Eric Wong [Tue, 1 Oct 2019 01:03:55 +0000 (01:03 +0000)]
TODO: update with "git cat-file" items
Millions of inboxes in an instance is probably not feasible, but
dozens or even hundreds could happen and
/proc/sys/fs/pipe-user-pages-soft is only 16384 on my system,
with each "cat-file --batch" process using 16+1 pages worth
of pipes.
The httpd-supplied write callback is the leak culprit under Perl
5.16.3. undef-ing it immediately after use keeps a repeated
"git fetch" loop from monotonically increasing memory and FD use
on the Perl shipped with RHEL/CentOS 7.x.
Other endpoints tested showed no increase in memory use under
constant load with "ab -HAccept-Encoding:gzip -k", including the
async psgi_qx code path used by $INBOX_URL/$OBJECT_ID/s/ via
SolverGit module.
Eric Wong [Fri, 27 Sep 2019 10:48:25 +0000 (10:48 +0000)]
wwwtext: support $INBOX_URL/_/text/config/raw
This returns a git-config(1)-compatible file to make it easier
to get started on mirroring an existing public-inbox. Omitting
the "raw" from the URL works, as well, but I'm not sure if
it's very useful.
Alyssa Ross [Tue, 24 Sep 2019 20:05:55 +0000 (20:05 +0000)]
hlmod: update for highlight 3.51 API change
Quoting Amitai Schleier, who made this same change in ikiwiki[1],
where lots of the public-inbox highlight code comes from:
> As of 3.51, searchFile() is no longer provided in highlight's Perl
> bindings (at least on NetBSD and OS X, as built from pkgsrc). This
> leaves us falling through to getConfDir(), which has been gone
> rather longer.
>
> From highlight git, it appears searchFile() and getFiletypesConfPath()
> both originated in the 3.14 release. The latter is still available in
> 3.51, and returns the same result searchFile() used to. Switch to it.
So, this should still be compatible with the version of highlight.pm in
Debian, but add support for newer versions as well.
Eric Wong [Thu, 26 Sep 2019 01:50:38 +0000 (01:50 +0000)]
httpd: disable Deflater middleware by default on Perl <5.18
Testing with perl-5.16.3-294.el7_6 RPM package on RHEL/CentOS 7,
the Deflater middleware triggers a leak when used in conjunction
with our push-based responses from PublicInbox::Qspawn.
I could not find another solution to workaround the memory leak
in this case, and I could not find a specific leak fix in
the perl5180delta manpage[1] which looked like it would
solve our problem.
Attempting to workaround the issue proved futile. Using
internal Deflater-specific keys to prevent deflating in
GitHTTPBackend and Qspawn did not solve the problem:
So this appears to be a problem with Plack::Util::response_cb
somewhere.
This does NOT appear to be a problem with ref() leaking as in
DS::next_tick[2], since I couldn't find where
Plack::Middleware::Deflater or Plack::Util::response_cb would be
calling ref() on a blessed reference to trigger a leak.
Also, oddly enough, the ref() use for backwards compatibility at
the top of PublicInbox::GitHTTPBackend::serve does NOT seem to
trigger a leak on 5.16.3 due to [2]:
# XXX compatibility... ugh, can we stop supporting this?
$git = PublicInbox::Git->new($git) unless ref($git);
Eric Wong [Thu, 26 Sep 2019 01:50:37 +0000 (01:50 +0000)]
ds: workaround a memory leak in Perl 5.16.x
The perl-5.16.3-294.el7_6 RPM package on RHEL/CentOS 7 is
affected by a memory leak in Perl when calling `ref' on
blessed references. This resulted in a very slow leak that
manifests more quickly with a nonstop "git fetch" loop.
Use Scalar::Util::blessed to work around the issue.
Tested overnight on a CentOS 7 VM.
Eric Wong [Tue, 24 Sep 2019 03:39:03 +0000 (03:39 +0000)]
spawnpp: use absolute path for exec
We support "-env" to clear the environment with spawn(),
which causes test failures but no runtime failures
(since "-env" isn't used anywhere in our real code)
Reported-and-tested-by: Alyssa Ross <hi@alyssa.is>
Eric Wong [Sat, 21 Sep 2019 00:06:42 +0000 (00:06 +0000)]
doc: update HACKING and TODO with a few items
Inline::C seems alright, so we might use it more since it still
allows end users to quickly make changes. Our performance on
rotational disks is also terrible, and could be improved...
Eric Wong [Fri, 20 Sep 2019 02:42:14 +0000 (02:42 +0000)]
wwwatomstream: fix per-feed <id>
We were emitting the same "<id>mailto:name@domain</id>" tag
for every feed (but not per-feed entry). This could cause
feed readers to mistake the top (news.atom) feed for other
feeds (search results, or per-thread feeds).
This is technically a breaking change for people relying on
per-thread or per-query feeds, but the only alternative is
to remain broken for anybody trying to follow multiple feeds
off the same inbox.
Eric Wong [Wed, 18 Sep 2019 19:50:50 +0000 (19:50 +0000)]
config: boolean handling matches git-config(1)
We need to handle arbitrary integers and case-insensitive
variations of human words to match git-config(1) behavior,
since that's what users would expect given we use config
files parseable by git-config(1).
Eric Wong [Sat, 14 Sep 2019 19:50:34 +0000 (19:50 +0000)]
doc: add release notes directory
The v1.2.0 is a work-in-progress, while the others are copied
out of our mail archives.
Eventually, a NEWS file will be generated from these emails and
distributed in the release tarball. There'll also be an Atom
feed for the website reusing our feed generation code.
Eric Wong [Tue, 17 Sep 2019 08:31:23 +0000 (08:31 +0000)]
http: remove unnecessary delete
Only removing $http->{env} is needed to prevent circular
references. $env->{'psgix.io'} does not need to be deleted
since $env will no longer have any references to it when
->close returns.
Eric Wong [Tue, 17 Sep 2019 08:31:20 +0000 (08:31 +0000)]
qspawn: shorten lifetime of circular references
All of these circular references are designed to clear
themselves, but these will make actual errors from Devel::Cycle
easier-to-spot.
The circular reference in the limiter {run_queue} is not a real
problem, but we can avoid storing the circular reference until
we actually need to spawn the child, reducing the size of the
Qspawn object while it's in the queue, slightly.
We also do not need to have redundant checks to spawn new
processes, we should only spawn new processes when they're
->start-ed or after waitpid reaps them.
Eric Wong [Tue, 17 Sep 2019 08:31:18 +0000 (08:31 +0000)]
qspawn: remove return value from ->finish
We don't use the return value in real code since we do waitpid
asynchronously, now. So simplify our runtime code at the cost
of making our test slighly more complex.
Eric Wong [Sun, 15 Sep 2019 02:25:34 +0000 (02:25 +0000)]
qspawn: shorten lifetime of environ and opts args
We don't need to hold onto the subprocess environ and
redirects/options for popen_rd after spawning the child process.
I do not expect this to fix problem of leaking unlinked regular
file descriptors (which I still can't reproduce), and it
definitely does not fix the problem of leaking pipe descriptors
(which I also can't reproduce).
This will save an FD sooner on non-public-inbox-httpd servers
which give a non-FD $env->{'psgi.input'}, however
Regardless, it's good to free up memory resources in our own
process ASAP we're done using them.
Eric Wong [Sun, 15 Sep 2019 01:00:06 +0000 (01:00 +0000)]
qspawn: clarify and improve error handling
EINTR should not happen when using non-blocking sockets like we
do in our daemons, but maybe some OSes allow it to happen and
edge-triggered notifications won't notify us again.
So always retry immediately on EINTR without relying on kqueue
or epoll to notify us, and log any other unrecoverable errors
which may happen while we're at it.
Eric Wong [Sat, 14 Sep 2019 18:28:54 +0000 (18:28 +0000)]
doc: update nntpd with NNTPS and STARTTLS examples
NNTPS and STARTTLS seems to be working for several months
without incident on news.public-inbox.org, so consider it a
success and maybe others can try using it.
HTTPS technically works, too, but isn't documented at
the moment since I can't recommend production deployments
without varnish protecting it.
Eric Wong [Thu, 12 Sep 2019 23:16:52 +0000 (23:16 +0000)]
githttpbackend: use REMOTE_ADDR for deleted identifier
REMOTE_HOST is not set by us (it is the reverse DNS name) of
REMOTE_ADDR, and there's few better ways to kill HTTP server
performance than to use standard name resolution APIs like
getnameinfo(3).
Eric Wong [Thu, 12 Sep 2019 08:34:20 +0000 (08:34 +0000)]
tmpfile: give temporary files meaningful names
Although we always unlink temporary files, give them a
meaningful name so that we can we can still make sense
of the pre-unlink name when using lsof(8) or similar
tools on Linux.
Eric Wong [Sat, 14 Sep 2019 09:21:14 +0000 (09:21 +0000)]
qspawn: simplify by using PerlIO::scalar
I didn't know PerlIO::scalar existed until a few months ago,
but it's been distributed with Perl since 5.8 and doesn't
seem to be split out into it's own package on any distro.
Eric Wong [Thu, 12 Sep 2019 06:54:28 +0000 (06:54 +0000)]
solvergit: don't drop update-index stdin with qspawn
It's possible for Qspawn callers to be deferred, in which case
we must ensure we don't cause the temporary file used for
stdin to become unref-ed and closed.
This can be a problem when we exceed the default Qspawn
limiter of 32 concurrent processes for "git update-index".
Eric Wong [Sun, 8 Sep 2019 10:41:12 +0000 (10:41 +0000)]
nntp: regexp always consumes rbuf if "\n" exists
We don't want to get hung into a state where we see "\n" via
index(), yet cannot consume rbuf in the while loop. So tweak
the regexp to ensure we always consume rbuf.
I suspect this is what causes occasional 100% CPU usage of
-nntpd, but reproducing it's been difficult..
Eric Wong [Sun, 14 Jul 2019 02:56:36 +0000 (02:56 +0000)]
nntpdeflate: reduce overhead of idle clients
We don't need to keep an empty buffer around in the common case
when a client is sending us completely inflatable requests and
we're able to read them in one go.
This only seems to save about 2M with 10K NNTPS clients using
COMPRESS, so it's not a huge win, but better than nothing.
Eric Wong [Sat, 13 Jul 2019 21:38:11 +0000 (21:38 +0000)]
nntp: fix LIST OVERVIEW.FMT ordering and format
RFC3977 8.4.2 mandates the order of non-standard headers
to be after the first seven standard headers/metadata;
so "Xref:" must appear after "Lines:"|":lines".
Additionally, non-required header names must be followed
by ":full".
Cc: Jonathan Corbet <corbet@lwn.net> Reported-by: Urs Janßen
<E1hmKBw-0008Bq-8t@akw>
Eric Wong [Sat, 13 Jul 2019 20:27:57 +0000 (20:27 +0000)]
nntpdeflate: stop relying on SUPER for ->do_read
We won't need further layering after enabling compression. So
be explicit about which sub we're calling when we hit ->do_read
from NNTP and eliminate the need for the comment.
Eric Wong [Wed, 10 Jul 2019 06:13:59 +0000 (06:13 +0000)]
http|nntp: avoid recursion inside ->write
In HTTP.pm, we can use the same technique NNTP.pm uses with
long_response with the $long_cb callback and avoid storing
$pull in the per-client structure at all. We can also reuse
the same logic to push the callback into wbuf from NNTP.
This does NOT introduce a new circular reference, but documents
it more clearly.
Eric Wong [Mon, 8 Jul 2019 07:31:19 +0000 (07:31 +0000)]
http|nntp: "use PublicInbox::DS" instead of ->import
Relying on "use" to import during BEGIN means we get to take
advantage of prototype checking of function args during the rest
of the compilation phase.
* origin/nntp-compress:
nntp: improve error reporting for COMPRESS
nntp: reduce memory overhead of zlib
nntp: support COMPRESS DEFLATE per RFC 8054
nntp: move LINE_MAX constant to the top
nntp: use msg_more as a method
Eric Wong [Mon, 8 Jul 2019 07:01:59 +0000 (07:01 +0000)]
ds: use WNOHANG with waitpid if inside event loop
While we're usually not stuck waiting on waitpid after
seeing a pipe EOF or even triggering SIGPIPE in the process
(e.g. git-http-backend) we're reading from, it MAY happen
and we should be careful to never hang the daemon process
on waitpid calls.
v2: use "eq" for string comparison against 'DEFAULT'
Eric Wong [Sun, 7 Jul 2019 06:57:43 +0000 (06:57 +0000)]
nntp: improve error reporting for COMPRESS
Add some checks for errors at initialization, though there's not
much that can be done with ENOMEM-type errors aside from
dropping clients.
We can also get rid of the scary FIXME for MemLevel=8. It was a
stupid error on my part in the original per-client deflate
stream implementation calling C::R::Z::{Inflate,Deflate} in
array context and getting the extra dualvar error code as a
string result, causing the {zin}/{zout} array refs to have
extra array elements.
Eric Wong [Fri, 5 Jul 2019 22:53:39 +0000 (22:53 +0000)]
nntp: reduce memory overhead of zlib
Using Z_FULL_FLUSH at the right places in our event loop, it
appears we can share a single zlib deflate context across ALL
clients in a process.
The zlib deflate context is the biggest factor in per-client
memory use, so being able to share that across many clients
results in a large memory savings.
With 10K idle-but-did-something NNTP clients connected to a
single process on a 64-bit system, TLS+DEFLATE used around
1.8 GB of RSS before this change. It now uses around 300 MB.
TLS via IO::Socket::SSL alone uses <200MB in the same situation,
so the actual memory reduction is over 10x.
This makes compression less efficient and bandwidth increases
around 45% in informal testing, but it's far better than no
compression at all. It's likely around the same level of
compression gzip gives on the HTTP side.
Security implications with TLS? I don't know, but I don't
really care, either... public-inbox-nntpd doesn't support
authentication and it's up to the client to enable compression.
It's not too different than Varnish caching gzipped responses
on the HTTP side and having responses go to multiple HTTPS
clients.
Eric Wong [Fri, 5 Jul 2019 22:53:36 +0000 (22:53 +0000)]
nntp: use msg_more as a method
It's a tad slower, but we'll be able to subclass this to rely
on zlib deflate buffering. This is advantageous for TLS clients
since (AFAIK) IO::Socket::SSL/OpenSSL doesn't give us ways to use
MSG_MORE or writev(2) like like GNUTLS does.
Eric Wong [Mon, 1 Jul 2019 08:56:51 +0000 (08:56 +0000)]
t/nntpd*.t: require IO::Socket::SSL 2.007 for Net::NNTP tests
Net::NNTP won't attempt to use older versions of IO::Socket::SSL
because 2.007 is the "first version with default CA on most platforms"
according to comments in Net::NNTP. But then again we don't make
remote requests when testing...
Eric Wong [Thu, 4 Jul 2019 10:02:06 +0000 (10:02 +0000)]
qspawn: retry sysread when parsing headers, too
We need to ensure the BIN_DETECT (8000 byte) check in
ViewVCS can be handled properly when sending giant
files. Otherwise, EPOLLET won't notify us, again,
and responses can get stuck.
While we're at it, bump up the read-size up to 4096
bytes so we make fewer trips to the kernel.
Eric Wong [Sun, 30 Jun 2019 01:00:59 +0000 (01:00 +0000)]
nntp: remove DISABLED hash checks
Before I figured out the long_response API, I figured there'd
be expensive, process-monopolizing commands which admins might
want to disable. Nearly 4 years later, we've never needed it
and running a server without commands such as OVER/XOVER is
unimaginable.
Eric Wong [Sun, 30 Jun 2019 22:32:32 +0000 (22:32 +0000)]
t/httpd-unix.t: avoid race in between bind() and listen()
We need to be able to successfully connect() to the socket
before attempting further tests. Merely testing for the
existence of a socket isn't enough, since the server may've
only done bind(), not listen().
Eric Wong [Sun, 30 Jun 2019 22:19:39 +0000 (22:19 +0000)]
daemon: warn on inheriting blocking listeners
For users relying on socket activation via service manager (e.g.
systemd) and running multiple service instances (@1, @2),
we need to ensure configuration of the socket is NonBlocking.
Otherwise, service managers such as systemd may clear the
O_NONBLOCK flag for a small window where accept/accept4
blocks:
Eric Wong [Sun, 30 Jun 2019 22:19:38 +0000 (22:19 +0000)]
tests: common tcp_server and unix_server helpers
IO::Socket:*->new options are verbose and we can save
a bunch of code by putting this into t/common.perl,
since the related spawn_listener stuff is already there.
Eric Wong [Sun, 30 Jun 2019 17:13:30 +0000 (17:13 +0000)]
Merge remote-tracking branch 'origin/email-simple-mem' into master
* origin/email-simple-mem:
nntp: reduce syscalls for ARTICLE and BODY
mbox: split header and body processing
mbox: use Email::Simple->new to do in-place modifications
nntp: rework and simplify art_lookup response
Eric Wong [Sun, 30 Jun 2019 07:11:00 +0000 (07:11 +0000)]
examples/*@.service: sockets MUST be NonBlocking
For users running multiple (-nntpd@1, -nntpd@2) instances of
either -httpd or -nntpd via systemd to implement zero-downtime
restarts; it's possible for a listen socket to become blocking
for a moment during an accept syscall and cause a daemons to
get stuck in a blocking accept() during
PublicInbox::Listener::event_step (event_read in previous
versions).
Since O_NONBLOCK is a file description flag, systemd clearing
O_NONBLOCK momentarily (before PublicInbox::Listener::new
re-enables it) creates a window for another instance of our
daemon to get stuck in accept().
Eric Wong [Sun, 30 Jun 2019 03:54:26 +0000 (03:54 +0000)]
ds: rely on refcounting to close descriptors
Since we have EPOLL_CTL_DEL implemented for the poll(2) and
kqueue backends, we can rely on Perl refcounting to gently
close(2) the underlying file descriptors as references get
dropped.
This may be beneficial in the future if we want to drop a
descriptor from the event loop without actually closing it.
Eric Wong [Fri, 28 Jun 2019 19:26:56 +0000 (19:26 +0000)]
http: use bigger, but shorter-lived buffers for pipes
Linux pipes default to 65536 bytes in size, and we want to read
external processes as fast as possible now that we don't use
Danga::Socket or buffer to heap.
However, drop the buffer ASAP if we need to wait on anything;
since idle buffers can be idle for eons. This lets other
execution contexts can reuse that memory right away.
Eric Wong [Fri, 28 Jun 2019 18:58:36 +0000 (18:58 +0000)]
httpd/async: switch to buffering-as-fast-as-possible
With DS buffering to a temporary file nowadays, applying
backpressure to git-http-backend(1) hurts overall memory
usage of the system. Instead, try to get git-http-backend(1)
to finish as quickly as possible and use edge-triggered
notifications to reduce wakeups on our end.
Eric Wong [Fri, 28 Jun 2019 18:55:09 +0000 (18:55 +0000)]
parentpipe: make the ->close call more obvious
We can close directly in event_step without bad side effects,
and then we also don't need to take a reason arg from worker_quit,
since we weren't logging it anywhere.
Eric Wong [Fri, 28 Jun 2019 18:46:10 +0000 (18:46 +0000)]
parentpipe: document and use one-shot wakeups
The master process only dies once and we close ourselves right
away. So it doesn't matter if it's level-triggered or
edge-triggered, actually, but one-shot is most consistent with
our use and keeps the kernel from doing extra work.
Eric Wong [Fri, 28 Jun 2019 05:25:40 +0000 (05:25 +0000)]
ds: handle deferred DS->close after timers
Our hacks in EvCleanup::next_tick and EvCleanup::asap were due
to the fact "closed" sockets were deferred and could not wake
up the event loop, causing certain actions to be delayed until
an event fired.
Instead, ensure we don't sleep if there are pending sockets to
close.
We can then remove most of the EvCleanup stuff
While we're at it, split out immediate timer handling into a
separate array so we don't need to deal with time calculations
for the event loop.
Eric Wong [Wed, 26 Jun 2019 08:11:10 +0000 (08:11 +0000)]
ds: share lazy rbuf handling between HTTP and NNTP
Doing this for HTTP cuts the memory usage of 10K
idle-after-one-request HTTP clients from 92 MB to 47 MB.
The savings over the equivalent NNTP change in commit 6f173864f5acac89769a67739b8c377510711d49,
("nntp: lazily allocate and stash rbuf") seems down to the
size of HTTP requests and the fact HTTP is a client-sends-first
protocol where as NNTP is server-sends-first.
Eric Wong [Sat, 29 Jun 2019 06:34:40 +0000 (06:34 +0000)]
t/ds-leak: fix race
We need to ensure we run lsof on the sleep(1) process, and not
the fork of ourselves before execve(2). This race applies when
we're using the default pure-Perl spawn() implementation.
Eric Wong [Thu, 27 Jun 2019 17:31:30 +0000 (17:31 +0000)]
nntp: reduce syscalls for ARTICLE and BODY
Chances are we already have extra buffer space following the
expensive LF => CRLF conversion that we can safely append an
extra CRLF in those places without incurring a copy of the
full string buffer.
While we're at it, document where our pain points are in terms
of memory usage, since tracking/controlling memory use isn't
exactly obvious in high-level languages.
Perhaps we should start storing messages in git as CRLF...
Eric Wong [Thu, 27 Jun 2019 09:23:39 +0000 (09:23 +0000)]
mbox: split header and body processing
When dealing with ~30MB messages, we can save another ~30MB by
splitting the header and body processing and not appending the
body string back to the header.
We'll rely on buffering in gzip or kernel (via MSG_MORE)
to prevent silly packet sizes.
Eric Wong [Thu, 27 Jun 2019 08:40:19 +0000 (08:40 +0000)]
mbox: use Email::Simple->new to do in-place modifications
Email::Simple->new will split the head from the body in-place,
and we can avoid using Email::Simple::body. This saves us from
holding an extra copy of the message in memory, and saves us
around ~30MB when operating on ~30MB messages.
Eric Wong [Thu, 27 Jun 2019 04:11:22 +0000 (04:11 +0000)]
nntp: rework and simplify art_lookup response
We don't need some of the array elements returned from
art_lookup, anymore (and haven't used them in years).
We can also shorten the lifetime of the Email::Simple object by
relying on the fact Email::Simple->new will modify it's arg if
given a SCALARREF and allow us to avoid Email::Simple::body
calls.
Unfortunately, this doesn't seem to provide any noticeable
improvement in memory usage when dealing with a 30+ MB test
message, since our previous use of ->body_set('') was saving
some memory, but forcing a LF-only body to be CRLF was making
Perl allocate extra space for s///sg.
Eric Wong [Mon, 24 Jun 2019 08:16:43 +0000 (08:16 +0000)]
certs/create-certs: create certs in 'certs/' directory
If running in our top-level source tree, use the 'certs/'
directory as the prefix so we can just invoke `./certs/create-certs.perl'
instead of `(cd certs && ./create-certs.perl)'
Eric Wong [Wed, 26 Jun 2019 07:58:15 +0000 (07:58 +0000)]
ds: cleanup poll test and avoid clobbering imports
On Linux systems with epoll support, we don't want to be
clobbering defined subs in the t/ds-poll.t test; so use
OO ->method dispatch instead and require users to explicitly
import subs via EXPORT_OK.