lkml.org 
[lkml]   [2007]   [Apr]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC 7/8] Enhance ramfs to support higher order pages
Date
Variable Order Page Cache: Add support to ramfs

The simplest file system to use is ramfs. Add a mount parameter that
specifies the page order of the pages that ramfs should use. If the
order is greater than zero then disable mmap functionality.

This could be removed if the VM would be changes to support faulting
higher order pages but for now we are content with buffered I/O on higher
order pages.

Signed-off-by: Christoph Lameter <clameter@sgi.com>

---
fs/ramfs/file-mmu.c | 11 +++++++++++
fs/ramfs/inode.c | 15 ++++++++++++---
include/linux/ramfs.h | 1 +
3 files changed, 24 insertions(+), 3 deletions(-)

Index: linux-2.6.21-rc7/fs/ramfs/file-mmu.c
===================================================================
--- linux-2.6.21-rc7.orig/fs/ramfs/file-mmu.c 2007-04-18 21:46:38.000000000 -0700
+++ linux-2.6.21-rc7/fs/ramfs/file-mmu.c 2007-04-18 22:02:03.000000000 -0700
@@ -45,6 +45,17 @@ const struct file_operations ramfs_file_
.llseek = generic_file_llseek,
};

+/* Higher order mappings do not support mmmap */
+const struct file_operations ramfs_file_higher_order_operations = {
+ .read = do_sync_read,
+ .aio_read = generic_file_aio_read,
+ .write = do_sync_write,
+ .aio_write = generic_file_aio_write,
+ .fsync = simple_sync_file,
+ .sendfile = generic_file_sendfile,
+ .llseek = generic_file_llseek,
+};
+
const struct inode_operations ramfs_file_inode_operations = {
.getattr = simple_getattr,
};
Index: linux-2.6.21-rc7/fs/ramfs/inode.c
===================================================================
--- linux-2.6.21-rc7.orig/fs/ramfs/inode.c 2007-04-18 21:46:38.000000000 -0700
+++ linux-2.6.21-rc7/fs/ramfs/inode.c 2007-04-18 22:02:03.000000000 -0700
@@ -61,6 +61,7 @@ struct inode *ramfs_get_inode(struct sup
inode->i_blocks = 0;
inode->i_mapping->a_ops = &ramfs_aops;
inode->i_mapping->backing_dev_info = &ramfs_backing_dev_info;
+ inode->i_mapping->order = sb->s_blocksize_bits - PAGE_CACHE_SHIFT;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
switch (mode & S_IFMT) {
default:
@@ -68,7 +69,10 @@ struct inode *ramfs_get_inode(struct sup
break;
case S_IFREG:
inode->i_op = &ramfs_file_inode_operations;
- inode->i_fop = &ramfs_file_operations;
+ if (inode->i_mapping->order)
+ inode->i_fop = &ramfs_file_higher_order_operations;
+ else
+ inode->i_fop = &ramfs_file_operations;
break;
case S_IFDIR:
inode->i_op = &ramfs_dir_inode_operations;
@@ -164,10 +168,15 @@ static int ramfs_fill_super(struct super
{
struct inode * inode;
struct dentry * root;
+ int order = 0;
+ char *options = data;
+
+ if (options && *options)
+ order = simple_strtoul(options, NULL, 10);

sb->s_maxbytes = MAX_LFS_FILESIZE;
- sb->s_blocksize = PAGE_CACHE_SIZE;
- sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+ sb->s_blocksize = PAGE_CACHE_SIZE << order;
+ sb->s_blocksize_bits = order + PAGE_CACHE_SHIFT;
sb->s_magic = RAMFS_MAGIC;
sb->s_op = &ramfs_ops;
sb->s_time_gran = 1;
Index: linux-2.6.21-rc7/include/linux/ramfs.h
===================================================================
--- linux-2.6.21-rc7.orig/include/linux/ramfs.h 2007-04-18 21:46:38.000000000 -0700
+++ linux-2.6.21-rc7/include/linux/ramfs.h 2007-04-18 22:02:03.000000000 -0700
@@ -16,6 +16,7 @@ extern int ramfs_nommu_mmap(struct file
#endif

extern const struct file_operations ramfs_file_operations;
+extern const struct file_operations ramfs_file_higher_order_operations;
extern struct vm_operations_struct generic_file_vm_ops;
extern int __init init_rootfs(void);

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
\
 
 \ /
  Last update: 2007-04-19 18:39    [W:0.210 / U:0.576 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site