On 08/17/2012 05:21 PM, Dan Magenheimer wrote: >> From: Seth Jennings [mailto:sjenning@xxxxxxxxxxxxxxxxxx] >> Subject: Re: [PATCH 0/4] promote zcache from staging >> >> On 08/09/2012 03:20 PM, Dan Magenheimer wrote >>> I also wonder if you have anything else unusual in your >>> test setup, such as a fast swap disk (mine is a partition >>> on the same rotating disk as source and target of the kernel build, >>> the default install for a RHEL6 system)? >> >> I'm using a normal SATA HDD with two partitions, one for >> swap and the other an ext3 filesystem with the kernel source. >> >>> Or have you disabled cleancache? >> >> Yes, I _did_ disable cleancache. I could see where having >> cleancache enabled could explain the difference in results. > > Sorry to beat a dead horse, but I meant to report this > earlier in the week and got tied up by other things. > > I finally got my test scaffold set up earlier this week > to try to reproduce my "bad" numbers with the RHEL6-ish > config file. > > I found that with "make -j28" and "make -j32" I experienced > __DATA CORRUPTION__. This was repeatable. I actually hit this for the first time a few hours ago when I was running performance for your rewrite. I didn't know what to make of it yet. The 24-thread kernel build failed when both frontswap and cleancache were enabled. > The type of error led me to believe that the problem was > due to concurrency of cleancache reclaim. I did not try > with cleancache disabled to prove/support this theory > but it is consistent with the fact that you (Seth) have not > seen a similar problem and has disabled cleancache. > > While this problem is most likely in my code and I am > suitably chagrined, it re-emphasizes the fact that > the current zcache in staging is 20-month old "demo" > code. The proposed new zcache codebase handles concurrency > much more effectively. I imagine this can be solved without rewriting the entire codebase. If your new code contains a fix for this, can we just pull it as a single patch? Seth -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>