NFS: readdir with vmapped pages
We can use vmapped pages to read more information from the network at once.
This will reduce the number of calls needed to complete a readdir.
Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
[trondmy: Added #include for linux/vmalloc.h> in fs/nfs/dir.c]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 88cbcda..5d7da3a 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -33,6 +33,7 @@
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/sched.h>
+#include <linux/vmalloc.h>
#include "delegation.h"
#include "iostat.h"
@@ -327,7 +328,7 @@
/* Fill a page with xdr information before transferring to the cache page */
static
-int nfs_readdir_xdr_filler(struct page *xdr_page, nfs_readdir_descriptor_t *desc,
+int nfs_readdir_xdr_filler(struct page **pages, nfs_readdir_descriptor_t *desc,
struct nfs_entry *entry, struct file *file, struct inode *inode)
{
struct rpc_cred *cred = nfs_file_cred(file);
@@ -337,7 +338,7 @@
again:
timestamp = jiffies;
gencount = nfs_inc_attr_generation_counter();
- error = NFS_PROTO(inode)->readdir(file->f_path.dentry, cred, entry->cookie, xdr_page,
+ error = NFS_PROTO(inode)->readdir(file->f_path.dentry, cred, entry->cookie, pages,
NFS_SERVER(inode)->dtsize, desc->plus);
if (error < 0) {
/* We requested READDIRPLUS, but the server doesn't grok it */
@@ -436,11 +437,11 @@
/* Perform conversion from xdr to cache array */
static
void nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry,
- struct page *xdr_page, struct page *page, unsigned int buflen)
+ void *xdr_page, struct page *page, unsigned int buflen)
{
struct xdr_stream stream;
struct xdr_buf buf;
- __be32 *ptr = kmap(xdr_page);
+ __be32 *ptr = xdr_page;
buf.head->iov_base = xdr_page;
buf.head->iov_len = buflen;
@@ -458,18 +459,59 @@
if (desc->plus == 1)
nfs_prime_dcache(desc->file->f_path.dentry, entry);
}
- kunmap(xdr_page);
+}
+
+static
+void nfs_readdir_free_pagearray(struct page **pages, unsigned int npages)
+{
+ unsigned int i;
+ for (i = 0; i < npages; i++)
+ put_page(pages[i]);
+}
+
+static
+void nfs_readdir_free_large_page(void *ptr, struct page **pages,
+ unsigned int npages)
+{
+ vm_unmap_ram(ptr, npages);
+ nfs_readdir_free_pagearray(pages, npages);
+}
+
+/*
+ * nfs_readdir_large_page will allocate pages that must be freed with a call
+ * to nfs_readdir_free_large_page
+ */
+static
+void *nfs_readdir_large_page(struct page **pages, unsigned int npages)
+{
+ void *ptr;
+ unsigned int i;
+
+ for (i = 0; i < npages; i++) {
+ struct page *page = alloc_page(GFP_KERNEL);
+ if (page == NULL)
+ goto out_freepages;
+ pages[i] = page;
+ }
+
+ ptr = vm_map_ram(pages, NFS_MAX_READDIR_PAGES, 0, PAGE_KERNEL);
+ if (!IS_ERR_OR_NULL(ptr))
+ return ptr;
+out_freepages:
+ nfs_readdir_free_pagearray(pages, i);
+ return NULL;
}
static
int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page, struct inode *inode)
{
- struct page *xdr_page;
+ struct page *pages[NFS_MAX_READDIR_PAGES];
+ void *pages_ptr = NULL;
struct nfs_entry entry;
struct file *file = desc->file;
struct nfs_cache_array *array;
int status = 0;
- unsigned int array_size = 1;
+ unsigned int array_size = ARRAY_SIZE(pages);
entry.prev_cookie = 0;
entry.cookie = *desc->dir_cookie;
@@ -483,18 +525,18 @@
memset(array, 0, sizeof(struct nfs_cache_array));
array->eof_index = -1;
- xdr_page = alloc_page(GFP_KERNEL);
- if (!xdr_page)
+ pages_ptr = nfs_readdir_large_page(pages, array_size);
+ if (!pages_ptr)
goto out_release_array;
do {
- status = nfs_readdir_xdr_filler(xdr_page, desc, &entry, file, inode);
+ status = nfs_readdir_xdr_filler(pages, desc, &entry, file, inode);
if (status < 0)
break;
- nfs_readdir_page_filler(desc, &entry, xdr_page, page, array_size * PAGE_SIZE);
+ nfs_readdir_page_filler(desc, &entry, pages_ptr, page, array_size * PAGE_SIZE);
} while (array->eof_index < 0 && array->size < MAX_READDIR_ARRAY);
- put_page(xdr_page);
+ nfs_readdir_free_large_page(pages_ptr, pages, array_size);
out_release_array:
nfs_readdir_release_array(page);
out: