From: Chuck Lever Subject: [PATCH] use kmap_atomic instaed of kmap in NFS client Date: Mon, 18 Nov 2002 16:50:40 -0500 (EST) Sender: linux-kernel-owner@vger.kernel.org Message-ID: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Linux Kernel Mailing List , Linux NFS List Return-path: To: Linus Torvalds List-ID: 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;