On Mon, Apr 11, 2011 at 02:36:53PM -0400, Christoph Hellwig wrote: > How do you produce so many atime-dirty inodes? With relatime we > should have cut down on the requirement for those a lot. Copy a bunch of files, then md5sum them. The copy modifies c/mtime, the md5sum modifies atime, sees mtime is younger than atime, updates atime and dirties the inode. i.e.: $ touch foo $ stat foo File: `foo' Size: 0 Blocks: 0 IO Block: 4096 regular empty file Device: fe02h/65026d Inode: 150756489 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 1000/ dave) Gid: ( 1000/ dave) Access: 2011-04-12 07:08:24.668542636 +1000 Modify: 2011-04-12 07:08:24.668542636 +1000 Change: 2011-04-12 07:08:24.668542636 +1000 $ cp README foo cp: overwrite `foo'? y $ stat foo File: `foo' Size: 17525 Blocks: 40 IO Block: 4096 regular file Device: fe02h/65026d Inode: 150756489 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 1000/ dave) Gid: ( 1000/ dave) Access: 2011-04-12 07:08:24.668542636 +1000 Modify: 2011-04-12 07:08:44.676108103 +1000 Change: 2011-04-12 07:08:44.676108103 +1000 $ md5sum foo 9eb709847626f3663ea66121f10a27d7 foo $ stat foo File: `foo' Size: 17525 Blocks: 40 IO Block: 4096 regular file Device: fe02h/65026d Inode: 150756489 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 1000/ dave) Gid: ( 1000/ dave) Access: 2011-04-12 07:09:00.223770431 +1000 Modify: 2011-04-12 07:08:44.676108103 +1000 Change: 2011-04-12 07:08:44.676108103 +1000 $ > Do you have traces that show if we're kicking off additional data > writeback this way too, or just pushing timestamp updates into > the AIL? For the test workload, it just pushes timestamp updates into the AIL as that is the only thing that is dirtying the inodes when the OOM occurs. In other situations, I have no evidence either way, but I have not noticed any performance changes from a high level. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
