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* [PATCH 09/22] ipc: wq: support dynamic worker count change
  2021-01-10 12:14  7% [PATCH 00/22] lei query overview views Eric Wong
@ 2021-01-10 12:15  5% ` Eric Wong
  0 siblings, 0 replies; 2+ results
From: Eric Wong @ 2021-01-10 12:15 UTC (permalink / raw)
  To: meta

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;

^ permalink raw reply related	[relevance 5%]

* [PATCH 00/22] lei query overview views
@ 2021-01-10 12:14  7% Eric Wong
  2021-01-10 12:15  5% ` [PATCH 09/22] ipc: wq: support dynamic worker count change Eric Wong
  0 siblings, 1 reply; 2+ results
From: Eric Wong @ 2021-01-10 12:14 UTC (permalink / raw)
  To: meta

Usage summary:

	lei add-external /path/to/v1-or-v2-inbox
	lei add-external /path/to/another-inbox-or-ext-index
			# URLs aren't supported, yet :<

	lei q SEARCH TERMS GO HERE... # pager should open with JSON output

For faster startup time than what Inline::C can give:

	apt-get install libsocket-msghdr-perl # Socket::Msghdr

Having neither Inline::C nor Socket::Msghdr means parallel
queries won't work.

I went back-and-forth on a bunch of things but ultimately gave
up trying to support IO::FDPass since it got too fragile and
difficult to test with the work-queue distribution.

The pager runs from the client process (if using Socket::MsgHdr
or Inline::C), now.  It took at fair amount of work from my slow
brain to get pager shutdown to be instantaneous, though queries
which haven't output anything aren't easily interruptible...

The wq_* IPC stuff will be reused in the normal read-only
WWW/IMAP search at some point, too.

Eric Wong (22):
  lei query + pagination sorta working
  lei q: deduplicate smsg
  ds: block signals when reaping
  ipc: add support for asynchronous callbacks
  cmd_ipc: send FDs with buffer payload
  ipc: avoid excessive evals
  ipc: work queue support via SOCK_SEQPACKET
  ipc: eliminate ipc_worker_stop method
  ipc: wq: support dynamic worker count change
  ipc: drop -ipc_parent_pid field
  ipc: DESTROY and wq_workers methods
  lei: rename $w to $wpager for warning message
  lei: fix oneshot TTY detection by passing STD*{GLOB}
  lei: query: ensure pager exit is instantaneous
  ipc: start supporting sending/receiving more than 3 FDs
  ipc: fix IO::FDPass use with a worker limit of 1
  ipc: drop unused fields, default sighandlers for wq
  lei: get rid of client {pid} field
  lei: fork + FD cleanup
  lei: run pager in client script
  lei_xsearch: transfer 4 FDs internally, drop IO::FDPass
  lei: query: restore JSON output overview

 MANIFEST                        |   4 +
 lib/PublicInbox/CmdIPC4.pm      |  36 ++++
 lib/PublicInbox/DS.pm           |  16 +-
 lib/PublicInbox/Daemon.pm       |  10 +-
 lib/PublicInbox/ExtSearchIdx.pm |   4 +-
 lib/PublicInbox/IPC.pm          | 280 ++++++++++++++++++++++++++++----
 lib/PublicInbox/LEI.pm          | 180 +++++++++++++-------
 lib/PublicInbox/LeiDedupe.pm    |  29 +++-
 lib/PublicInbox/LeiExternal.pm  |  33 ++--
 lib/PublicInbox/LeiOverview.pm  | 188 +++++++++++++++++++++
 lib/PublicInbox/LeiQuery.pm     |  92 +++++++++++
 lib/PublicInbox/LeiStore.pm     |   2 +-
 lib/PublicInbox/LeiToMail.pm    |   2 +
 lib/PublicInbox/LeiXSearch.pm   | 118 +++++++++++++-
 lib/PublicInbox/Search.pm       |  10 +-
 lib/PublicInbox/SearchView.pm   |  10 +-
 lib/PublicInbox/Sigfd.pm        |  12 +-
 lib/PublicInbox/Spawn.pm        |  85 ++++++----
 lib/PublicInbox/Watch.pm        |   8 +-
 script/lei                      |  76 +++++----
 script/public-inbox-watch       |   4 +-
 t/cmd_ipc.t                     |  82 ++++++++++
 t/ipc.t                         | 115 ++++++++++++-
 t/lei.t                         |  31 +++-
 t/lei_dedupe.t                  |  14 ++
 t/lei_xsearch.t                 |   5 +
 t/spawn.t                       |  33 +---
 27 files changed, 1233 insertions(+), 246 deletions(-)
 create mode 100644 lib/PublicInbox/CmdIPC4.pm
 create mode 100644 lib/PublicInbox/LeiOverview.pm
 create mode 100644 lib/PublicInbox/LeiQuery.pm
 create mode 100644 t/cmd_ipc.t

^ permalink raw reply	[relevance 7%]

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