Replace the isc_mutex in the dns_adb unit with isc_rwlock for better
performance. Both ADB names and ADB entries hashtables and LRU are now
using isc_rwlock.
This changes the internal isc_rwlock implementation to:
Irina Calciu, Dave Dice, Yossi Lev, Victor Luchangco, Virendra
J. Marathe, and Nir Shavit. 2013. NUMA-aware reader-writer locks.
SIGPLAN Not. 48, 8 (August 2013), 157–166.
DOI:https://doi.org/10.1145/2517327.24425
(The full article available from:
http://mcg.cs.tau.ac.il/papers/ppopp2013-rwlocks.pdf)
The implementation is based on the The Writer-Preference Lock (C-RW-WP)
variant (see the 3.4 section of the paper for the rationale).
The implemented algorithm has been modified for simplicity and for usage
patterns in rbtdb.c.
The changes compared to the original algorithm:
* We haven't implemented the cohort locks because that would require a
knowledge of NUMA nodes, instead a simple atomic_bool is used as
synchronization point for writer lock.
* The per-thread reader counters are not being used - this would
require the internal thread id (isc_tid_v) to be always initialized,
even in the utilities; the change has a slight performance penalty,
so we might revisit this change in the future. However, this change
also saves a lot of memory, because cache-line aligned counters were
used, so on 32-core machine, the rwlock would be 4096+ bytes big.
* The readers use a writer_barrier that will raise after a while when
readers lock can't be acquired to prevent readers starvation.
* Separate ingress and egress readers counters queues to reduce both
inter and intra-thread contention.
The dns_badcache was pulling the <isc/atomic.h> header only indirectly
via <isc/rwlock.h>, add the direct include as the <isc/rwlock.h> no
longer pulls the header when pthread_rwlock is used.
Include MD5 feature detection in featuretest tool and use it in some
places. When RHEL distribution or Fedora ELN is in FIPS mode, then MD5
algorithm is unavailable completely and even hmac-md5 algorithm usage
will always fail. Work that around by checking MD5 works and if not,
skipping its usage.
Those changes were dragged as downstream patch bind-9.11-fips-tests.patch
in Fedora and RHEL.
I misunderstood the purpose of the `heap_index` rdataset header
member; I thought it identified which heap to use, and could therefore
be smaller, the same size as `locknum` indexes. But in fact it is a
position within a heap, so it needs to be able to count up to the
total number of rdatasets in the rbtdb.
So this changes `heap_index` from `uint16_t` back to `unsigned int`.
To avoid re-embiggening the rdatasetheader, shrink the `count` member
from `uint32` to `uint16`. The `count` is used to rotate RRsets in
`dns_rdataset_towiresorted()`, so 16 bits is more than large enough.
This change also means we no longer need to avoid colliding with
`DNS_RDATASET_COUNT_UNDEFINED` i.e. UINT32_MAX.
Closes#3862
Unfortunately, C still lacks a standard function for pause (x86,
sparc) or yeild (arm) instructions, for use in spin lock or CAS loops.
BIND has its own based on vendor intrinsics or inline asm.
Previously, it was buried in the `isc_rwlock` implementation. This
commit renames `isc_rwlock_pause()` to `isc_pause()` and moves
it into <isc/pause.h>.
This commit also fixes the configure script so that it detects ARM
yield support on systems that identify as `aarch*` instead of `arm*`.
On 64-bit ARM systems we now use the ISB (instruction synchronization
barrier) instruction in preference to yield. The ISB instruction
pauses the CPU for longer, several nanoseconds, which is more like the
x86 pause instruction. There are more details in a Rust pull request,
which also refers to MySQL making the same change:
https://github.com/rust-lang/rust/pull/84725
Tests using diff to compare outputs of dig +short shall ignore lines
starting with ";". In dig +short output, such lines should only be
present for errors such as network issues. Since we utilize dig's
default timeout/retry mechanisms, these transitory issues should be
ignored and only the final output should be considered during the diff
comparison.
A dns_rpz_unref_rpzs() call is missing when taking the 'goto unlock;'
path on shutdown, in order to compensate for the earlier
dns_rpz_ref_rpzs() call.
Move the dns_rpz_ref_rpzs() call after the shutdown check.
This adds an island of trust that is reachable from the root
where the trust anchors are added to island.conf.
This add an island of trust that is not reachable from the root
where the trust anchors are added to private.conf.
When there are multiple managed trust anchors we need to know the
name of the trust anchor that is failing. Extend the error message
to include the trust anchor name.
removed some functions that are no longer used and unlikely to
be resurrected, and also some that were only used to support Windows
and can now be replaced with generic versions.
Occasionally, the allotted 10 seconds for the "running" line to appear
in log after named is started proved insufficient in CI, especially
during increased load. Give named up to 60 seconds to start up to
mitigate this issue.
The script will start the named process configured as both an
authoritative and recursive server for each pairwise ./configure
configuration. The test is considered successful if the named process
runs until the 5-second timeout is triggered, and there is no named.lock
file present, indicating that named did not crash on shutdown.
Add magic value to the fctxcount, to check for completely invalid
counters, or counters that have been already destroyed.
Improve the locking around the counters, and because of that we can drop
the atomics and use simple integers - the counters were already locked
and the tiny bits that used the atomics were not worth the extra effort.
- removed documentation of -S option from named man page
- removed documentation of reserved-sockets from ARM
- simplified documentation of dnssec-secure-to-insecure - it
now just says it's obsolete rather than describing what it
doesn't do anymore
- marked three formerly obsolete options as ancient:
parent-registration-delay, reserved-sockets, and
suppress-initial-notify
Add an extra job for a build from tarball, but without sphinx-build and
enable RUN_MAKE_INSTALL to check that man pages were generated and
installed.
Disable the RUN_MAKE_INSTALL on the systems without sphinx-build (sid).
We don't need them in the repo, it's sufficient if we pregenerate them
while preparing the tarball. That way we don't have overhead while
modifying them but they are still available for installations without
Sphinx.
I assume that this will make rebases and cherry-picks across branches
easier, with less trial and error churn required in the CI.
It's implemented in the way that we build the manpages only when we
either have pregenerated pages available at the configure time or
sphinx-build is installed and working.
isc_bind9 was a global bool used to indicate whether the library
was being used internally by BIND or by an external caller. external
use is no longer supported, but the variable was retained for use
by dyndb, which needed it only when being built without libtool.
building without libtool is *also* no longer supported, so the variable
can go away.
libuv support for receiving multiple UDP messages in a single system
call (recvmmsg()) has been tweaked several times between libuv versions
1.35.0 and 1.40.0. Mixing and matching libuv versions within that span
may lead to assertion failures and is therefore considered harmful, so
try to limit potential damage be preventing users from mixing libuv
versions with distinct sets of recvmmsg()-related flags.
The implementation of UDP recvmmsg in libuv 1.35 and 1.36 is
incomplete and could cause assertion failure under certain
circumstances.
Modify the configure and runtime checks to report a fatal error when
trying to compile or run with the affected versions.
Send the test message from ns3 to ns2 instead of ns2 to ns3 as ns2
is started first and therefore the test doesn't have to wait on the
resend of the the NOTIFY message to be successful.
