user/dev discussion of public-inbox itself
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From: Eric Wong <e@80x24.org>
To: meta@public-inbox.org
Subject: [PATCH 55/57] ds: reimplement IO::Poll support to look like epoll
Date: Mon, 24 Jun 2019 02:52:56 +0000
Message-ID: <20190624025258.25592-56-e@80x24.org> (raw)
In-Reply-To: <20190624025258.25592-1-e@80x24.org>

At least the subset of epoll we use.  EPOLLET might be
difficult to emulate if we end up using it.
---
 MANIFEST                  |  2 ++
 lib/PublicInbox/DS.pm     | 16 ++++++-----
 lib/PublicInbox/DSPoll.pm | 58 +++++++++++++++++++++++++++++++++++++++
 t/ds-poll.t               | 58 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 127 insertions(+), 7 deletions(-)
 create mode 100644 lib/PublicInbox/DSPoll.pm
 create mode 100644 t/ds-poll.t

diff --git a/MANIFEST b/MANIFEST
index 52c4790e..29920953 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -78,6 +78,7 @@ lib/PublicInbox/Config.pm
 lib/PublicInbox/ContentId.pm
 lib/PublicInbox/DS.pm
 lib/PublicInbox/DSKQXS.pm
+lib/PublicInbox/DSPoll.pm
 lib/PublicInbox/Daemon.pm
 lib/PublicInbox/Emergency.pm
 lib/PublicInbox/EvCleanup.pm
@@ -191,6 +192,7 @@ t/content_id.t
 t/convert-compact.t
 t/data/0001.patch
 t/ds-leak.t
+t/ds-poll.t
 t/edit.t
 t/emergency.t
 t/fail-bin/spamc
diff --git a/lib/PublicInbox/DS.pm b/lib/PublicInbox/DS.pm
index d6ef0b8d..e3479e66 100644
--- a/lib/PublicInbox/DS.pm
+++ b/lib/PublicInbox/DS.pm
@@ -142,15 +142,17 @@ sub _InitPoller
     return if $DoneInit;
     $DoneInit = 1;
 
-    if (!PublicInbox::Syscall::epoll_defined())  {
-        $Epoll = eval {
-            require PublicInbox::DSKQXS;
-            PublicInbox::DSKQXS->import;
-            PublicInbox::DSKQXS->new;
-        };
-    } else {
+    if (PublicInbox::Syscall::epoll_defined())  {
         $Epoll = epoll_create();
         set_cloexec($Epoll) if (defined($Epoll) && $Epoll >= 0);
+    } else {
+        my $cls;
+        for (qw(DSKQXS DSPoll)) {
+            $cls = "PublicInbox::$_";
+            last if eval "require $cls";
+        }
+        $cls->import;
+        $Epoll = $cls->new;
     }
     *EventLoop = *EpollEventLoop;
 }
diff --git a/lib/PublicInbox/DSPoll.pm b/lib/PublicInbox/DSPoll.pm
new file mode 100644
index 00000000..e65640a8
--- /dev/null
+++ b/lib/PublicInbox/DSPoll.pm
@@ -0,0 +1,58 @@
+# Copyright (C) 2019 all contributors <meta@public-inbox.org>
+# Licensed the same as Danga::Socket (and Perl5)
+# License: GPL-1.0+ or Artistic-1.0-Perl
+#  <https://www.gnu.org/licenses/gpl-1.0.txt>
+#  <https://dev.perl.org/licenses/artistic.html>
+#
+# poll(2) via IO::Poll core module.  This makes poll look
+# like epoll to simplify the code in DS.pm.  This is NOT meant to be
+# an all encompassing emulation of epoll via IO::Poll, but just to
+# support cases public-inbox-nntpd/httpd care about.
+package PublicInbox::DSPoll;
+use strict;
+use warnings;
+use parent qw(Exporter);
+use IO::Poll;
+use PublicInbox::Syscall qw(EPOLLONESHOT EPOLLIN EPOLLOUT EPOLL_CTL_DEL);
+our @EXPORT = qw(epoll_ctl epoll_wait);
+
+sub new { bless {}, $_[0] } # fd => events
+
+sub epoll_ctl {
+	my ($self, $op, $fd, $ev) = @_;
+
+	# not wasting time on error checking
+	if ($op != EPOLL_CTL_DEL) {
+		$self->{$fd} = $ev;
+	} else {
+		delete $self->{$fd};
+	}
+	0;
+}
+
+sub epoll_wait {
+	my ($self, $maxevents, $timeout_msec, $events) = @_;
+	my @pset;
+	while (my ($fd, $events) = each %$self) {
+		my $pevents = $events & EPOLLIN ? POLLIN : 0;
+		$pevents |= $events & EPOLLOUT ? POLLOUT : 0;
+		push(@pset, $fd, $pevents);
+	}
+	@$events = ();
+	my $n = IO::Poll::_poll($timeout_msec, @pset);
+	if ($n >= 0) {
+		for (my $i = 0; $i < @pset; ) {
+			my $fd = $pset[$i++];
+			my $revents = $pset[$i++] or next;
+			delete($self->{$fd}) if $self->{$fd} & EPOLLONESHOT;
+			push @$events, [ $fd ];
+		}
+		my $nevents = scalar @$events;
+		if ($n != $nevents) {
+			warn "BUG? poll() returned $n, but got $nevents";
+		}
+	}
+	$n;
+}
+
+1;
diff --git a/t/ds-poll.t b/t/ds-poll.t
new file mode 100644
index 00000000..a397ee06
--- /dev/null
+++ b/t/ds-poll.t
@@ -0,0 +1,58 @@
+# Copyright (C) 2019 all contributors <meta@public-inbox.org>
+# Licensed the same as Danga::Socket (and Perl5)
+# License: GPL-1.0+ or Artistic-1.0-Perl
+#  <https://www.gnu.org/licenses/gpl-1.0.txt>
+#  <https://dev.perl.org/licenses/artistic.html>
+use strict;
+use warnings;
+use Test::More;
+use PublicInbox::Syscall qw(:epoll);
+my $cls = 'PublicInbox::DSPoll';
+use_ok $cls;
+my $p = $cls->new;
+
+my ($r, $w, $x, $y);
+pipe($r, $w) or die;
+pipe($x, $y) or die;
+is(epoll_ctl($p, EPOLL_CTL_ADD, fileno($r), EPOLLIN), 0, 'add EPOLLIN');
+my $events = [];
+my $n = epoll_wait($p, 9, 0, $events);
+is_deeply($events, [], 'no events set');
+is($n, 0, 'nothing ready, yet');
+is(epoll_ctl($p, EPOLL_CTL_ADD, fileno($w), EPOLLOUT|EPOLLONESHOT), 0,
+	'add EPOLLOUT|EPOLLONESHOT');
+$n = epoll_wait($p, 9, -1, $events);
+is($n, 1, 'got POLLOUT event');
+is($events->[0]->[0], fileno($w), '$w ready');
+
+$n = epoll_wait($p, 9, 0, $events);
+is($n, 0, 'nothing ready after oneshot');
+is_deeply($events, [], 'no events set after oneshot');
+
+syswrite($w, '1') == 1 or die;
+for my $t (0..1) {
+	$n = epoll_wait($p, 9, $t, $events);
+	is($events->[0]->[0], fileno($r), "level-trigger POLLIN ready #$t");
+	is($n, 1, "only event ready #$t");
+}
+syswrite($y, '1') == 1 or die;
+is(epoll_ctl($p, EPOLL_CTL_ADD, fileno($x), EPOLLIN|EPOLLONESHOT), 0,
+	'EPOLLIN|EPOLLONESHOT add');
+is(epoll_wait($p, 9, -1, $events), 2, 'epoll_wait has 2 ready');
+my @fds = sort(map { $_->[0] } @$events);
+my @exp = sort((fileno($r), fileno($x)));
+is_deeply(\@fds, \@exp, 'got both ready FDs');
+
+# EPOLL_CTL_DEL doesn't matter for kqueue, we do it in native epoll
+# to avoid a kernel-wide lock; but its not needed for native kqueue
+# paths so DSKQXS makes it a noop (as did Danga::Socket::close).
+SKIP: {
+	if ($cls ne 'PublicInbox::DSPoll') {
+		skip "$cls doesn't handle EPOLL_CTL_DEL", 2;
+	}
+	is(epoll_ctl($p, EPOLL_CTL_DEL, fileno($r), 0), 0, 'EPOLL_CTL_DEL OK');
+	$n = epoll_wait($p, 9, 0, $events);
+	is($n, 0, 'nothing ready after EPOLL_CTL_DEL');
+};
+
+done_testing;
-- 
EW


  parent reply index

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-24  2:52 [PATCH 00/57] ds: shrink, TLS support, buffer writes to FS Eric Wong
2019-06-24  2:52 ` [PATCH 01/57] ds: get rid of {closed} field Eric Wong
2019-06-24  2:52 ` [PATCH 02/57] ds: get rid of more unused debug instance methods Eric Wong
2019-06-24  2:52 ` [PATCH 03/57] ds: use and export monotonic now() Eric Wong
2019-06-24  2:52 ` [PATCH 04/57] AddTimer: avoid clock_gettime for the '0' case Eric Wong
2019-06-24  2:52 ` [PATCH 05/57] ds: get rid of on_incomplete_write wrapper Eric Wong
2019-06-24  2:52 ` [PATCH 06/57] ds: lazy initialize wbuf_off Eric Wong
2019-06-24  2:52 ` [PATCH 07/57] ds: split out from ->flush_write and ->write Eric Wong
2019-06-24  2:52 ` [PATCH 08/57] ds: lazy-initialize wbuf Eric Wong
2019-06-24  2:52 ` [PATCH 09/57] ds: don't pass `events' arg to EPOLL_CTL_DEL Eric Wong
2019-06-24  2:52 ` [PATCH 10/57] ds: remove support for DS->write(undef) Eric Wong
2019-06-24  2:52 ` [PATCH 11/57] http: favor DS->write(strref) when reasonable Eric Wong
2019-06-24  2:52 ` [PATCH 12/57] ds: share send(..., MSG_MORE) logic Eric Wong
2019-06-24  2:52 ` [PATCH 13/57] ds: switch write buffering to use a tempfile Eric Wong
2019-06-24  2:52 ` [PATCH 14/57] ds: get rid of redundant and unnecessary POLL* constants Eric Wong
2019-06-24  2:52 ` [PATCH 15/57] syscall: get rid of unused EPOLL* constants Eric Wong
2019-06-24  2:52 ` [PATCH 16/57] syscall: get rid of unnecessary uname local vars Eric Wong
2019-06-24  2:52 ` [PATCH 17/57] ds: set event flags directly at initialization Eric Wong
2019-06-24  2:52 ` [PATCH 18/57] ds: import IO::KQueue namespace Eric Wong
2019-06-24  2:52 ` [PATCH 19/57] ds: share watch_chg between watch_read/watch_write Eric Wong
2019-06-24  2:52 ` [PATCH 20/57] ds: remove IO::Poll support (for now) Eric Wong
2019-06-24  2:52 ` [PATCH 21/57] ds: get rid of event_watch field Eric Wong
2019-06-24  2:52 ` [PATCH 22/57] httpd/async: remove EINTR check Eric Wong
2019-06-24  2:52 ` [PATCH 23/57] spawn: remove `Blocking' flag handling Eric Wong
2019-06-24  2:52 ` [PATCH 24/57] qspawn: describe where `$rpipe' come from Eric Wong
2019-06-24  2:52 ` [PATCH 25/57] http|nntp: favor "$! == EFOO" over $!{EFOO} checks Eric Wong
2019-06-24  2:52 ` [PATCH 26/57] ds: favor `delete' over assigning fields to `undef' Eric Wong
2019-06-24  2:52 ` [PATCH 27/57] http: don't pass extra args to PublicInbox::DS::close Eric Wong
2019-06-24  2:52 ` [PATCH 28/57] ds: pass $self to code references Eric Wong
2019-06-24  2:52 ` [PATCH 29/57] evcleanup: replace _run_asap with `event_step' callback Eric Wong
2019-06-24  2:52 ` [PATCH 30/57] ds: remove pointless exit calls Eric Wong
2019-06-24  2:52 ` [PATCH 31/57] http|nntp: be explicit about bytes::length on rbuf Eric Wong
2019-06-24  2:52 ` [PATCH 32/57] ds: hoist out do_read from NNTP and HTTP Eric Wong
2019-06-24  2:52 ` [PATCH 33/57] nntp: simplify re-arming/requeue logic Eric Wong
2019-06-24  2:52 ` [PATCH 34/57] allow use of PerlIO layers for filesystem writes Eric Wong
2019-06-24  2:52 ` [PATCH 35/57] ds: deal better with FS-related errors IO buffers Eric Wong
2019-06-24  2:52 ` [PATCH 36/57] nntp: wait for writability before sending greeting Eric Wong
2019-06-24  2:52 ` [PATCH 37/57] nntp: NNTPS and NNTP+STARTTLS working Eric Wong
2019-06-24  2:52 ` [PATCH 38/57] certs/create-certs.perl: fix cert validity on 32-bit Eric Wong
2019-06-24  2:52 ` [PATCH 39/57] daemon: map inherited sockets to well-known schemes Eric Wong
2019-06-24  2:52 ` [PATCH 40/57] ds|nntp: use CORE::close on socket Eric Wong
2019-06-24  2:52 ` [PATCH 41/57] nntp: call SSL_shutdown in normal cases Eric Wong
2019-06-24  2:52 ` [PATCH 42/57] t/nntpd-tls: slow client connection test Eric Wong
2019-06-24  2:52 ` [PATCH 43/57] daemon: use SSL_MODE_RELEASE_BUFFERS Eric Wong
2019-06-24  2:52 ` [PATCH 44/57] ds: allow ->write callbacks to syswrite directly Eric Wong
2019-06-24  2:52 ` [PATCH 45/57] nntp: reduce allocations for greeting Eric Wong
2019-06-24  2:52 ` [PATCH 46/57] ds: always use EV_ADD with EV_SET Eric Wong
2019-06-24  2:52 ` [PATCH 47/57] nntp: simplify long response logic and fix nesting Eric Wong
2019-06-24  2:52 ` [PATCH 48/57] ds: flush_write runs ->write callbacks even if closed Eric Wong
2019-06-24  2:52 ` [PATCH 49/57] nntp: lazily allocate and stash rbuf Eric Wong
2019-06-24  2:52 ` [PATCH 50/57] ci: require IO::KQueue on FreeBSD, for now Eric Wong
2019-06-24  2:52 ` [PATCH 51/57] nntp: send greeting immediately for plain sockets Eric Wong
2019-06-24  2:52 ` [PATCH 52/57] daemon: set TCP_DEFER_ACCEPT on everything but NNTP Eric Wong
2019-06-24  2:52 ` [PATCH 53/57] daemon: use FreeBSD accept filters on non-NNTP Eric Wong
2019-06-24  2:52 ` [PATCH 54/57] ds: split out IO::KQueue-specific code Eric Wong
2019-06-24  5:24   ` Eric Wong
2019-06-24  2:52 ` Eric Wong [this message]
2019-06-24  2:52 ` [PATCH 56/57] Revert "ci: require IO::KQueue on FreeBSD, for now" Eric Wong
2019-06-24  2:52 ` [PATCH 57/57] ds: reduce overhead of tempfile creation Eric Wong
2019-06-24  5:25 ` [PATCH 58/57] Makefile: skip DSKQXS in global syntax check Eric Wong
2019-06-24 18:28 ` [PATCH 59/57] ds: ->write must not clobber empty wbuf array Eric Wong

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