Example of usage:
error_log memory:16m debug;
This allows to configure debug logging with minimum impact on performance.
It's especially useful when rare crashes are experienced under high load.
The log can be extracted from a coredump using the following gdb script:
set $log = ngx_cycle->log
while $log->writer != ngx_log_memory_writer
set $log = $log->next
end
set $buf = (ngx_log_memory_buf_t *) $log->wdata
dump binary memory debug_log.txt $buf->start $buf->end
Initial size as calculated from the number of elements may be bigger
than max_size. If this happens, make sure to set size to max_size.
Reported by Chris West.
Previously, this function checked for connection local address existence
and returned error if it was missing. Now a new address is assigned in this
case making it possible to call this function not only for accepted connections.
It appeared that the NGX_HAVE_AIO_SENDFILE macro was defined regardless of
the "--with-file-aio" configure option and the NGX_HAVE_FILE_AIO macro.
Now they are related.
Additionally, fixed one macro.
This reduces layering violation and simplifies the logic of AIO preread, since
it's now triggered by the send chain function itself without falling back to
the copy filter. The context of AIO operation is now stored per file buffer,
which makes it possible to properly handle cases when multiple buffers come
from different locations, each with its own configuration.
The mtx->wait counter was not decremented if we were able to obtain the lock
right after incrementing it. This resulted in unneeded sem_post() calls,
eventually leading to EOVERFLOW errors being logged, "sem_post() failed
while wake shmtx (75: Value too large for defined data type)".
To close the race, mtx->wait is now decremented if we obtain the lock right
after incrementing it in ngx_shmtx_lock(). The result can become -1 if a
concurrent ngx_shmtx_unlock() decrements mtx->wait before the added code does.
However, that only leads to one extra iteration in the next call of
ngx_shmtx_lock().
The use_temp_path http cache feature is now implemented using a separate temp
hierarchy in cache directory. Prefix-based temp files are no longer needed.
The original check for NGX_AGAIN was surplus, since the function returns
only NGX_OK or NGX_ERROR. Now it looks similar to other places.
No functional changes.
In 954867a2f0a6, we switched to using resolver node as the timer event data.
This broke debug event logging.
Replaced now unused ngx_resolver_ctx_t.ident with ngx_resolver_node_t.ident
so that ngx_event_ident() extracts something sensible when accessing
ngx_resolver_node_t as ngx_connection_t.
In 954867a2f0a6, we switched to using resolver node as the
timer event data, so make sure we do not free resolver node
memory until the corresponding timer is deleted.
If a syslog daemon is restarted and the unix socket is used, further logging
might stop to work. In case of send error, socket is closed, forcing
a reconnection at the next logging attempt.
The ngx_cycle->log is used when sending the message. This allows to log syslog
send errors in another log.
Logging to syslog after its cleanup handler has been executed was prohibited.
Previously, this was possible from ngx_destroy_pool(), which resulted in error
messages caused by attempts to write into the closed socket.
The "processing" flag is renamed to "busy" to better match its semantics.
In theory, this can provide a bit better distribution of latencies.
Also it simplifies the code, since ngx_queue_t is now used instead
of custom implementation.
RFC3986 says that, for consistency, URI producers and normalizers
should use uppercase hexadecimal digits for all percent-encodings.
This is also what modern web browsers and other tools use.
Using lowercase hexadecimal digits makes it harder to interact with
those tools in case when use of the percent-encoded URI is required,
for example when $request_uri is part of the cache key.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
The check became meaningless after refactoring in 2a92804f4109.
With the loop currently in place, "current" can't be NULL, hence
the check can be dropped.
Additionally, the local variable "current" was removed to
simplify code, and pool->current now used directly instead.
Found by Coverity (CID 714236).
This isn't really important as configuration testing shortly ends with
a process termination which will free all sockets, though Coverity
complains.
Prodded by Coverity (CID 400872).
Large allocations from a slab pool result in free page blocks being fragmented,
eventually leading to a situation when no further allocation larger than a page
size are possible from the pool. While this isn't a problem for nginx itself,
it is known to be bad for various 3rd party modules. Fix is to merge adjacent
blocks of free pages in the ngx_slab_free_pages() function.
Prodded by Wandenberg Peixoto and Yichun Zhang.
Previous code failed to properly restore cf->conf_file in case of
ngx_close_file() errors, potentially resulting in double free of
cf->conf_file->buffer->start.
Found by Coverity (CID 1087507).
The flag allows to suppress "ngx_slab_alloc() failed: no memory" messages
from a slab allocator, e.g., if an LRU expiration is used by a consumer
and allocation failures aren't fatal.
The flag is now used in the SSL session cache code, and in the limit_req
module.
Client address specified in the PROXY protocol header is now
saved in the $proxy_protocol_addr variable and can be used in
the realip module.
This is currently not implemented for mail.
Linux returns EOPNOTSUPP for non-TCP sockets and ENOPROTOOPT for TCP
sockets, because getsockopt(TCP_FASTOPEN) is not implemented so far.
While there, lower the log level from ALERT to NOTICE to match other
getsockopt() failures.
Signed-off-by: Piotr Sikora <piotr@cloudflare.com>
Backed out 05a56ebb084a, as it turns out that kernel can return connections
without any delay if syncookies are used. This basically means we can't
assume anything about connections returned with deferred accept set.
To solve original problem the 05a56ebb084a tried to solve, i.e. to don't
wait longer than needed if a connection was accepted after deferred accept
timeout, this patch changes a timeout set with setsockopt(TCP_DEFER_ACCEPT)
to 1 second, unconditionally. This is believed to be enough for speed
improvements, and doesn't imply major changes to timeouts used.
Note that before 2.6.32 connections were dropped after a timeout. Though
it is believed that 1s is still appropriate for kernels before 2.6.32,
as previously tcp_synack_retries controlled the actual timeout and 1s results
in more than 1 minute actual timeout by default.
Previously pool->current wasn't moved back to pool, resulting in blocks
not used for further allocations if pool->current was already moved at the
time of ngx_reset_pool(). Additionally, to preserve logic of moving
pool->current, the p->d.failed counters are now properly cleared. While
here, pool->chain is also cleared.
This change is essentially a nop with current code, but generally improves
things.
Fallback to synchronous sendfile() now only done on 3rd EBUSY without
any progress in a row. Not falling back is believed to be better
in case of occasional EBUSY, though protection is still needed to
make sure there will be no infinite loop.
