1], qr/ wq_worker: /, '2nd warned from wq_worker');
is($warn[2], $warn[1], 'worker did not die');
+$SIG{__WARN__} = 'DEFAULT';
+is($ipc->wq_workers_start('wq', 1), $$, 'workers started again');
+is(scalar(keys %{$ipc->{-wq_workers}}), 1, '1 worker started');
+$ipc->wq_worker_incr;
+is(scalar(keys %{$ipc->{-wq_workers}}), 2, 'worker count bumped');
+$ipc->wq_worker_decr;
+$ipc->wq_worker_decr_wait(10);
+is(scalar(keys %{$ipc->{-wq_workers}}), 1, 'worker count lowered');
+
done_testing;
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