Messages in this thread | | | Date | Fri, 30 Nov 2001 14:52:23 -0700 | From | Andreas Dilger <> | Subject | Re: [patch] smarter atime updates |
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On Nov 30, 2001 13:44 -0200, Marcelo Tosatti wrote: > Now are you sure this can't break anything ?
What fun would that be, if you couldn't follow in Linus' footsteps? People would get complacent if things didn't break now and again ;-).
Anyways, you never want to put a change that is not a specific bug fix in a -rc patch anyways. Save it for a -pre patch, where you expect at least some testing before it is released.
> On Thu, 29 Nov 2001, Andrew Morton wrote: > > 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.
Well, just doing a code check of the update_atime() and UPDATE_ATIME() users, and they are all in readlink(), follow_link(), open_namei(), and various fs _readdir() codes. None of them (AFAICS) depend on the mark_inode_dirty() as a side-effect. This means it should be safe.
Cheers, Andreas -- Andreas Dilger http://sourceforge.net/projects/ext2resize/ http://www-mddsp.enel.ucalgary.ca/People/adilger/
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