On Thu, 21 Apr 2011 00:09:13 -0700 Ying Han <yinghan@xxxxxxxxxx> wrote: > On Wed, Apr 20, 2011 at 8:43 PM, KAMEZAWA Hiroyuki < > kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: > > > Ying, please take this just a hint, you don't need to implement this as is. > > > > Thank you for the patch. > > > > == > > Now, memcg-kswapd is created per a cgroup. Considering there are users > > who creates hundreds on cgroup on a system, it consumes too much > > resources, memory, cputime. > > > > This patch creates a thread pool for memcg-kswapd. All memcg which > > needs background recalim are linked to a list and memcg-kswapd > > picks up a memcg from the list and run reclaim. This reclaimes > > SWAP_CLUSTER_MAX of pages and putback the memcg to the lail of > > list. memcg-kswapd will visit memcgs in round-robin manner and > > reduce usages. > > > > This patch does > > > > - adds memcg-kswapd thread pool, the number of threads is now > > sqrt(num_of_cpus) + 1. > > - use unified kswapd_waitq for all memcgs. > > > > So I looked through the patch, it implements an alternative threading model > using thread-pool. Also it includes some changes on calculating how much > pages to reclaim per memcg. Other than that, all the existing implementation > of per-memcg-kswapd seems not being impacted. > > I tried to apply the patch but get some conflicts on vmscan.c/ I will try > some manual work tomorrow. Meantime, after applying the patch, I will try to > test it w/ the same test suite i used on original patch. AFAIK, the only > difference of the two threading model is the amount of resources we consume > on the kswapd kernel thread, which shouldn't have run-time performance > differences. > I hope so. To be honest, I don't like one-thread-per-one-job model because it's wastes resouce and cache foot print and what we can do is just hoping schedulre schedules tasks well. I like one-thread-per-mulutiple job and switching in finer grain with knowledge of memory cgroup. Thanks, -Kame -- 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>