On Tue, 26 Jun 2018, Andrea Parri wrote:

quoted

quoted

-A write memory barrier is implied by wake_up() and co.  if and only if they
-wake something up.  The barrier occurs before the task state is cleared, and so
-sits between the STORE to indicate the event and the STORE to set TASK_RUNNING:
+A general memory barrier is executed by wake_up() if it wakes something up.
+If it doesn't wake anything up then a memory barrier may or may not be
+executed; you must not rely on it.  The barrier occurs before the task state
+is accessed, in part., it sits between the STORE to indicate the event and
+the STORE to set TASK_RUNNING:

Minor suggestion: Instead of "in part.", how about "that is"?

(I generally find "in part." to be at least a little confusing,
probably because "part" is itself a word and "in part" is a 
reasonably common phrase in English.)

Mmh, the fact is that that "before the task state is accessed" does want
to include the LOAD from ->state to check for the task state (recall the
pattern in [1])...; how about if I expand "in part." to "in particular"?

That would be acceptable.

Alan

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