KeRcuSynchronize function (wdm.h)

The KeRcuSynchronize function waits for a grace period to elapse in the default RCU (Read-Copy-Update) domain, ensuring that all pre-existing RCU read-side critical sections have completed.

Syntax

VOID KeRcuSynchronize();

Return value

None

Remarks

KeRcuSynchronize is a blocking operation that waits for a grace period using a kernel gate object. It must be called at IRQL < DISPATCH_LEVEL (typically PASSIVE_LEVEL) because it can cause the calling thread to be suspended.

This function blocks the calling thread until all RCU read-side critical sections that were active at the time of the call have exited. It provides a synchronization point for writers to safely reclaim or modify RCU-protected data structures.

KeRcuSynchronize guarantees that:

• All RCU read-side critical sections that began before the call to KeRcuSynchronize will complete before the function returns.
• It's safe to reclaim memory or data structures protected by RCU after this function returns.
• New readers that begin after KeRcuSynchronize starts may or may not be waited for.

This function is typically used in update-side code paths where the caller needs to ensure that all readers have finished accessing data structures before safely reclaiming or modifying them.

The function is non-failing. It will always complete successfully and cannot return an error.

For more complex scenarios requiring custom synchronization domains, use KeSrcuSynchronize with an explicit SRCU partition.

Requirements

See also

KeRcuReadLock

KeRcuReadUnlock

KeSrcuSynchronize

KeSrcuAllocate

KeSrcuFree