These are some leftovers from the ancient code where they were still
called sessions, but these areas in the code remain confusing due to
this naming. They were now called "strm" which will not even affect
indenting nor alignment.
When implementing a client applet, a NULL dereference was encountered on
the error path which increment the counters.
Indeed, the counters incremented are the one in the listener which does
not exist in the case of client applets, so in sess->listener->counters,
listener is NULL.
This patch fixes the access to the listener structure when accessing
from a sesssion, most of the access are the counters in error paths.
Must be backported as far as 1.8.
The default proxy was passed as a variable to all parsers instead of a
const, which is not without risk, especially when some timeout parsers used
to make some int pointers point to the default values for comparisons. We
want to be certain that none of these parsers will modify the defaults
sections by accident, so it's important to mark this proxy as const.
This patch touches all occurrences found (89).
grq_total was incremented when picking tasks from the global run queue,
but this variable was not defined with threads disabled, and the code
was optimized away at -O2. No backport is needed.
This commit is a fix/complement to the following one :
08d87b3f49
BUG/MEDIUM: backend: never reuse a connection for tcp mode
It fixes the check for the early insertion of backend connections in
the reuse lists if the backend mode is HTTP.
The impact of this bug seems limited because :
- in tcp mode, no insertion is done in the avail list as mux_pt does not
support multiple streams.
- in http mode, muxes are also responsible to insert backend connections
in lists in their detach functions. Prior to this fix the reuse rate
could be slightly inferior.
It can be backported to 2.3.
Currently, there seems to be no way to have the transport layer ready
but not the mux in the function connect_server. Add a BUG_ON to report
if this implicit condition is not true anymore.
This should fix coverity report from github issue #1120.
The actconns list creates massive contention on low server counts because
it's in fact a list of streams using a server, all threads compete on the
list's head and it's still possible to see some watchdog panics on 48
threads under extreme contention with 47 threads trying to add and one
thread trying to delete.
Moving this list per thread is trivial because it's only used by
srv_shutdown_streams(), which simply required to iterate over the list.
The field was renamed to "streams" as it's really a list of streams
rather than a list of connections.
There are multiple per-thread lists in the listeners, which isn't the
most efficient in terms of cache, and doesn't easily allow to store all
the per-thread stuff.
Now we introduce an srv_per_thread structure which the servers will have an
array of, and place the idle/safe/avail conns tree heads into. Overall this
was a fairly mechanical change, and the array is now always initialized for
all servers since we'll put more stuff there. It's worth noting that the Lua
code still has to deal with its own deinit by itself despite being in a
global list, because its server is not dynamically allocated.
Till now servers were only initialized as part of the proxy setup loop,
which doesn't cover peers, tcp log, dns, lua etc. Let's move this part
out of this loop and instead iterate over all registered servers. This
way we're certain to visit them all.
The patch looks big but it's just a move of a large block with the
corresponding reindent (as can be checked with diff -b). It relies
on the two previous ones ("MINOR: server: add a global list of all
known servers and" and "CLEANUP: lua: set a dummy file name and line
number on the dummy servers").
It's a real pain not to have access to the list of all registered servers,
because whenever there is a need to late adjust their configuration, only
those attached to regular proxies are seen, but not the peers, lua, logs
nor DNS.
What this patch does is that new_server() will automatically add the newly
created server to a global list, and it does so as well for the 1 or 2
statically allocated servers created for Lua. This way it will be possible
to iterate over all of them.
The "socket_tcp" and "socket_ssl" servers had no config file name nor
line number, but this is sometimes annoying during debugging or later
in error messages, while all other places using new_server() or
parse_server() make sure to have a valid file:line set. Let's set
something to address this.
Currently the SSL layer checks the validity of its tasklet's context just
in case it would have been stolen, had the connection been idle. Now it
will be able to be notified by the mux when this situation happens so as
not to have to grab the idle connection lock on each pass. This reuses the
TASK_F_USR1 flag just as the muxes do.
These functions are used on the mux layer to indicate that the connection
is becoming idle and that the xprt ought to be careful before checking the
context or that it's not idle anymore and that the context is safe. The
purpose is to allow a mux which is going to release a connection to tell
the xprt to be careful when touching it. At the moment, the xprt are
always careful and that's costly so we want to have the ability to relax
this a bit.
No xprt layer uses this yet.
The muxes are touching the idle_conns_lock all the time now because
they need to be careful that no other thread has stolen their tasklet's
context.
This patch changes this a little bit by setting the TASK_F_USR1 flag on
the tasklet before marking a connection idle, and removing it once it's
not idle anymore. Thanks to this we have the guarantee that a tasklet
without this flag cannot be present in an idle list and does not need
to go through this costly lock. This is especially true for front
connections.
This flag will be usable by any application. It will be preserved across
wakeups so the application can use it to do various stuff. Some I/O
handlers will soon benefit from this.
It's been too short for quite a while now and is now full. It's still
time to extend it to 32-bits since we have room for this without
wasting any space, so we now gained 16 new bits for future flags.
The values were not reassigned just in case there would be a few
hidden u16 or short somewhere in which these flags are placed (as
it used to be the case with stream->pending_events).
The patch is tagged MEDIUM because this required to update the task's
process() prototype to use an int instead of a short, that's quite a
bunch of places.
It's cleaner to use a flag from the task's state to detect a tasklet
and it's even cheaper. One of the best benefits is that this will
allow to get the nice field out of the common part since the tasklet
doesn't need it anymore. This commit uses the last task bit available
but that's temporary as the purpose of the change is to extend this.
The PRNG used by the "random" LB algorithm was the central one which tries
hard to produce "correct" (i.e. hardly predictable) values suitable for use
in UUIDs or cookies. It's much too expensive for pure load balancing where
a cheaper thread-local PRNG is sufficient, and the current PRNG is part of
the hot places when running with many threads.
Let's switch to the stastistical PRNG instead, it's thread-local, very
fast, and with a period of (2^32)-1 which is more than enough to decide
on a server.
We frequently need to access a simple and fast PRNG for statistical
purposes. The debug_prng() function did exactly this using a xorshift
generator but its use was limited to debug only. Let's move this to
tools.h and tools.c to make it accessible everywhere. Since it needs to
be fast, its state is thread-local. An initialization function starts a
different initial value for each thread for better distribution.
In conn_backend_get() we can cause some extreme contention due to the
idle_conns_lock. Indeed, even though it's per-thread, it still causes
high contention when running with many threads. The reason is that all
threads which do not have any idle connections are quickly skipped,
till the point where there are still some, so the first reaching that
point will grab the lock and the other ones wait behind. From this
point, all threads are synchronized waiting on the same lock, and
will follow the leader in small jumps, all hindering each other.
Here instead of doing this we're using a trylock. This way when a thread
is already checking a list, other ones will continue to next thread. In
the worst case, a high contention will lead to a few new connections to
be set up, but this may actually be what is required to avoid contention
in the first place. With this change, the contention has mostly
disappeared on this lock (it's still present in muxes and transport
layers due to the takeover).
Surprisingly, checking for emptiness of the tree root before taking
the lock didn't address any contention.
A few improvements are still possible and desirable here. The first
one would be to avoid seeing all threads jump to the next one. We
could have each thread use a different prime number as the increment
so as to spread them across the entire table instead of keeping them
synchronized. The second one is that the lock in the muck layers
shouldn't be needed to check for the tasklet's context availability.
Using abort() occasionally results in unexploitable core due to issues
rewinding the stack. Let's use ABORT_NOW() which in addition to crashing
much closer to the call point also has the benefit of showing the call
trace.
We've reached a point where the global pools represent a significant
bottleneck with threads. On a 64-core machine, the performance was
divided by 8 between 32 and 64 H2 connections only because there were
not enough entries in the local caches to avoid picking from the global
pools, and the contention on the list there was very high. It becomes
obvious that we need to have an array of lists, but that will require
more changes.
In parallel, standard memory allocators have improved, with tcmalloc
and jemalloc finding their ways through mainstream systems, and glibc
having upgraded to a thread-aware ptmalloc variant, keeping this level
of contention here isn't justified anymore when we have both the local
per-thread pool caches and a fast process-wide allocator.
For these reasons, this patch introduces a new compile time setting
CONFIG_HAP_NO_GLOBAL_POOLS which is set by default when threads are
enabled with thread local pool caches, and we know we have a fast
thread-aware memory allocator (currently set for glibc>=2.26). In this
case we entirely bypass the global pool and directly use the standard
memory allocator when missing objects from the local pools. It is also
possible to force it at compile time when a good allocator is used with
another setup.
It is still possible to re-enable the global pools using
CONFIG_HAP_GLOBAL_POOLS, if a corner case is discovered regarding the
operating system's default allocator, or when building with a recent
libc but a different allocator which provides other benefits but does
not scale well with threads.
Errors reported by ssl_sock_dump_errors() to stderr would only report the
16 lower bits of the file descriptor because it used to be casted to ushort.
This can be backported to all versions but has really no importance in
practice since this is never seen.
Refactoring performed with the following Coccinelle patch:
@@
char *s;
@@
(
- ist2(s, strlen(s))
+ ist(s)
|
- ist2(strdup(s), strlen(s))
+ ist(strdup(s))
)
Note that this replacement is safe even in the strdup() case, because `ist()`
will not call `strlen()` on a `NULL` pointer. Instead is inserts a length of
`0`, effectively resulting in `IST_NULL`.
When dns_connect_nameserver() is called, the nameserver has always a dgram
field properly defined. The caller, dns_send_nameserver(), already performed
the appropriate verification.
When a DNS session is created, the call to ring_attach() never fails. The
ring is freshly initialized and there is other watcher on it. Thus, the call
always succeeds.
Instead of catching an error that must never happen, we use the DISGUISE()
macro to make static analyzers happy.
Recent changes on the server-state file loading have introduced a
regression. HAproxy crashes if a backend with no server-state file is
disabled in the configuration. Indeed, configuration of such backends is not
finalized. Thus many fields are not defined.
To fix the bug, disabled backends must be ignored. In addition a BUG_ON()
has been added to verify the proxy mode regarding the server-state file. It
must be specified (none, global or local) for enabled backends.
No backport needed.
hlua_pushstrippedstring() function strips leading and trailing LWS
characters. But the result length it too short by 1 byte. Thus the last
non-LWS character is stripped. Note that a string containing only LWS
characters resulting to a stipped string with an invalid length (-1). This
leads to a lua runtime error.
This bug was reported in the issue #1155. It must be backported as far as
1.7.
If dispatch mode or transparent backend is used, the backend connection
target is a proxy instead of a server. In these cases, the reuse of
backend connections is not consistent.
With the default behavior, no reuse is done and every new request uses a
new connection. However, if http-reuse is set to never, the connection
are stored by the mux in the session and can be reused for future
requests in the same session.
As no server is used for these connections, no reuse can be made outside
of the session, similarly to http-reuse never mode. A different
http-reuse config value should not have an impact. To achieve this, mark
these connections as private to have a defined behavior.
For this feature to properly work, the connection hash has been slightly
adjusted. The server pointer as an input as been replaced by a generic
target pointer to refer to the server or proxy instance. The hash is
always calculated on connect_server even if the connection target is not
a server. This also requires to allocate the connection hash node for
every backend connections, not just the one with a server target.
Fix a leak in connect_server which happens when a connection is reused
and a bind_addr was allocated because transparent mode is active. The
connection has already an allocated bind_addr so free the newly
allocated one.
No backport needed.
That comma should've been a semicolon. Fortunately, as it is now there
is no impact thanks to operators precedence, and all expressions are
properly evaluated. But this is troubling and the risk is high to
turn it into an effective bug with a minor change.
Introduced in b8ce8905cf which first
appeared in 2.1-dev3. This fix must be backported to 2.1+.
Since this commit:
144289b45 ("REORG: move init_default_instance() to proxy.c and pass it the defproxy pointer")
as quic_transport_params_init() has been moved from cfgparse.c to proxy.c this
latter source file must include xprt_quic.h header.
Should fix#1153 issue.
When the processing stage is finished for a SPOE applet, before returning it
into the idle list, we check if the assigned server appears as full or if
there are some pending connections on the backend or the assigned server. If
yes, it means we reach a maxconn and we close the applet to free a
slot. Otherwise, the applet can be reused. This test is only performed if
there are more than one thread.
It is important to close SPOE applets when there are pending connections for
multithreaded instances because connections with the SPOE agents are
persistent and local to a thread (applets are local to a thread). If a
maxconn is configured, some threads may take all available slots for a
while, leaving remaining threads without any free slot to process SPOE
messages. It is especially true if the maxconn is low.
This patch should fix the issue #705. It must be backported as far as
1.8. However, the code in 1.8 is quite different, a test must be performed
to be sure it works well.
When the selected server has no address, the destination address of the
client is used. However, for now, only the address is set, not the
family. Thus depending on how the server is configured and the client's
destination address, the server address family may be wrong.
For instance, with such server :
server srv 0.0.0.0:0
The server address family is AF_INET. The server connection will fail if a
client is asking for an IPv6 destination.
To fix the bug, we take care to set the rigth family, the family of the
client destination address.
This patch should fix the issue #202. It must be backported to all stable
versions.
If an IPv4 is set via a TCP/HTTP set-dst rule, the original port must be
preserved or set to 0 if the previous family was neither AF_INET nor
AF_INET6. The first case is not an issue because the port remains the
same. But if the previous family was, for instance, AF_UNIX, the port is not
set to 0 and have an undefined value.
This patch must be backported as far as 1.7.
There was a free(ptr) followed by ptr=malloc(ptr, len), which is the
equivalent of ptr = realloc(ptr, len) but slower and less clean. Let's
replace this.
In ssl_sock_free_srv_ctx() there are some calls to free() which are not
followed by a zeroing of the pointers. For now this function is only used
during deinit but it could be used at run time in the near future, so
better secure this.
