@@ -495,9 +495,10 @@ void __smp_call_single_queue(int cpu, struct llist_node *node)
#endif
/*
- * The list addition should be visible before sending the IPI
- * handler locks the list to pull the entry off it because of
- * normal cache coherency rules implied by spinlocks.
+ * The list addition should be visible to the target CPU when it pops
+ * the head of the list to pull the entry off it in the IPI handler
+ * because of normal cache coherency rules implied by the underlying
+ * llist ops.
*
* If IPIs can go out of order to the cache coherency protocol
* in an architecture, sufficient synchronisation should be added
Accessing the call_single_queue hasn't involved a spinlock since 2014: 6897fc22ea01 ("kernel: use lockless list for smp_call_function_single") The llist operations (namely cmpxchg() and xchg()) provide similar ordering guarantees, update the comment to lessen confusion. Signed-off-by: Valentin Schneider <vschneid@redhat.com> --- kernel/smp.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)