提交 bcb71bba 编写于 作者: T Trond Myklebust

NFS: Another cleanup of the read/write request coalescing code

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
上级 d8a5ad75
......@@ -225,14 +225,26 @@ nfs_wait_on_request(struct nfs_page *req)
/**
* nfs_pageio_init - initialise a page io descriptor
* @desc: pointer to descriptor
* @iosize: io block size
* @inode: pointer to inode
* @doio: pointer to io function
* @bsize: io block size
* @io_flags: extra parameters for the io function
*/
void nfs_pageio_init(struct nfs_pageio_descriptor *desc, unsigned int bsize)
void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
struct inode *inode,
int (*doio)(struct inode *, struct list_head *, size_t, int),
unsigned int bsize,
int io_flags)
{
INIT_LIST_HEAD(&desc->pg_list);
desc->pg_bytes_written = 0;
desc->pg_count = 0;
desc->pg_bsize = bsize;
desc->pg_base = 0;
desc->pg_inode = inode;
desc->pg_doio = doio;
desc->pg_ioflags = io_flags;
desc->pg_error = 0;
}
/**
......@@ -265,14 +277,14 @@ static int nfs_can_coalesce_requests(struct nfs_page *prev,
}
/**
* nfs_pageio_add_request - Attempt to coalesce a request into a page list.
* nfs_pageio_do_add_request - Attempt to coalesce a request into a page list.
* @desc: destination io descriptor
* @req: request
*
* Returns true if the request 'req' was successfully coalesced into the
* existing list of pages 'desc'.
*/
static int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
struct nfs_page *req)
{
size_t newlen = req->wb_bytes;
......@@ -301,6 +313,46 @@ static int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
return 1;
}
/*
* Helper for nfs_pageio_add_request and nfs_pageio_complete
*/
static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc)
{
if (!list_empty(&desc->pg_list)) {
int error = desc->pg_doio(desc->pg_inode,
&desc->pg_list,
desc->pg_count,
desc->pg_ioflags);
if (error < 0)
desc->pg_error = error;
else
desc->pg_bytes_written += desc->pg_count;
}
if (list_empty(&desc->pg_list)) {
desc->pg_count = 0;
desc->pg_base = 0;
}
}
/**
* nfs_pageio_add_request - Attempt to coalesce a request into a page list.
* @desc: destination io descriptor
* @req: request
*
* Returns true if the request 'req' was successfully coalesced into the
* existing list of pages 'desc'.
*/
static int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
struct nfs_page *req)
{
while (!nfs_pageio_do_add_request(desc, req)) {
nfs_pageio_doio(desc);
if (desc->pg_error < 0)
return 0;
}
return 1;
}
/**
* nfs_pageio_add_list - Split coalesced requests out from a list.
* @desc: destination io descriptor
......@@ -320,6 +372,15 @@ void nfs_pageio_add_list(struct nfs_pageio_descriptor *desc,
}
}
/**
* nfs_pageio_complete - Complete I/O on an nfs_pageio_descriptor
* @desc: pointer to io descriptor
*/
void nfs_pageio_complete(struct nfs_pageio_descriptor *desc)
{
nfs_pageio_doio(desc);
}
#define NFS_SCAN_MAXENTRIES 16
/**
* nfs_scan_dirty - Scan the radix tree for dirty requests
......
......@@ -27,7 +27,8 @@
#define NFSDBG_FACILITY NFSDBG_PAGECACHE
static int nfs_pagein_one(struct list_head *, struct inode *);
static int nfs_pagein_multi(struct inode *, struct list_head *, size_t, int);
static int nfs_pagein_one(struct inode *, struct list_head *, size_t, int);
static const struct rpc_call_ops nfs_read_partial_ops;
static const struct rpc_call_ops nfs_read_full_ops;
......@@ -133,7 +134,10 @@ static int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
memclear_highpage_flush(page, len, PAGE_CACHE_SIZE - len);
nfs_list_add_request(new, &one_request);
nfs_pagein_one(&one_request, inode);
if (NFS_SERVER(inode)->rsize < PAGE_CACHE_SIZE)
nfs_pagein_multi(inode, &one_request, len, 0);
else
nfs_pagein_one(inode, &one_request, len, 0);
return 0;
}
......@@ -230,7 +234,7 @@ static void nfs_execute_read(struct nfs_read_data *data)
* won't see the new data until our attribute cache is updated. This is more
* or less conventional NFS client behavior.
*/
static int nfs_pagein_multi(struct list_head *head, struct inode *inode)
static int nfs_pagein_multi(struct inode *inode, struct list_head *head, size_t count, int flags)
{
struct nfs_page *req = nfs_list_entry(head->next);
struct page *page = req->wb_page;
......@@ -242,7 +246,7 @@ static int nfs_pagein_multi(struct list_head *head, struct inode *inode)
nfs_list_remove_request(req);
nbytes = req->wb_bytes;
nbytes = count;
do {
size_t len = min(nbytes,rsize);
......@@ -258,23 +262,19 @@ static int nfs_pagein_multi(struct list_head *head, struct inode *inode)
ClearPageError(page);
offset = 0;
nbytes = req->wb_bytes;
nbytes = count;
do {
data = list_entry(list.next, struct nfs_read_data, pages);
list_del_init(&data->pages);
data->pagevec[0] = page;
if (nbytes > rsize) {
if (nbytes < rsize)
rsize = nbytes;
nfs_read_rpcsetup(req, data, &nfs_read_partial_ops,
rsize, offset);
offset += rsize;
nbytes -= rsize;
} else {
nfs_read_rpcsetup(req, data, &nfs_read_partial_ops,
nbytes, offset);
nbytes = 0;
}
nfs_execute_read(data);
} while (nbytes != 0);
......@@ -291,30 +291,24 @@ static int nfs_pagein_multi(struct list_head *head, struct inode *inode)
return -ENOMEM;
}
static int nfs_pagein_one(struct list_head *head, struct inode *inode)
static int nfs_pagein_one(struct inode *inode, struct list_head *head, size_t count, int flags)
{
struct nfs_page *req;
struct page **pages;
struct nfs_read_data *data;
unsigned int count;
if (NFS_SERVER(inode)->rsize < PAGE_CACHE_SIZE)
return nfs_pagein_multi(head, inode);
data = nfs_readdata_alloc(NFS_SERVER(inode)->rsize);
data = nfs_readdata_alloc(count);
if (!data)
goto out_bad;
INIT_LIST_HEAD(&data->pages);
pages = data->pagevec;
count = 0;
while (!list_empty(head)) {
req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
nfs_list_add_request(req, &data->pages);
ClearPageError(req->wb_page);
*pages++ = req->wb_page;
count += req->wb_bytes;
}
req = nfs_list_entry(data->pages.next);
......@@ -328,22 +322,20 @@ static int nfs_pagein_one(struct list_head *head, struct inode *inode)
}
static int
nfs_pagein_list(struct list_head *head, unsigned int rsize)
nfs_pagein_list(struct inode *inode, struct list_head *head, unsigned int rsize)
{
struct nfs_pageio_descriptor desc;
struct nfs_page *req;
unsigned int pages = 0;
int error = 0;
while (!list_empty(head)) {
nfs_pageio_init(&desc, rsize);
if (rsize < PAGE_CACHE_SIZE)
nfs_pageio_init(&desc, inode, nfs_pagein_multi, rsize, 0);
else
nfs_pageio_init(&desc, inode, nfs_pagein_one, rsize, 0);
nfs_pageio_add_list(&desc, head);
req = nfs_list_entry(desc.pg_list.next);
error = nfs_pagein_one(&desc.pg_list, req->wb_context->dentry->d_inode);
if (error < 0)
break;
pages += (desc.pg_count + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
}
nfs_pageio_complete(&desc);
pages += (desc.pg_bytes_written + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
nfs_async_read_error(head);
if (error >= 0)
......@@ -597,7 +589,7 @@ int nfs_readpages(struct file *filp, struct address_space *mapping,
filp->private_data);
ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
if (!list_empty(&head)) {
int err = nfs_pagein_list(&head, server->rsize);
int err = nfs_pagein_list(inode, &head, server->rsize);
if (!ret)
nfs_add_stats(inode, NFSIOS_READPAGES, err);
ret = err;
......
......@@ -835,7 +835,7 @@ static void nfs_execute_write(struct nfs_write_data *data)
* Generate multiple small requests to write out a single
* contiguous dirty area on one page.
*/
static int nfs_flush_multi(struct inode *inode, struct list_head *head, int how)
static int nfs_flush_multi(struct inode *inode, struct list_head *head, size_t count, int how)
{
struct nfs_page *req = nfs_list_entry(head->next);
struct page *page = req->wb_page;
......@@ -847,7 +847,7 @@ static int nfs_flush_multi(struct inode *inode, struct list_head *head, int how)
nfs_list_remove_request(req);
nbytes = req->wb_bytes;
nbytes = count;
do {
size_t len = min(nbytes, wsize);
......@@ -862,23 +862,19 @@ static int nfs_flush_multi(struct inode *inode, struct list_head *head, int how)
ClearPageError(page);
offset = 0;
nbytes = req->wb_bytes;
nbytes = count;
do {
data = list_entry(list.next, struct nfs_write_data, pages);
list_del_init(&data->pages);
data->pagevec[0] = page;
if (nbytes > wsize) {
if (nbytes < wsize)
wsize = nbytes;
nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
wsize, offset, how);
offset += wsize;
nbytes -= wsize;
} else {
nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
nbytes, offset, how);
nbytes = 0;
}
nfs_execute_write(data);
} while (nbytes != 0);
......@@ -904,26 +900,23 @@ static int nfs_flush_multi(struct inode *inode, struct list_head *head, int how)
* This is the case if nfs_updatepage detects a conflicting request
* that has been written but not committed.
*/
static int nfs_flush_one(struct inode *inode, struct list_head *head, int how)
static int nfs_flush_one(struct inode *inode, struct list_head *head, size_t count, int how)
{
struct nfs_page *req;
struct page **pages;
struct nfs_write_data *data;
unsigned int count;
data = nfs_writedata_alloc(NFS_SERVER(inode)->wsize);
data = nfs_writedata_alloc(count);
if (!data)
goto out_bad;
pages = data->pagevec;
count = 0;
while (!list_empty(head)) {
req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
nfs_list_add_request(req, &data->pages);
ClearPageError(req->wb_page);
*pages++ = req->wb_page;
count += req->wb_bytes;
}
req = nfs_list_entry(data->pages.next);
......@@ -946,28 +939,22 @@ static int nfs_flush_one(struct inode *inode, struct list_head *head, int how)
static int nfs_flush_list(struct inode *inode, struct list_head *head, int npages, int how)
{
struct nfs_pageio_descriptor desc;
int (*flush_one)(struct inode *, struct list_head *, int);
int wpages = NFS_SERVER(inode)->wpages;
int wsize = NFS_SERVER(inode)->wsize;
int error;
flush_one = nfs_flush_one;
if (wsize < PAGE_CACHE_SIZE)
flush_one = nfs_flush_multi;
/* For single writes, FLUSH_STABLE is more efficient */
if (npages <= wpages && npages == NFS_I(inode)->npages
&& nfs_list_entry(head->next)->wb_bytes <= wsize)
how |= FLUSH_STABLE;
do {
nfs_pageio_init(&desc, wsize);
if (wsize < PAGE_CACHE_SIZE)
nfs_pageio_init(&desc, inode, nfs_flush_multi, wsize, how);
else
nfs_pageio_init(&desc, inode, nfs_flush_one, wsize, how);
nfs_pageio_add_list(&desc, head);
error = flush_one(inode, &desc.pg_list, how);
if (error < 0)
goto out_err;
} while (!list_empty(head));
nfs_pageio_complete(&desc);
if (desc.pg_error == 0)
return 0;
out_err:
while (!list_empty(head)) {
struct nfs_page *req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
......@@ -975,7 +962,7 @@ static int nfs_flush_list(struct inode *inode, struct list_head *head, int npage
nfs_end_page_writeback(req->wb_page);
nfs_clear_page_writeback(req);
}
return error;
return desc.pg_error;
}
/*
......
......@@ -50,9 +50,15 @@ struct nfs_page {
struct nfs_pageio_descriptor {
struct list_head pg_list;
unsigned long pg_bytes_written;
size_t pg_count;
size_t pg_bsize;
unsigned int pg_base;
struct inode *pg_inode;
int (*pg_doio)(struct inode *, struct list_head *, size_t, int);
int pg_ioflags;
int pg_error;
};
#define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
......@@ -72,9 +78,13 @@ extern long nfs_scan_dirty(struct address_space *mapping,
extern int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head, struct list_head *dst,
unsigned long idx_start, unsigned int npages);
extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
size_t iosize);
struct inode *inode,
int (*doio)(struct inode *, struct list_head *, size_t, int),
size_t bsize,
int how);
extern void nfs_pageio_add_list(struct nfs_pageio_descriptor *,
struct list_head *);
extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
extern int nfs_wait_on_request(struct nfs_page *);
extern void nfs_unlock_request(struct nfs_page *req);
extern int nfs_set_page_writeback_locked(struct nfs_page *req);
......
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