On Wed, 2011-05-04 at 11:18 +1000, NeilBrown wrote: > For rpc slots, I doubt you need mempools at all. > Mempools are only needed if failure is not an option and you would rather > wait, but you cannot wait for regular writeback because you are on the > writeback path. So you use a mempool which waits for a previous request to > complete. I don't think that describes rpc slots at all. > For rpc slots, you can afford to wait when setting up the transport, as you > are not on the writeout path yet, and later you can always cope with failure. > So just use kmalloc. Errr.... No. By the time you get to allocating an RPC slot, you may be bang smack in the middle of the writeout path. The scenario would be that something triggers a writeback (kswapd, direct reclaim,...) which triggers an RPC call, which requires you to allocate at least one rpc slot before you can put the write on the wire. I agree with your assertion that we only need one successful slot allocation in order to make overall forward progress, but we definitely do need that one... -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@xxxxxxxxxx www.netapp.com -- 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
