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NFS: readdir with vmapped pages

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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>
This commit is contained in:
Bryan Schumaker
2010-10-20 15:44:37 -04:00
committed by Trond Myklebust
parent afa8ccc978
commit 56e4ebf877
7 changed files with 71 additions and 23 deletions
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66
fs/nfs/dir.c
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@@ -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 @@ out:
/* 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 @@ int nfs_readdir_xdr_filler(struct page *xdr_page, nfs_readdir_descriptor_t *desc
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 @@ out:
/* 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 @@ void nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *e
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 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
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: