nfsd41: bound forechannel drc size by memory usage

By using the requested ca_maxresponsesize_cached * ca_maxresponses to bound
a forechannel drc request size, clients can tailor a session to usage.

For example, an I/O session (READ/WRITE only) can have a much smaller
ca_maxresponsesize_cached (for only WRITE compound responses) and a lot larger
ca_maxresponses to service a large in-flight data window.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

1 files changed, 6 insertions, 2 deletions

diff --git a/include/linux/nfsd/state.h b/include/linux/nfsd/state.h
index fb0c404c7c5c..ff0b771efde6 100644
--- a/include/linux/nfsd/state.h
+++ b/include/linux/nfsd/state.h
@@ -92,13 +92,17 @@ struct nfs4_cb_conn {
         struct rpc_cred *       cb_cred;
 };
 
-/* Maximum number of slots per session. 128 is useful for long haul TCP */
-#define NFSD_MAX_SLOTS_PER_SESSION      128
+/* Maximum number of slots per session. 160 is useful for long haul TCP */
+#define NFSD_MAX_SLOTS_PER_SESSION     160
 /* Maximum number of pages per slot cache entry */
 #define NFSD_PAGES_PER_SLOT     1
 #define NFSD_SLOT_CACHE_SIZE            PAGE_SIZE
 /* Maximum number of operations per session compound */
 #define NFSD_MAX_OPS_PER_COMPOUND       16
+/* Maximum number of NFSD_SLOT_CACHE_SIZE slots per session */
+#define NFSD_CACHE_SIZE_SLOTS_PER_SESSION       32
+#define NFSD_MAX_MEM_PER_SESSION  \
+                (NFSD_CACHE_SIZE_SLOTS_PER_SESSION * NFSD_SLOT_CACHE_SIZE)
 
 struct nfsd4_cache_entry {
         __be32          ce_status;