Here's a resend of the deferral patch set for review , responding to comments on the last patch set. A deferral occurs when NFSD needs information from an rpc cache, and an upcall is required. Instead of NFSD waiting for the cache to be filled by the upcall, the RPC request is inserted back into the receive stream for processing at a later time. Exactly once semantics require that NFSD compound RPC deferral processing restart at the operation that caused the deferral, instead of reprocessing the full compound RPC from the start possibly repeating operation processing. These patches add three callbacks, a data pointer, and dynamic page pointer storage to the sunrpc svc deferral architecture that NFSD uses to accomplish this goal. Deferrals that do not define the callbacks act as before. Care has been taken to ensure that combinations of deferrals - those from the NFSv4 server with the callbacks defined, and those from the RPC layer without the callbacks defined work together correctly. NEW: I've limited the number of pages held by all deferrals to the number of pages in the rpc maximum payload - the same as adding another nfsd thread. Most deferrals (most requests) fit in a page or two. We want to service the rare deferral where a large readdir or read reply is followed by a deferral, this limit allows the servicing of one such request at time. I've changed the deferral page pointer storage from static to dynamic. The new svc_rqst fields are initialized in the beginning of svc_process along with the rest of the fields. As always, thoughts, comments and suggestions welcome. -->Andy -- 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
