Change Details

Add a synchronizing instruction to flush and wait until the local CPU's writes are observable to other CPUs before sending IPIs. This fixes an issue where recipient CPUs doing a rendezvous could enter the rendezvous handling code before the initiator's writes to the smp_rv_* variables were visible. This manifested as a system hang, where a single CPU's increment of smp_rv_waiters[0] actually happened "before" the initiator's zeroing of that field, so all CPUs were stuck with the field appearing to be at ncpus - 1. MFC After: 1 week Sponsored by: Ampere Computing, Inc.

Add a synchronizing instruction to flush and wait until the local CPU's writes are observable to other CPUs before sending IPIs. This fixes an issue where recipient CPUs doing a rendezvous could enter the rendezvous handling code before the initiator's writes to the smp_rv_* variables were visible. This manifested as a system hang, where a single CPU's increment of smp_rv_waiters[0] actually happened "before" the initiator's zeroing of that field, so all CPUs were stuck with the field appearing to be at ncpus - 1. MFC after: 1 week Sponsored by: Ampere Computing, Inc.

Add a synchronizing instruction to flush and wait until the local CPU's writes are observable to other CPUs before sending IPIs. This fixes an issue where recipient CPUs doing a rendezvous could enter the rendezvous handling code before the initiator's writes to the smp_rv_* variables were visible. This manifested as a system hang, where a single CPU's increment of smp_rv_waiters[0] actually happened "before" the initiator's zeroing of that field, so all CPUs were stuck with the field appearing to be at ncpus - 1. MFC Aafter: 1 week Sponsored by: Ampere Computing, Inc.