Commit 0825458b authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

documentation: Composability analogies 



This commit expands on RCU's composability by comparing it to that of
transactional memory and of locking.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 01d3ad38

Documentation/RCU/Design/Requirements/Requirements.html

+8 −0
Original line number Diff line number Diff line
@@ -1494,6 +1494,14 @@ in RCU implicitly splitting the enclosing RCU read-side critical 
section, neither of which is conducive to a long-lived and prosperous

kernel.



<p>

It is worth noting that RCU is not alone in limiting composability.

For example, many transactional-memory implementations prohibit

composing a pair of transactions separated by an irrevocable

operation (for example, a network receive operation).

For another example, lock-based critical sections can be composed

surprisingly freely, but only if deadlock is avoided.



<p>

In short, although RCU read-side critical sections are highly composable,

care is required in some situations, just as is the case for any other

Documentation/RCU/Design/Requirements/Requirements.htmlx

+8 −0
Original line number Diff line number Diff line
@@ -1653,6 +1653,14 @@ in RCU implicitly splitting the enclosing RCU read-side critical 
section, neither of which is conducive to a long-lived and prosperous

kernel.



<p>

It is worth noting that RCU is not alone in limiting composability.

For example, many transactional-memory implementations prohibit

composing a pair of transactions separated by an irrevocable

operation (for example, a network receive operation).

For another example, lock-based critical sections can be composed

surprisingly freely, but only if deadlock is avoided.



<p>

In short, although RCU read-side critical sections are highly composable,

care is required in some situations, just as is the case for any other

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