NFS: support large reads and writes on the wire
Most NFS server implementations allow up to 64KB reads and writes on the
wire. The Solaris NFS server allows up to a megabyte, for instance.
Now the Linux NFS client supports transfer sizes up to 1MB, too. This will
help reduce protocol and context switch overhead on read/write intensive NFS
workloads, and support larger atomic read and write operations on servers
that support them.
Test-plan:
Connectathon and iozone on mount point with wsize=rsize>32768 over TCP.
Tests with NFS over UDP to verify the maximum RPC payload size cap.
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index f69d95a..fd7ac5e 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -154,6 +154,7 @@
struct list_head *list;
struct nfs_direct_req *dreq;
unsigned int reads = 0;
+ unsigned int rpages = (rsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
dreq = kmem_cache_alloc(nfs_direct_cachep, SLAB_KERNEL);
if (!dreq)
@@ -167,7 +168,7 @@
list = &dreq->list;
for(;;) {
- struct nfs_read_data *data = nfs_readdata_alloc();
+ struct nfs_read_data *data = nfs_readdata_alloc(rpages);
if (unlikely(!data)) {
while (!list_empty(list)) {
@@ -431,7 +432,7 @@
struct nfs_writeverf first_verf;
struct nfs_write_data *wdata;
- wdata = nfs_writedata_alloc();
+ wdata = nfs_writedata_alloc(NFS_SERVER(inode)->wpages);
if (!wdata)
return -ENOMEM;