75c3f9f880 sync: rename AnnotatedMixin::UniqueLock to AnnotatedMixin::unique_lock (Vasil Dimov)
8d9ee8efe8 sync: remove DebugLock alias template (Vasil Dimov)
4b2e16763f sync: avoid confusing name overlap (Mutex) (Vasil Dimov)
9d7ae4b66c sync: remove unused template parameter from ::UniqueLock (Vasil Dimov)
11c190e3f1 sync: simplify MaybeCheckNotHeld() definitions by using a template (Vasil Dimov)
Pull request description:
Summary:
* Reduce 4 of the `MaybeCheckNotHeld()` definitions to 2 by using a template.
* Remove unused template parameter from `::UniqueLock`.
* Use `MutexType` instead of `Mutex` for a template parameter name to avoid overlap/confusion with the `Mutex` class.
* Rename `AnnotatedMixin::UniqueLock` to `AnnotatedMixin::unique_lock` to avoid overlap/confusion with the global `UniqueLock` and for consistency with `UniqueLock::reverse_lock`.
The first commit `sync: simplify MaybeCheckNotHeld() definitions by using a template` is also part of https://github.com/bitcoin/bitcoin/pull/25390
ACKs for top commit:
aureleoules:
ACK 75c3f9f880 - LGTM
ryanofsky:
Code review ACK 75c3f9f880. Nice cleanups! Just suggested changes since last review: keeping UniqueLock name and fixing a missed rename in a code comment
Tree-SHA512: ec261f6a444bdfe4f06e844b57b3606fdd9b2f842647cae15266d9729970d87585c808d482fbba0b31c33a4aa03527c36e282c92b28d9052711f75a7048c96f1
Use `UniqueLock` directly. Type deduction works just fine from the first
argument to the constructor of `UniqueLock`, so there is no need to
repeat
```cpp
UniqueLock<typename std::remove_reference<typename std::remove_pointer<decltype(cs)>::type>::type>
```
five times in the `LOCK` macros. Just `UniqueLock` suffices.
Use `MutexType` instead of `Mutex` for the template parameter of
`UniqueLock` because there is already a class named `Mutex` and the
naming overlap is confusing. `MutexType` is used elsewhere in `sync.h`.
Microsoft's C++ Standard Library uses the `[[nodiscard]]` attribute for
`try_lock()`.
See: https://github.com/microsoft/STL/blob/main/stl/inc/mutex
This change allows to drop the current suppression for the warning C4838
and helps to prevent the upcoming warning C4858.
See: 539c26c923
The template parameter `typename Base = typename Mutex::UniqueLock` is
not used, so remove it. Use internally defined type `Base` to avoid
repetitions of `Mutex::UniqueLock`.
in microseconds.
Change the function name in order to print "LockContention" instead
of "PrintLockContention" to the log. Add Doxygen documentation.
With this change, the lock contention log prints:
2021-09-01T11:29:03Z LockContention: pnode->cs_vSend, net.cpp:1373 started
2021-09-01T11:29:03Z LockContention: pnode->cs_vSend, net.cpp:1373 completed (31μs)
2021-09-01T11:29:03Z LockContention: cs_vNodes, net.cpp:2277 started
2021-09-01T11:29:03Z LockContention: cs_vNodes, net.cpp:2277 completed (6μs)
2021-09-01T11:29:04Z LockContention: cs_vNodes, net.cpp:2242 started
2021-09-01T11:29:04Z LockContention: cs_vNodes, net.cpp:2242 completed (3μs)
Co-authored-by: Hennadii Stepanov <32963518+hebasto@users.noreply.github.com>
Co-authored-by: practicalswift <practicalswift@users.noreply.github.com>
3eb94ec81b sync: Use decltype(auto) return type for WITH_LOCK (Carl Dong)
Pull request description:
> Now that we're using C++17, we can use the decltype(auto) return type
> for functions and lambda expressions.
>
> As demonstrated in this commit, this can simplify cases where previously
> the compiler failed to deduce the correct return type.
>
> Just for reference, for the "assign to ref" cases fixed here, there are
> 3 possible solutions:
>
> - Return a pointer and immediately deref as used before this commit
> - Make sure the function/lambda returns declspec(auto) as used after
> this commit
> - Class& i = WITH_LOCK(..., return std::ref(...));
>
> -----
>
> References:
> 1. https://en.cppreference.com/w/cpp/language/function#Return_type_deduction
> 2. https://en.cppreference.com/w/cpp/language/template_argument_deduction#Other_contexts
> 3. https://en.cppreference.com/w/cpp/language/auto
> 4. https://en.cppreference.com/w/cpp/language/decltype
>
> Explanations:
> 1. https://stackoverflow.com/a/21369192
> 2. https://stackoverflow.com/a/21369170
Thanks to sipa and ryanofsky for helping me understand this
ACKs for top commit:
jnewbery:
utACK 3eb94ec81b
hebasto:
ACK 3eb94ec81b, I have reviewed the code and it looks OK, I agree it can be merged. I have verified possible warnings:
ryanofsky:
Code review ACK 3eb94ec81b
Tree-SHA512: 5f55c7722aeca8ea70e5c1a8db93e93ba0e356e8967e7f607ada38003df4b153d73c29bd2cea8d7ec1344720d37d857ea7dbfd2a88da1d92e0e9cbb9abd287df
95975dd08d sync: detect double lock from the same thread (Vasil Dimov)
4df6567e4c sync: make EnterCritical() & push_lock() type safe (Vasil Dimov)
Pull request description:
Double lock of the same (non-recursive) mutex from the same thread would produce an undefined behavior. Detect this from `DEBUG_LOCKORDER` and react similarly to the deadlock detection.
This came up during discussion in another, related PR: https://github.com/bitcoin/bitcoin/pull/19238#discussion_r442394521.
ACKs for top commit:
laanwj:
code review ACK 95975dd08d
hebasto:
re-ACK 95975dd08d
Tree-SHA512: 375c62db7819e348bfaecc3bd82a7907fcd8f5af24f7d637ac82f3f16789da9fc127dbd0e37158a08e0dcbba01a55c6635caf1d8e9e827cf5a3747f7690a498e
The functions `EnterCritical()` and `push_lock()` take a pointer to a
mutex, but that pointer used to be of type `void*` because we use a few
different types for mutexes. This `void*` argument was not type safe
because somebody could have send a pointer to anything that is not a
mutex. Furthermore it wouldn't allow to check whether the passed mutex
is recursive or not.
Thus, change the functions to templated ones so that we can implement
stricter checks for non-recursive mutexes. This also simplifies the
callers of `EnterCritical()`.
FoundBlock class allows interfaces::Chain::findBlock to return more block
information without having lots of optional output parameters. FoundBlock class
is also used by other chain methods in upcoming commits.
There is mostly no change in behavior. Only exception is
CWallet::RescanFromTime now throwing NonFatalCheckError instead of
std::logic_error.
-BEGIN VERIFY SCRIPT-
# Delete outdated alias for RecursiveMutex
sed -i -e '/CCriticalSection/d' ./src/sync.h
# Replace use of outdated alias with RecursiveMutex
sed -i -e 's/CCriticalSection/RecursiveMutex/g' $(git grep -l CCriticalSection)
-END VERIFY SCRIPT-
Call sync.h primitives "locks" and "mutexes" instead of "blocks" and "waitable
critical sections" to match current coding conventions and c++11 standard
names.
This PR does not rename the "CCriticalSection" class (though this could be done
as a followup) because it is used everywhere and would swamp the other changes
in this PR. Plain mutexes should mostly be preferred instead of recursive
mutexes in new code anyway.
-BEGIN VERIFY SCRIPT-
set -x
set -e
ren() { git grep -l $1 | xargs sed -i s/$1/$2/; }
ren CCriticalBlock UniqueLock
ren CWaitableCriticalSection Mutex
ren CConditionVariable std::condition_variable
ren cs_GenesisWait g_genesis_wait_mutex
ren condvar_GenesisWait g_genesis_wait_cv
perl -0777 -pi -e 's/.*typedef.*condition_variable.*\n\n?//g' src/sync.h
-END VERIFY SCRIPT-
9c4dc597dd Use LOCK macros for non-recursive locks (Russell Yanofsky)
1382913e61 Make LOCK, LOCK2, TRY_LOCK work with CWaitableCriticalSection (Russell Yanofsky)
ba1f095aad MOVEONLY Move AnnotatedMixin declaration (Russell Yanofsky)
41b88e9337 Add unit test for DEBUG_LOCKORDER code (Russell Yanofsky)
Pull request description:
Make LOCK macros work with non-recursive mutexes, and use wherever possible for better deadlock detection.
Also add unit test for DEBUG_LOCKORDER code.
Tree-SHA512: 64ef209307f28ecd0813a283f15c6406138c6ffe7f6cbbd084161044db60e2c099a7d0d2edcd1c5e7770a115e9b931b486e86c9a777bdc96d2e8a9f4dc192942
They should also work with any other mutex type which std::unique_lock
supports.
There is no change in behavior for current code that calls these macros with
CCriticalSection mutexes.
