upstream/haproxy
1
0
Fork 0
mirror of https://github.com/haproxy/haproxy.git synced 2026-04-15 21:59:41 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions 3
HAProxy - Load balancer
15325 commits 30 branches 413 tags 227 MiB
C 98.1%
Shell 0.9%
Makefile 0.5%
Lua 0.2%
Python 0.1%
Find a file
Willy Tarreau 87154e3010 BUG/MAJOR: queue: better protect a pendconn being picked from the proxy 
The locking in the dequeuing process was significantly improved by commit
49667c14b ("MEDIUM: queue: take the proxy lock only during the px queue
accesses") in that it tries hard to limit the time during which the
proxy's queue lock is held to the strict minimum. Unfortunately it's not
enough anymore, because we take up the task and manipulate a few pendconn
elements after releasing the proxy's lock (while we're under the server's
lock) but the task will not necessarily hold the server lock since it may
not have successfully found one (e.g. timeout in the backend queue). As
such, stream_free() calling pendconn_free() may release the pendconn
immediately after the proxy's lock is released while the other thread
currently proceeding with the dequeuing tries to wake up the owner's
task and dies in task_wakeup().

One solution consists in releasing le proxy's lock later. But tests have
shown that we'd have to sacrifice a significant share of the performance
gained with the patch above (roughly a 20% loss).

This patch takes another approach. It adds a "del_lock" to each pendconn
struct, that allows to keep it referenced while the proxy's lock is being
released. It's mostly a serialization lock like a refcount, just to maintain
the pendconn alive till the task_wakeup() call is complete. This way we can
continue to release the proxy's lock early while keeping this one. It had
to be added to the few points where we're about to free a pendconn, namely
in pendconn_dequeue() and pendconn_unlink(). This way we continue to
release the proxy's lock very early and there is no performance degradation.

This lock may only be held under the queue's lock to prevent lock
inversion.

No backport is needed since the patch above was merged in 2.5-dev only.
2021-08-31 18:37:13 +02:00
.github MEDIUM: config: Deprecate tune.ssl.capture-cipherlist-size 2021-08-26 19:52:04 +02:00
addons BUILD: opentracing: fixed build when using pkg-config utility 2021-08-01 18:18:29 +02:00
admin MINOR: systemd: remove the ExecStartPre line in the unit file 2021-08-20 23:36:45 +02:00
dev CLEANUP: dev/flags: remove useless test in the stdin number parser 2021-04-03 15:29:10 +02:00
doc MINOR: log: Add new "error-log-format" option 2021-08-31 12:13:08 +02:00
examples MEDIUM: proxy: remove long-broken 'option http_proxy' 2021-07-18 19:35:32 +02:00
include BUG/MAJOR: queue: better protect a pendconn being picked from the proxy 2021-08-31 18:37:13 +02:00
reg-tests MINOR: log: Add new "error-log-format" option 2021-08-31 12:13:08 +02:00
scripts BUILD: adopt script/build-ssl.sh for OpenSSL-3.0.0beta2 2021-08-25 05:16:00 +02:00
src BUG/MAJOR: queue: better protect a pendconn being picked from the proxy 2021-08-31 18:37:13 +02:00
tests CLEANUP: assorted typo fixes in the code and comments 2021-08-16 12:37:59 +02:00
.cirrus.yml CI: introduce scripts/build-vtest.sh for installing VTest 2021-05-18 10:48:30 +02:00
.gitattributes MINOR: Configure the cpp userdiff driver for *.[ch] in .gitattributes 2021-02-22 18:17:57 +01:00
.gitignore DOC: lua-api: Add documentation about lua filters 2021-08-15 20:56:44 +02:00
.travis.yml CI: travis-ci: temporarily disable arm64 builds 2021-08-07 07:28:15 +02:00
BRANCHES DOC: fix some spelling issues over multiple files 2021-01-08 14:53:47 +01:00
CHANGELOG [RELEASE] Released version 2.5-dev5 2021-08-28 13:46:11 +02:00
CONTRIBUTING CLEANUP: assorted typo fixes in the code and comments 2021-08-16 12:37:59 +02:00
INSTALL CLEANUP: assorted typo fixes in the code and comments 2021-08-16 12:37:59 +02:00
LICENSE LICENSE: add licence exception for OpenSSL 2012-09-07 13:52:26 +02:00
MAINTAINERS CONTRIB: move spoa_example out of the tree 2021-04-21 09:39:06 +02:00
Makefile BUILD: globally enable -Wundef 2021-08-30 10:16:30 +02:00
README DOC: create a BRANCHES file to explain the life cycle 2019-06-15 22:00:14 +02:00
ROADMAP DOC: update the outdated ROADMAP file 2019-06-15 21:59:54 +02:00
SUBVERS BUILD: use format tags in VERDATE and SUBVERS files 2013-12-10 11:22:49 +01:00
VERDATE [RELEASE] Released version 2.5-dev5 2021-08-28 13:46:11 +02:00
VERSION [RELEASE] Released version 2.5-dev5 2021-08-28 13:46:11 +02:00

README 

The HAProxy documentation has been split into a number of different files for
ease of use.

Please refer to the following files depending on what you're looking for :

  - INSTALL for instructions on how to build and install HAProxy
  - BRANCHES to understand the project's life cycle and what version to use
  - LICENSE for the project's license
  - CONTRIBUTING for the process to follow to submit contributions

The more detailed documentation is located into the doc/ directory :

  - doc/intro.txt for a quick introduction on HAProxy
  - doc/configuration.txt for the configuration's reference manual
  - doc/lua.txt for the Lua's reference manual
  - doc/SPOE.txt for how to use the SPOE engine
  - doc/network-namespaces.txt for how to use network namespaces under Linux
  - doc/management.txt for the management guide
  - doc/regression-testing.txt for how to use the regression testing suite
  - doc/peers.txt for the peers protocol reference
  - doc/coding-style.txt for how to adopt HAProxy's coding style
  - doc/internals for developer-specific documentation (not all up to date)