pNFS: Don't allocate more pages than we need to fit a layoutget response

For the 'files' and 'flexfiles' layout types, we do not expect the reply
to be any larger than 4k. The block and scsi layout types are a little more
greedy, so we keep allocating the maximum response size for now.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/fs/nfs/filelayout/filelayout.c b/fs/nfs/filelayout/filelayout.c
index d175724..61f46fa 100644 (file)
--- a/fs/nfs/filelayout/filelayout.c
+++ b/fs/nfs/filelayout/filelayout.c
@@ -1164,6 +1164,7 @@ static struct pnfs_layoutdriver_type filelayout_type = {
        .id                     = LAYOUT_NFSV4_1_FILES,
        .name                   = "LAYOUT_NFSV4_1_FILES",
        .owner                  = THIS_MODULE,
+       .max_layoutget_response = 4096, /* 1 page or so... */
        .alloc_layout_hdr       = filelayout_alloc_layout_hdr,
        .free_layout_hdr        = filelayout_free_layout_hdr,
        .alloc_lseg             = filelayout_alloc_lseg,

diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index cae4333..86bcba4 100644 (file)
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -2356,6 +2356,7 @@ static struct pnfs_layoutdriver_type flexfilelayout_type = {
        .name                   = "LAYOUT_FLEX_FILES",
        .owner                  = THIS_MODULE,
        .flags                  = PNFS_LAYOUTGET_ON_OPEN,
+       .max_layoutget_response = 4096, /* 1 page or so... */
        .set_layoutdriver       = ff_layout_set_layoutdriver,
        .alloc_layout_hdr       = ff_layout_alloc_layout_hdr,
        .free_layout_hdr        = ff_layout_free_layout_hdr,

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 6b5b2d3..c5672c0 100644 (file)
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -991,6 +991,7 @@ pnfs_alloc_init_layoutget_args(struct inode *ino,
           gfp_t gfp_flags)
 {
        struct nfs_server *server = pnfs_find_server(ino, ctx);
+       size_t max_reply_sz = server->pnfs_curr_ld->max_layoutget_response;
        size_t max_pages = max_response_pages(server);
        struct nfs4_layoutget *lgp;
 
@@ -1000,6 +1001,12 @@ pnfs_alloc_init_layoutget_args(struct inode *ino,
        if (lgp == NULL)
                return NULL;
 
+       if (max_reply_sz) {
+               size_t npages = (max_reply_sz + PAGE_SIZE - 1) >> PAGE_SHIFT;
+               if (npages < max_pages)
+                       max_pages = npages;
+       }
+
        lgp->args.layout.pages = nfs4_alloc_pages(max_pages, gfp_flags);
        if (!lgp->args.layout.pages) {
                kfree(lgp);

diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index ece367e..e2e9fcd 100644 (file)
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -125,6 +125,7 @@ struct pnfs_layoutdriver_type {
        struct module *owner;
        unsigned flags;
        unsigned max_deviceinfo_size;
+       unsigned max_layoutget_response;
 
        int (*set_layoutdriver) (struct nfs_server *, const struct nfs_fh *);
        int (*clear_layoutdriver) (struct nfs_server *);