* Re: [PATCH 10/17] daemon: avoid race when quitting workers
2019-11-24 0:22 6% ` [PATCH 10/17] daemon: avoid race when quitting workers Eric Wong
@ 2019-11-25 8:59 7% ` Eric Wong
0 siblings, 0 replies; 3+ results
From: Eric Wong @ 2019-11-25 8:59 UTC (permalink / raw)
To: meta
Eric Wong <e@80x24.org> wrote:
> While the master process has a self-pipe to avoid missing
> signals, worker processes lack that aside from a pipe to
> detect master death.
>
> That pipe doesn't exist when there's no master process,
> so it's possible DS::close never finishes because it
> never woke up from epoll_wait. So create a pipe on
> the worker_quit signal and force it into epoll/kevent
> so it wakes up right away.
Nope. A self-pipe in any pure-Perl form is insufficient,
since Perl_csighandler() can't wake up processes from any
sleeping syscalls (no-internal self-pipe/eventfd like
other VMs).
Fortunately, Perl exposes sigprocmask, so signalfd should be
usable on Linux. EVFILT_SIGNAL also exists for kevent...
IO::Poll users might be out-of-luck (anybody try GNU/Hurd?)
^ permalink raw reply [relevance 7%]
* [PATCH 10/17] daemon: avoid race when quitting workers
2019-11-24 0:22 6% ` [PATCH 00/17] test fixes and cleanups Eric Wong
@ 2019-11-24 0:22 6% ` Eric Wong
2019-11-25 8:59 7% ` Eric Wong
0 siblings, 1 reply; 3+ results
From: Eric Wong @ 2019-11-24 0:22 UTC (permalink / raw)
To: meta
While the master process has a self-pipe to avoid missing
signals, worker processes lack that aside from a pipe to
detect master death.
That pipe doesn't exist when there's no master process,
so it's possible DS::close never finishes because it
never woke up from epoll_wait. So create a pipe on
the worker_quit signal and force it into epoll/kevent
so it wakes up right away.
---
lib/PublicInbox/Daemon.pm | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/lib/PublicInbox/Daemon.pm b/lib/PublicInbox/Daemon.pm
index 90f11137..0e3b95d2 100644
--- a/lib/PublicInbox/Daemon.pm
+++ b/lib/PublicInbox/Daemon.pm
@@ -252,6 +252,11 @@ sub daemonize () {
}
}
+sub shrink_pipes {
+ if ($^O eq 'linux') { # 1031: F_SETPIPE_SZ, 4096: page size
+ fcntl($_, 1031, 4096) for @_;
+ }
+}
sub worker_quit {
# killing again terminates immediately:
@@ -260,6 +265,17 @@ sub worker_quit {
$_->close foreach @listeners; # call PublicInbox::DS::close
@listeners = ();
+ # create a lazy self-pipe which kicks us out of the EventLoop
+ # so DS::PostEventLoop can fire
+ if (pipe(my ($r, $w))) {
+ shrink_pipes($w);
+
+ # shrink_pipes == noop
+ PublicInbox::ParentPipe->new($r, *shrink_pipes);
+ close $w; # wake up from the event loop
+ } else {
+ warn "E: pipe failed ($!), quit unreliable\n";
+ }
my $proc_name;
my $warn = 0;
# drop idle connections and try to quit gracefully
@@ -468,10 +484,7 @@ sub unlink_pid_file_safe_ish ($$) {
sub master_loop {
pipe(my ($p0, $p1)) or die "failed to create parent-pipe: $!";
pipe(my ($r, $w)) or die "failed to create self-pipe: $!";
-
- if ($^O eq 'linux') { # 1031: F_SETPIPE_SZ = 1031
- fcntl($_, 1031, 4096) for ($w, $p1);
- }
+ shrink_pipes($w, $p1);
IO::Handle::blocking($w, 0);
my $set_workers = $worker_processes;
^ permalink raw reply related [relevance 6%]
* [PATCH 00/17] test fixes and cleanups
@ 2019-11-24 0:22 6% ` Eric Wong
2019-11-24 0:22 6% ` [PATCH 10/17] daemon: avoid race when quitting workers Eric Wong
0 siblings, 1 reply; 3+ results
From: Eric Wong @ 2019-11-24 0:22 UTC (permalink / raw)
To: meta
There's some fixes for race conditions around daemon
startup and shutdown and resurrects start_script for
slightly improved test performance.
And slowly eliminating all END{} block usages
Eric Wong (17):
tests: disable daemon workers in a few more places
tests: use strict everywhere
t/v1-add-remove-add: quiet down "git init"
t/xcpdb-reshard: test xcpdb --compact
t/httpd-corner: wait for worker process death
t/nntpd-tls: sometimes SSL_connect succeeds quickly
.gitignore: ignore local prove(1) files
daemon: use sigprocmask to block signals at startup
daemon: use sigprocmask when respawning workers
daemon: avoid race when quitting workers
t/common: start_script replaces spawn_listener
t/nntpd-validate: get rid of threads dependency
xapcmd: replace Xtmpdirs with File::Temp->newdir
tests: use File::Temp->newdir instead of tempdir()
tests: quiet down commit graph
t/perf-*.t: use $ENV{GIANT_INBOX_DIR} consistently
tests: move giant inbox/git dependent tests to xt/
.gitignore | 2 +
MANIFEST | 11 ++-
lib/PublicInbox/Daemon.pm | 35 +++++--
lib/PublicInbox/Xapcmd.pm | 73 +++++---------
t/.gitconfig | 4 +
t/admin.t | 4 +-
t/altid.t | 4 +-
t/altid_v2.t | 3 +-
t/cgi.t | 3 +-
t/common.perl | 184 ++++++++++++++++++++++++++---------
t/config.t | 4 +-
t/convert-compact.t | 3 +-
t/edit.t | 3 +-
t/emergency.t | 4 +-
t/feed.t | 3 +-
t/filter_rubylang.t | 5 +-
t/git.t | 6 +-
t/html_index.t | 4 +-
t/httpd-corner.psgi | 2 +-
t/httpd-corner.t | 70 +++++++------
t/httpd-https.t | 31 ++----
t/httpd-unix.t | 51 +++++-----
t/httpd.t | 16 ++-
t/import.t | 4 +-
t/indexlevels-mirror.t | 3 +-
t/init.t | 3 +-
t/mda.t | 3 +-
t/mda_filter_rubylang.t | 3 +-
t/mid.t | 1 +
t/msgmap.t | 4 +-
t/nntpd-tls.t | 42 +++-----
t/nntpd.t | 19 ++--
t/nulsubject.t | 4 +-
t/over.t | 4 +-
t/plack.t | 4 +-
t/psgi_attach.t | 4 +-
t/psgi_bad_mids.t | 4 +-
t/psgi_mount.t | 4 +-
t/psgi_multipart_not.t | 4 +-
t/psgi_scan_all.t | 4 +-
t/psgi_search.t | 4 +-
t/psgi_text.t | 4 +-
t/psgi_v2.t | 3 +-
t/purge.t | 4 +-
t/qspawn.t | 1 +
t/replace.t | 6 +-
t/search-thr-index.t | 4 +-
t/search.t | 4 +-
t/solver_git.t | 3 +-
t/spamcheck_spamc.t | 4 +-
t/v1-add-remove-add.t | 6 +-
t/v1reindex.t | 3 +-
t/v2-add-remove-add.t | 3 +-
t/v2mda.t | 3 +-
t/v2mirror.t | 26 ++---
t/v2reindex.t | 3 +-
t/v2writable.t | 13 ++-
t/watch_filter_rubylang.t | 3 +-
t/watch_maildir.t | 5 +-
t/watch_maildir_v2.t | 10 +-
t/www_listing.t | 11 +--
t/xcpdb-reshard.t | 7 +-
{t => xt}/git-http-backend.t | 19 ++--
{t => xt}/nntpd-validate.t | 57 +++++------
{t => xt}/perf-msgview.t | 6 +-
{t => xt}/perf-nntpd.t | 34 +++----
{t => xt}/perf-threading.t | 8 +-
67 files changed, 462 insertions(+), 431 deletions(-)
create mode 100644 t/.gitconfig
rename {t => xt}/git-http-backend.t (87%)
rename {t => xt}/nntpd-validate.t (85%)
rename {t => xt}/perf-msgview.t (85%)
rename {t => xt}/perf-nntpd.t (79%)
rename {t => xt}/perf-threading.t (72%)
^ permalink raw reply [relevance 6%]
Results 1-3 of 3 | reverse | options above
-- pct% links below jump to the message on this page, permalinks otherwise --
2019-11-16 11:43 [PATCH 29/29] t/common: start_script replaces spawn_listener Eric Wong
2019-11-24 0:22 6% ` [PATCH 00/17] test fixes and cleanups Eric Wong
2019-11-24 0:22 6% ` [PATCH 10/17] daemon: avoid race when quitting workers Eric Wong
2019-11-25 8:59 7% ` Eric Wong
Code repositories for project(s) associated with this public inbox
https://80x24.org/public-inbox.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).