diff options
| author | Andres Freund | 2025-02-22 01:55:23 +0000 |
|---|---|---|
| committer | Andres Freund | 2025-02-22 01:55:23 +0000 |
| commit | f8d7f29b3e81db59b95e4b5baaa6943178c89fd8 (patch) | |
| tree | 2ccdf0f312519fc66957d68a876b64c648ed367f /src/include | |
| parent | 44cbba9a7f51a3888d5087fc94b23614ba2b81f2 (diff) | |
Allow lwlocks to be disowned
To implement AIO writes, the backend initiating writes needs to transfer the
lock ownership to the AIO subsystem, so the lock held during the write can be
released in another backend.
Other backends need to be able to "complete" an asynchronously started IO to
avoid deadlocks (consider e.g. one backend starting IO for a buffer and then
waiting for a heavyweight lock held by another relation followed by the
current holder of the heavyweight lock waiting for the IO to complete).
To that end, this commit adds LWLockDisown() and LWLockReleaseDisowned(). If
code uses LWLockDisown() it's the code's responsibility to ensure that the
lock is released in case of errors.
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: https://postgr.es/m/1f6b50a7-38ef-4d87-8246-786d39f46ab9@iki.fi
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/storage/lwlock.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h index 2aa46fd50da..13a7dc89980 100644 --- a/src/include/storage/lwlock.h +++ b/src/include/storage/lwlock.h @@ -129,6 +129,8 @@ extern bool LWLockAcquireOrWait(LWLock *lock, LWLockMode mode); extern void LWLockRelease(LWLock *lock); extern void LWLockReleaseClearVar(LWLock *lock, pg_atomic_uint64 *valptr, uint64 val); extern void LWLockReleaseAll(void); +extern void LWLockDisown(LWLock *l); +extern void LWLockReleaseDisowned(LWLock *l, LWLockMode mode); extern bool LWLockHeldByMe(LWLock *lock); extern bool LWLockAnyHeldByMe(LWLock *lock, int nlocks, size_t stride); extern bool LWLockHeldByMeInMode(LWLock *lock, LWLockMode mode); |