On Fri, Jun 08, 2012 at 10:03:24AM +0300, Pekka Enberg wrote: > On Fri, Jun 8, 2012 at 9:58 AM, Anton Vorontsov > <anton.vorontsov@xxxxxxxxxx> wrote: > > If you're saying that we should set up a timer in the userland and > > constantly read /proc/vmstat, then we will cause CPU wake up > > every 100ms, which is not acceptable. Well, we can try to introduce > > deferrable timers for the userspace. But then it would still add > > a lot more overhead for our task, as this solution adds other two > > context switches to read and parse /proc/vmstat. I guess this is > > not a show-stopper though, so we can discuss this. > > > > Leonid, Pekka, what do you think about the idea? > > That's exactly the kind of half-assed ABI that lead to people > inventing out-of-tree lowmem notifiers in the first place. :-) Well, at least powersaving-wise, the solution w/ userland deferred timers would be much better then just looping over /proc/vmstat each 100ms, and it is comparable to vmevent. Not pretty, but still would work. > I'd be more interested to know what people think of Minchan's that > gets rid of vmstat sampling. I answered to Minchan's post. The thing is that Minchan's idea is not a substitution for vmevent. To me it seems like a shrinker w/ some pre-filter. Thanks, -- Anton Vorontsov Email: cbouatmailru@xxxxxxxxx -- 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>