Hi, On Thu, 2011-04-28 at 18:09 +0800, Tejun Heo wrote: > On Thu, Apr 28, 2011 at 11:28:04AM +0800, Shaohua Li wrote: > > > Okay, this communication failure isn't my fault. Please re-read what > > > I wrote before, my concern wasn't primarily about pathological worst > > > case - if that many concurrent updates are happening && the counter > > > needs to be accurate, it can't even use atomic counter. It should be > > > doing full exclusion around the counter and the associated operation > > > _together_. > > > > > > I'm worried about sporadic erratic behavior happening regardless of > > > update frequency and preemption would contribute but isn't necessary > > > for that to happen. > > > > Ok, I misunderstood the mail you sent to Christoph, sorry. So you have > > no problem about the atomic convert. I'll update the patch against base > > tree, given the preemptless patch has problem. > > Hmm... we're now more lost than ever. :-( Can you please re-read my > message two replies ago? The one where I talked about sporadic > erratic behaviors in length and why I was worried about it. > > In your last reply, you talked about preemption and that you didn't > have problems with disabling preemption, which, unfortunately, doesn't > have much to do with my concern with the sporadic erratic behaviors > and that's what I pointed out in my previous reply. So, it doesn't > feel like anything is resolved. ok, I got your point. I'd agree there is sporadic erratic behaviors, but I expect there is no problem here. We all agree the worst case is the same before/after the change. Any program should be able to handle the worst case, otherwise the program itself is buggy. Discussing a buggy program is meaningless. After the change, something behavior is changed, but the worst case isn't. So I don't think this is a big problem. Thanks, Shaohua -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>