Messages in this thread | | | Date | Thu, 2 Jun 2005 17:08:20 -0700 | From | Ashok Raj <> | Subject | Re: [patch 2/5] x86_64: CPU hotplug support. |
| |
On Thu, Jun 02, 2005 at 05:45:14PM -0600, Zwane Mwaikambo wrote: > On Thu, 2 Jun 2005, Ashok Raj wrote: > > > > > + lock_ipi_call_lock(); > > > > cpu_set(smp_processor_id(), cpu_online_map); > > > > mb(); > > > > + unlock_ipi_call_lock(); > > > > > > What's that? Is this another smp_call_function race workaround? I thought > > > there was an additional patch to avoid the broadcast. > > > > The other patch avoids sending to offline cpu's, but we read cpu_online_map > > and clear self bit in smp_call_function. If a cpu comes online, dont we > > want this cpu to take part in smp_call_function? > > The lock being held in smp_call_function whilst we access cpu_online_map > should prevent another processor coming online within that operation > shouldn't it? So There shouldn't be any processors coming online except > for right after or before an smp_call_function.
precicely why we hold the same lock when we set the bit in cpu_online_map during cpu_up as well. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |