Commit:     ef48bd246124ccdef0e1fa5b03b62d69cbf71fa7
Parent:     4d3b573ad9af85b6df104044f6fff05f04349db2
Author:     Paul E. McKenney <[EMAIL PROTECTED]>
AuthorDate: Sun Jul 15 23:41:03 2007 -0700
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Mon Jul 16 09:05:47 2007 -0700

    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: Paul E. McKenney <[EMAIL PROTECTED]>
    Cc: Steven Rostedt <[EMAIL PROTECTED]>
    Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
 Documentation/RCU/checklist.txt |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt
index f4dffad..42b01bc 100644
--- a/Documentation/RCU/checklist.txt
+++ b/Documentation/RCU/checklist.txt
@@ -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()),
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