This patch adds readpages support in support of readahead when using loose
cache mode. It substantially increases performance for certain workloads.
Signed-off-by: Eric Van Hensbergen <ericvh@xxxxxxxxx>
---
fs/9p/v9fs.c | 2 +-
fs/9p/vfs_addr.c | 98 ++++++++++++++++++++++++++++++++++++++++++----
include/net/9p/client.h | 3 +-
net/9p/client.c | 82 +++++++++++++++++++++++++--------------
4 files changed, 143 insertions(+), 42 deletions(-)
diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index 89ee0ba..ca97404 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -131,7 +131,7 @@ static void v9fs_parse_options(struct v9fs_session_info *v9ses)
char *s, *e;
/* setup defaults */
- v9ses->maxdata = 8192;
+ v9ses->maxdata = (64*1024);
v9ses->afid = ~0;
v9ses->debug = 0;
v9ses->cache = 0;
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index 6248f0e..86c6e0d 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -31,8 +31,11 @@
#include <linux/string.h>
#include <linux/inet.h>
#include <linux/pagemap.h>
+#include <linux/pagevec.h>
#include <linux/idr.h>
#include <linux/sched.h>
+#include <linux/uio.h>
+#include <linux/task_io_accounting_ops.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
@@ -50,31 +53,108 @@
static int v9fs_vfs_readpage(struct file *filp, struct page *page)
{
- int retval;
loff_t offset;
char *buffer;
struct p9_fid *fid;
+ int retval = 0;
+ int total = 0;
+ int count = PAGE_SIZE;
P9_DPRINTK(P9_DEBUG_VFS, "\n");
fid = filp->private_data;
buffer = kmap(page);
offset = page_offset(page);
- retval = p9_client_readn(fid, buffer, offset, PAGE_CACHE_SIZE);
- if (retval < 0)
- goto done;
+ while (count) {
+ struct kvec kv = {buffer+offset, PAGE_SIZE-count};
+ retval = p9_client_readv(fid, &kv, offset, 1);
+ if (retval <= 0)
+ break;
- memset(buffer + retval, 0, PAGE_CACHE_SIZE - retval);
- flush_dcache_page(page);
- SetPageUptodate(page);
- retval = 0;
+ buffer += retval;
+ offset += retval;
+ count -= retval;
+ total += retval;
+ }
+
+ if (retval >= 0) {
+ flush_dcache_page(page);
+ SetPageUptodate(page);
+ retval = 0;
+ }
-done:
kunmap(page);
unlock_page(page);
return retval;
}
+/* large chunks copied and adapted from fs/cifs/file.c */
+static int v9fs_vfs_readpages(struct file *file, struct address_space *mapping,
+ struct list_head *page_list, unsigned num_pages)
+{
+ struct page *tmp_page;
+ loff_t offset;
+ struct pagevec lru_pvec;
+ struct p9_fid *fid;
+ u32 read_size;
+ int retval = 0;
+ unsigned int count = 0;
+ struct list_head *p, *n;
+
+ struct kvec *kv = kmalloc(sizeof(struct kvec)*num_pages, GFP_KERNEL);
+
+ P9_DPRINTK(P9_DEBUG_VFS, "%d pages\n", num_pages);
+
+ if (!kv)
+ return -ENOMEM;
+
+ if (list_empty(page_list))
+ goto free_vec;
+
+ pagevec_init(&lru_pvec, 0);
+
+ fid = file->private_data;
+ tmp_page = list_entry(page_list->prev, struct page, lru);
+ offset = (loff_t)tmp_page->index << PAGE_CACHE_SHIFT;
+
+ list_for_each_entry_reverse(tmp_page, page_list, lru) {
+ BUG_ON(count > num_pages);
+ if (add_to_page_cache(tmp_page, mapping,
+ tmp_page->index, GFP_KERNEL)) {
+ page_cache_release(tmp_page);
+ continue;
+ }
+
+ kv[count].iov_base = kmap(tmp_page);
+ kv[count].iov_len = PAGE_CACHE_SIZE;
+ count++;
+ }
+
+ read_size = count * PAGE_CACHE_SIZE;
+ if (!read_size)
+ goto cleanup;
+
+ retval = p9_client_readv(fid, kv, offset, count);
+
+cleanup:
+ list_for_each_safe(p, n, page_list) {
+ tmp_page = list_entry(p, struct page, lru);
+ list_del(&tmp_page->lru);
+ if (!pagevec_add(&lru_pvec, tmp_page))
+ __pagevec_lru_add(&lru_pvec);
+ kunmap(tmp_page);
+ flush_dcache_page(tmp_page);
+ SetPageUptodate(tmp_page);
+ unlock_page(tmp_page);
+ }
+ pagevec_lru_add(&lru_pvec);
+
+free_vec:
+ kfree(kv);
+ return retval;
+}
+
const struct address_space_operations v9fs_addr_operations = {
.readpage = v9fs_vfs_readpage,
+ .readpages = v9fs_vfs_readpages,
};
diff --git a/include/net/9p/client.h b/include/net/9p/client.h
index 9b9221a..6f17d0a 100644
--- a/include/net/9p/client.h
+++ b/include/net/9p/client.h
@@ -67,8 +67,7 @@ int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, int mode,
char *extension);
int p9_client_clunk(struct p9_fid *fid);
int p9_client_remove(struct p9_fid *fid);
-int p9_client_read(struct p9_fid *fid, char *data, u64 offset, u32 count);
-int p9_client_readn(struct p9_fid *fid, char *data, u64 offset, u32 count);
+int p9_client_readv(struct p9_fid *fid, struct kvec *kv, u64 offset, u32 count);
int p9_client_write(struct p9_fid *fid, char *data, u64 offset, u32 count);
int p9_client_uread(struct p9_fid *fid, char __user *data, u64 offset,
u32 count);
diff --git a/net/9p/client.c b/net/9p/client.c
index d83cc12..0e852e4 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -29,6 +29,7 @@
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
+#include <linux/uio.h>
#include <net/9p/9p.h>
#include <net/9p/transport.h>
#include <net/9p/conn.h>
@@ -455,11 +456,59 @@ done:
}
EXPORT_SYMBOL(p9_client_remove);
-int p9_client_read(struct p9_fid *fid, char *data, u64 offset, u32 count)
+struct kvec_pos {
+ u32 num;
+ u32 offset;
+};
+
+/* fill a kvec from a buffer and zero-fill any extra kvec buffers */
+static void
+fill_kvec(struct kvec *kv, u32 kvc, struct kvec_pos *kp, void *buf, u32 n)
+{
+ int count;
+
+ while (kp->num < kvc) {
+ count = kv[kp->num].iov_len - kp->offset;
+ if (count <= 0) {
+ kp->num++;
+ kp->offset = 0;
+ continue;
+ }
+
+ if (n) {
+ if (count > n)
+ count = n;
+ memmove(kv[kp->num].iov_base+kp->offset, buf, count);
+ n = n - count;
+ } else
+ memset(kv[kp->num].iov_base+kp->offset, 0, count);
+
+ kp->offset += count;
+ if (kp->offset >= kv[kp->num].iov_len) {
+ kp->offset = 0;
+ kp->num++;
+ }
+ }
+}
+
+static size_t kvec_length(const struct kvec *iov, unsigned long nr_segs)
+{
+ unsigned long seg;
+ size_t ret = 0;
+
+ for (seg = 0; seg < nr_segs; seg++)
+ ret += iov[seg].iov_len;
+
+ return ret;
+}
+
+int p9_client_readv(struct p9_fid *fid, struct kvec *kv, u64 offset, u32 kvc)
{
int err, n, rsize, total;
struct p9_fcall *tc, *rc;
struct p9_client *clnt;
+ struct kvec_pos kvp = {0, 0};
+ u32 count = kvec_length(kv, kvc);
P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu %d\n", fid->fid,
(long long unsigned) offset, count);
@@ -491,10 +540,9 @@ int p9_client_read(struct p9_fid *fid, char *data, u64 offset, u32 count)
n = rc->params.rread.count;
if (n > count)
n = count;
+ fill_kvec(kv, kvc, &kvp, rc->params.rread.data, n);
- memmove(data, rc->params.rread.data, n);
count -= n;
- data += n;
offset += n;
total += n;
kfree(tc);
@@ -510,7 +558,7 @@ error:
kfree(rc);
return err;
}
-EXPORT_SYMBOL(p9_client_read);
+EXPORT_SYMBOL(p9_client_readv);
int p9_client_write(struct p9_fid *fid, char *data, u64 offset, u32 count)
{
@@ -683,32 +731,6 @@ error:
}
EXPORT_SYMBOL(p9_client_uwrite);
-int p9_client_readn(struct p9_fid *fid, char *data, u64 offset, u32 count)
-{
- int n, total;
-
- P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu count %d\n", fid->fid,
- (long long unsigned) offset, count);
- n = 0;
- total = 0;
- while (count) {
- n = p9_client_read(fid, data, offset, count);
- if (n <= 0)
- break;
-
- data += n;
- offset += n;
- count -= n;
- total += n;
- }
-
- if (n < 0)
- total = n;
-
- return total;
-}
-EXPORT_SYMBOL(p9_client_readn);
-
struct p9_stat *p9_client_stat(struct p9_fid *fid)
{
int err;
--
1.5.3.rc7
-
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