On Thu, Sep 27, 2012 at 12:03 PM, Dave Chinner <david@xxxxxxxxxxxxx> wrote: > 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. If no new kthread is created, which kthread will work on these delayed_work tasks? > > 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). Great, I agree with you. > > 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.... OK, i will complete the code change based on all your earlier comments ASAP. > > Cheers, > > Dave. > -- > Dave Chinner > david@xxxxxxxxxxxxx > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Regards, Zhi Yong Wu -- 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
