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 dyudaken@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;