On Fri, Jul 29, 2011 at 04:53:21PM +1000, Greg Banks wrote: > On 29/07/11 16:30, Eric Dumazet wrote: > >Le vendredi 29 juillet 2011 à 16:05 +1000, Greg Banks a écrit : > >>On 29/07/11 15:32, NeilBrown wrote: > >> > >>I seem to remember coming to the conclusion that Jeff eventually > >>addressed this problem...am I misremembering or did something regress? > >> > >Currently, all nfsd kthreads use memory for their kernel stack and > >various initial data from a _single_ node, even if you use > >sunrpc.pool_mode=pernode (or percpu) > > That's just plain broken and I'm very pleased to see you fix it. Should I take that as a "Reviewed-by"? > I was just surprised that it was still broken and wondering how that > happened. Looking at ToT I see that because I dropped the ball in > 2008, Jeff's patches didn't address the problem. In ToT > svc_pool_map_set_cpumask() is called *after* kthread_create() and > applies to the child thread, *after* it's stack has been allocated > on the wrong node. In the working SGI code, > svc_pool_map_set_cpumask() is called by the parent node on itself > *before* calling kernel_thread() or doing any of the data structure > allocations, thus ensuring that everything gets allocated using the > default memory allocation policy, which on SGI NFS servers was > globally tuned to be "node-local". OK, so would it be enough to just move the svc_pool_map_set_cpumask() back a few lines, or do we want Eric's approach, in order to have something that will work better with other memory allocation policies? --b. > > >With my patch, we make sure each thread gets its stack from its local > >node. > > > >Check commit 94dcf29a11b3d20a (kthread: use kthread_create_on_node()) to > >see how this strategy already was adopted for ksoftirqd, kworker, > >migration, and pktgend kthreads. > > Ah, I see. It's unfortunate that the kthread_create() API ends up > being passed a CPU number but that's only used to format the name > and not for sensible things :( > > -- > Greg. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
