From: Trond Myklebust Date: Tue, 22 Jan 2008 17:13:06 -0500 NFS: Optimise nfs_vm_page_mkwrite() The current model locks the page twice for no good reason. Optimise by inlining the parts of nfs_write_begin()/nfs_write_end() that we care about. Signed-off-by: Trond Myklebust --- fs/nfs/file.c | 36 ++++++++++++++---------------------- 1 files changed, 14 insertions(+), 22 deletions(-) diff --git a/fs/nfs/file.c b/fs/nfs/file.c index b3bb89f..4560fc2 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -392,35 +392,27 @@ static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct page *page) struct file *filp = vma->vm_file; unsigned pagelen; int ret = -EINVAL; - void *fsdata; struct address_space *mapping; - loff_t offset; lock_page(page); mapping = page->mapping; - if (mapping != vma->vm_file->f_path.dentry->d_inode->i_mapping) { - unlock_page(page); - return -EINVAL; - } + if (mapping != vma->vm_file->f_path.dentry->d_inode->i_mapping) + goto out_unlock; + + ret = 0; pagelen = nfs_page_length(page); - offset = (loff_t)page->index << PAGE_CACHE_SHIFT; - unlock_page(page); + if (pagelen == 0) + goto out_unlock; - /* - * we can use mapping after releasing the page lock, because: - * we hold mmap_sem on the fault path, which should pin the vma - * which should pin the file, which pins the dentry which should - * hold a reference on inode. - */ + ret = nfs_flush_incompatible(filp, page); + if (ret != 0) + goto out_unlock; - if (pagelen) { - struct page *page2 = NULL; - ret = nfs_write_begin(filp, mapping, offset, pagelen, - 0, &page2, &fsdata); - if (!ret) - ret = nfs_write_end(filp, mapping, offset, pagelen, - pagelen, page2, fsdata); - } + ret = nfs_updatepage(filp, page, 0, pagelen); + if (ret == 0) + ret = pagelen; +out_unlock: + unlock_page(page); return ret; }