andrew morton suggested there are places in the NFS client that could make
use of kmap_atomic instead of vanilla kmap in order to improve scalability
on 8-way and higher SMP systems.
against 2.5.48.
diff -ruN 00-stock/fs/nfs/dir.c 01-kmap_atomic/fs/nfs/dir.c
--- 00-stock/fs/nfs/dir.c Sun Nov 17 23:29:45 2002
+++ 01-kmap_atomic/fs/nfs/dir.c Mon Nov 18 11:43:24 2002
@@ -208,7 +208,7 @@
/* NOTE: Someone else may have changed the READDIRPLUS flag */
desc->page = page;
- desc->ptr = kmap(page);
+ desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */
status = find_dirent(desc, page);
if (status < 0)
dir_page_release(desc);
@@ -345,7 +345,7 @@
NFS_SERVER(inode)->dtsize,
desc->plus);
desc->page = page;
- desc->ptr = kmap(page);
+ desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */
if (desc->error >= 0) {
if ((status = dir_decode(desc)) == 0)
desc->entry->prev_cookie = desc->target;
@@ -717,9 +717,9 @@
res = -EIO;
if (PageUptodate(page)) {
- desc.ptr = kmap(page);
+ desc.ptr = kmap_atomic(page, KM_USER0);
res = find_dirent_name(&desc, page, dentry);
- kunmap(page);
+ kunmap_atomic(desc.ptr, KM_USER0);
}
page_cache_release(page);
diff -ruN 00-stock/fs/nfs/nfs2xdr.c 01-kmap_atomic/fs/nfs/nfs2xdr.c
--- 00-stock/fs/nfs/nfs2xdr.c Sun Nov 17 23:29:31 2002
+++ 01-kmap_atomic/fs/nfs/nfs2xdr.c Mon Nov 18 11:43:24 2002
@@ -370,7 +370,7 @@
int hdrlen, recvd;
int status, nr;
unsigned int len, pglen;
- u32 *end, *entry;
+ u32 *end, *entry, *kaddr;
if ((status = ntohl(*p++)))
return -nfs_stat_to_errno(status);
@@ -390,7 +390,7 @@
if (pglen > recvd)
pglen = recvd;
page = rcvbuf->pages;
- p = kmap(*page);
+ kaddr = p = (u32 *)kmap_atomic(*page, KM_USER0);
end = (u32 *)((char *)p + pglen);
entry = p;
for (nr = 0; *p++; nr++) {
@@ -411,7 +411,7 @@
if (!nr && (entry[0] != 0 || entry[1] == 0))
goto short_pkt;
out:
- kunmap(*page);
+ kunmap_atomic(kaddr, KM_USER0);
return nr;
short_pkt:
entry[0] = entry[1] = 0;
@@ -422,8 +422,8 @@
}
goto out;
err_unmap:
- kunmap(*page);
- return -errno_NFSERR_IO;
+ nr = -errno_NFSERR_IO;
+ goto out;
}
u32 *
@@ -534,7 +534,7 @@
xdr_shift_buf(rcvbuf, iov->iov_len - hdrlen);
}
- strlen = (u32*)kmap(rcvbuf->pages[0]);
+ strlen = (u32*)kmap_atomic(rcvbuf->pages[0], KM_USER0);
/* Convert length of symlink */
len = ntohl(*strlen);
if (len > rcvbuf->page_len)
@@ -543,7 +543,7 @@
/* NULL terminate the string we got */
string = (char *)(strlen + 1);
string[len] = 0;
- kunmap(rcvbuf->pages[0]);
+ kunmap_atomic(strlen, KM_USER0);
return 0;
}
diff -ruN 00-stock/fs/nfs/nfs3xdr.c 01-kmap_atomic/fs/nfs/nfs3xdr.c
--- 00-stock/fs/nfs/nfs3xdr.c Sun Nov 17 23:29:58 2002
+++ 01-kmap_atomic/fs/nfs/nfs3xdr.c Mon Nov 18 11:43:24 2002
@@ -496,7 +496,7 @@
int hdrlen, recvd;
int status, nr;
unsigned int len, pglen;
- u32 *entry, *end;
+ u32 *entry, *end, *kaddr;
status = ntohl(*p++);
/* Decode post_op_attrs */
@@ -526,7 +526,7 @@
if (pglen > recvd)
pglen = recvd;
page = rcvbuf->pages;
- p = kmap(*page);
+ kaddr = p = (u32 *)kmap_atomic(*page, KM_USER0);
end = (u32 *)((char *)p + pglen);
entry = p;
for (nr = 0; *p++; nr++) {
@@ -571,7 +571,7 @@
if (!nr && (entry[0] != 0 || entry[1] == 0))
goto short_pkt;
out:
- kunmap(*page);
+ kunmap_atomic(kaddr, KM_USER0);
return nr;
short_pkt:
entry[0] = entry[1] = 0;
@@ -582,8 +582,8 @@
}
goto out;
err_unmap:
- kunmap(*page);
- return -errno_NFSERR_IO;
+ nr = -errno_NFSERR_IO;
+ goto out;
}
u32 *
@@ -746,7 +746,7 @@
xdr_shift_buf(rcvbuf, iov->iov_len - hdrlen);
}
- strlen = (u32*)kmap(rcvbuf->pages[0]);
+ strlen = (u32*)kmap_atomic(rcvbuf->pages[0], KM_USER0);
/* Convert length of symlink */
len = ntohl(*strlen);
if (len > rcvbuf->page_len)
@@ -755,7 +755,7 @@
/* NULL terminate the string we got */
string = (char *)(strlen + 1);
string[len] = 0;
- kunmap(rcvbuf->pages[0]);
+ kunmap_atomic(strlen, KM_USER0);
return 0;
}
diff -ruN 00-stock/fs/nfs/nfs4proc.c 01-kmap_atomic/fs/nfs/nfs4proc.c
--- 00-stock/fs/nfs/nfs4proc.c Sun Nov 17 23:29:51 2002
+++ 01-kmap_atomic/fs/nfs/nfs4proc.c Mon Nov 18 11:43:24 2002
@@ -451,7 +451,7 @@
* when talking to the server, we always send cookie 0
* instead of 1 or 2.
*/
- start = p = (u32 *)kmap(*pages);
+ start = p = (u32 *)kmap_atomic(*pages, KM_USER0);
if (cookie == 0) {
*p++ = xdr_one; /* next */
@@ -479,7 +479,7 @@
readdir->rd_pgbase = (char *)p - (char *)start;
readdir->rd_count -= readdir->rd_pgbase;
- kunmap(*pages);
+ kunmap_atomic(start, KM_USER0);
}
static void
diff -ruN 00-stock/fs/nfs/nfs4xdr.c 01-kmap_atomic/fs/nfs/nfs4xdr.c
--- 00-stock/fs/nfs/nfs4xdr.c Sun Nov 17 23:29:57 2002
+++ 01-kmap_atomic/fs/nfs/nfs4xdr.c Mon Nov 18 11:43:25 2002
@@ -1349,7 +1349,7 @@
struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
struct page *page = *rcvbuf->pages;
unsigned int pglen = rcvbuf->page_len;
- u32 *end, *entry;
+ u32 *end, *entry, *kaddr;
u32 len, attrlen, word;
int i;
DECODE_HEAD;
@@ -1359,7 +1359,7 @@
COPYMEM(readdir->rd_resp_verifier, 8);
BUG_ON(pglen > PAGE_CACHE_SIZE);
- p = (u32 *) kmap(page);
+ kaddr = p = (u32 *) kmap_atomic(page, KM_USER0);
end = (u32 *) ((char *)p + pglen + readdir->rd_pgbase);
while (*p++) {
@@ -1403,18 +1403,18 @@
if (p + 1 > end)
goto short_pkt;
}
- kunmap(page);
+ kunmap_atomic(kaddr, KM_USER0);
}
DECODE_TAIL;
short_pkt:
printk(KERN_NOTICE "NFS: short packet in readdir reply!\n");
/* truncate listing */
- kunmap(page);
+ kunmap_atomic(kaddr, KM_USER0);
entry[0] = entry[1] = 0;
return 0;
err_unmap:
- kunmap(page);
+ kunmap_atomic(kaddr, KM_USER0);
return -errno_NFSERR_IO;
}
@@ -1434,18 +1434,18 @@
* and and null-terminate the text (the VFS expects
* null-termination).
*/
- strlen = (u32 *) kmap(rcvbuf->pages[0]);
+ strlen = (u32 *) kmap_atomic(rcvbuf->pages[0], KM_USER0);
len = ntohl(*strlen);
if (len > PAGE_CACHE_SIZE - 5) {
printk(KERN_WARNING "nfs: server returned giant symlink!\n");
- kunmap(rcvbuf->pages[0]);
+ kunmap_atomic(strlen, KM_USER0);
return -EIO;
}
*strlen = len;
string = (char *)(strlen + 1);
string[len] = '\0';
- kunmap(rcvbuf->pages[0]);
+ kunmap_atomic(strlen, KM_USER0);
}
return 0;
}
diff -ruN 00-stock/fs/nfs/read.c 01-kmap_atomic/fs/nfs/read.c
--- 00-stock/fs/nfs/read.c Sun Nov 17 23:29:20 2002
+++ 01-kmap_atomic/fs/nfs/read.c Mon Nov 18 11:43:25 2002
@@ -118,12 +118,8 @@
break;
} while (count);
- if (count) {
- char *kaddr = kmap(page);
- memset(kaddr + offset, 0, count);
- kunmap(page);
- }
- flush_dcache_page(page);
+ if (count)
+ memclear_highpage_flush(page, offset, count);
SetPageUptodate(page);
if (PageError(page))
ClearPageError(page);
@@ -272,12 +268,9 @@
if (task->tk_status >= 0) {
if (count < PAGE_CACHE_SIZE) {
- char *p = kmap(page);
-
- if (count < req->wb_bytes)
- memset(p + req->wb_offset + count, 0,
+ memclear_highpage_flush(page,
+ req->wb_offset + count,
req->wb_bytes - count);
- kunmap(page);
if (eof ||
((fattr->valid & NFS_ATTR_FATTR) &&
@@ -293,7 +286,6 @@
}
} else
SetPageError(page);
- flush_dcache_page(page);
unlock_page(page);
dprintk("NFS: read (%s/%Ld %d@%Ld)\n",
diff -ruN 00-stock/net/sunrpc/xdr.c 01-kmap_atomic/net/sunrpc/xdr.c
--- 00-stock/net/sunrpc/xdr.c Sun Nov 17 23:29:50 2002
+++ 01-kmap_atomic/net/sunrpc/xdr.c Mon Nov 18 11:43:25 2002
@@ -307,6 +307,7 @@
len = pglen;
ret = copy_actor(desc, kaddr, len);
}
+ flush_dcache_page(*ppage);
kunmap_atomic(kaddr, KM_SKB_SUNRPC_DATA);
if (ret != len || !desc->count)
return;