[patch] smarter atime updates

Andrew Morton
2001-11-30T06:09:45Z

mark_inode_dirty() is quite expensive for journalling filesystems,
and we're calling it a lot more than we need to.

--- linux-2.4.17-pre1/fs/inode.c Mon Nov 26 11:52:07 2001
+++ linux-akpm/fs/inode.c Thu Nov 29 21:53:02 2001
@@ -1187,6 +1187,8 @@ void __init inode_init(unsigned long mem

void update_atime (struct inode *inode)
{
+ if (inode->i_atime == CURRENT_TIME)
+ return;
if ( IS_NOATIME (inode) ) return;
if ( IS_NODIRATIME (inode) && S_ISDIR (inode->i_mode) ) return;
if ( IS_RDONLY (inode) ) return;

with this patch, the time to read a 10 meg file with 10 million
read()s falls from 38 seconds (ext3), 39 seconds (reiserfs) and
11.6 seconds (ext2) down to 10.5 seconds.

-