[PATCH 1/7] readahead: compacting file_ra_state

Fengguang Wu
2007-07-21T04:45:37Z

[-- Attachment #1: short-rasize.patch --]
[-- Type: text/plain, Size: 2010 bytes --]

Use 'unsigned int' instead of 'unsigned long' for readahead sizes.

This helps reduce memory consumption on 64bit CPU when
a lot of files are opened.

CC: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn>
---
include/linux/fs.h | 8 ++++----
mm/filemap.c | 2 +-
mm/readahead.c | 2 +-
3 files changed, 6 insertions(+), 6 deletions(-)

--- linux-2.6.22-rc6-mm1.orig/include/linux/fs.h
+++ linux-2.6.22-rc6-mm1/include/linux/fs.h
@@ -771,12 +771,12 @@ struct fown_struct {
* Track a single file's readahead state
*/
struct file_ra_state {
- pgoff_t start; /* where readahead started */
- unsigned long size; /* # of readahead pages */
- unsigned long async_size; /* do asynchronous readahead when
+ pgoff_t start; /* where readahead started */
+ unsigned int size; /* # of readahead pages */
+ unsigned int async_size; /* do asynchronous readahead when
there are only # of pages ahead */

- unsigned long ra_pages; /* Maximum readahead window */
+ unsigned int ra_pages; /* Maximum readahead window */
unsigned long mmap_hit; /* Cache hit stat for mmap accesses */
unsigned long mmap_miss; /* Cache miss stat for mmap accesses */
unsigned long prev_index; /* Cache last read() position */
--- linux-2.6.22-rc6-mm1.orig/mm/filemap.c
+++ linux-2.6.22-rc6-mm1/mm/filemap.c
@@ -840,7 +840,7 @@ static void shrink_readahead_size_eio(st
if (count > 5)
return;
count++;
- printk(KERN_WARNING "Reducing readahead size to %luK\n",
+ printk(KERN_WARNING "Reducing readahead size to %dK\n",
ra->ra_pages << (PAGE_CACHE_SHIFT - 10));
}

--- linux-2.6.22-rc6-mm1.orig/mm/readahead.c
+++ linux-2.6.22-rc6-mm1/mm/readahead.c
@@ -342,7 +342,7 @@ ondemand_readahead(struct address_space
bool hit_readahead_marker, pgoff_t offset,
unsigned long req_size)
{
- unsigned long max; /* max readahead pages */
+ int max; /* max readahead pages */
int sequential;

max = ra->ra_pages;

--