Messages in this thread | | | From | Nick Piggin <> | Subject | Re: [Approach #2] [RFC][PATCH] Remove cgroup member from struct page | Date | Thu, 11 Sep 2008 07:02:44 +1000 |
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On Wednesday 10 September 2008 21:03, KAMEZAWA Hiroyuki wrote: > On Thu, 11 Sep 2008 06:44:37 +1000 > > Nick Piggin <nickpiggin@yahoo.com.au> wrote: > > On Wednesday 10 September 2008 11:49, KAMEZAWA Hiroyuki wrote: > > > On Tue, 9 Sep 2008 18:20:48 -0700 > > > > > > Balbir Singh <balbir@linux.vnet.ibm.com> wrote: > > > > * KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> [2008-09-09 > > > > 21:30:12]: OK, here is approach #2, it works for me and gives me > > > > really good performance (surpassing even the current memory > > > > controller). I am seeing almost a 7% increase > > > > > > This number is from pre-allcation, maybe. > > > We really do alloc-at-boot all page_cgroup ? This seems a big change. > > > > It seems really nice to me -- we get the best of both worlds, less > > overhead for those who don't enable the memory controller, and even > > better performance for those who do. > > No trobles for me for allocating-all-at-boot policy. > My small concern is > - wasting page_cgroup for hugepage area. > - memory hotplug
In those cases you still waste the struct page area too. I realise that isn't a good way to justify even more wastage. But I guess it is relatively low. At least, I would think the users would be more happy to get a 7% performance increase for small pages! :)
> > Are you expecting many users to want to turn this on and off at runtime? > > I wouldn't expect so, but I don't know enough about them. > > There is no runtime switch. only at boot.
Fine
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