On Sun, Sep 23, 2012 at 08:56:32PM +0800, zwu.kernel@xxxxxxxxx wrote: > From: Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx> > > Fork and run one kernel kthread to calculate > that temperature based on some metrics kept > in custom frequency data structs, and store > the info in the hash table. No new kthreads, please. Use a per-superblock workqueue and a struct delayed_work to run periodic work on each superblock. That will also remove all the nasty, nasty !hot_track_temperature_update_kthread checks from the code, too. Also, I'd separate the work that the workqueue does from the patch that introduces the work queue. That way there is only one new thing to comment on in the patch. Further, I'd separate the aging code from the code that updates the temperature map into it's own patch as well.. Finally, you're going to need a shrinker to control the amount of memory that is used in tracking hot regions - if we are throwing inodes out of memory due to memory pressure, we most definitely are going to need to reduce the amount of memory the tracking code is using, even if it means losing useful information (i.e. the shrinker accelerates the aging process). Given the above, and the other comments earlier in the series, there's not a lot of point in me spending time commenting on ethe code in detail here as it will change significantly as a result of all the earlier comments.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
