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Commit ef48bd24 authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Linus Torvalds
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Document the fact that RCU callbacks can run in parallel 



Add an item to the RCU documentation checklist noting that RCU callbacks
can run in parallel.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4d3b573a

Documentation/RCU/checklist.txt

+9 −1
Original line number Diff line number Diff line
@@ -222,7 +222,15 @@ over a rather long period of time, but improvements are always welcome! 
	deadlock as soon as the RCU callback happens to interrupt that

	acquisition's critical section.



13.	SRCU (srcu_read_lock(), srcu_read_unlock(), and synchronize_srcu())

13.	RCU callbacks can be and are executed in parallel.  In many cases,

	the callback code simply wrappers around kfree(), so that this

	is not an issue (or, more accurately, to the extent that it is

	an issue, the memory-allocator locking handles it).  However,

	if the callbacks do manipulate a shared data structure, they

	must use whatever locking or other synchronization is required

	to safely access and/or modify that data structure.



14.	SRCU (srcu_read_lock(), srcu_read_unlock(), and synchronize_srcu())

	may only be invoked from process context.  Unlike other forms of

	RCU, it -is- permissible to block in an SRCU read-side critical

	section (demarked by srcu_read_lock() and srcu_read_unlock()),