On 2025-06-26 11:52, Dylan Yudaken wrote:
No reason to not allow MEMBARRIER_CMD_FLAG_CPU on
MEMBARRIER_CMD_PRIVATE_EXPEDITED or
MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE.
If it is known specifically what cpu you want to interrupt then there
is a decent efficiency saving in not interrupting all the other ones.
Also - the code already works as is for them.
Can you elaborate on a concrete use-case justifying adding this ?
Thanks,
Mathieu
Signed-off-by: Dylan Yudaken <dyuda...@gmail.com>
---
kernel/sched/membarrier.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c
index 809194cd779f..def6d4094ad6 100644
--- a/kernel/sched/membarrier.c
+++ b/kernel/sched/membarrier.c
@@ -595,7 +595,9 @@ static int membarrier_get_registrations(void)
* contains the CPU on which to interrupt (= restart)
* the RSEQ critical section.
* @cpu_id: if @flags == MEMBARRIER_CMD_FLAG_CPU, indicates the cpu on which
- * RSEQ CS should be interrupted (@cmd must be
+ * RSEQ CS should be interrupted (@cmd must be one of
+ * MEMBARRIER_CMD_PRIVATE_EXPEDITED,
+ * MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE,
* MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ).
*
* If this system call is not implemented, -ENOSYS is returned. If the
@@ -625,6 +627,8 @@ static int membarrier_get_registrations(void)
SYSCALL_DEFINE3(membarrier, int, cmd, unsigned int, flags, int, cpu_id)
{
switch (cmd) {
+ case MEMBARRIER_CMD_PRIVATE_EXPEDITED:
+ case MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE:
case MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ:
if (unlikely(flags && flags != MEMBARRIER_CMD_FLAG_CPU))
return -EINVAL;
--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com
