On 05.03.2015 [17:08:04 -0500], Tejun Heo wrote: > Hello, > > On Thu, Mar 05, 2015 at 01:58:27PM -0800, David Rientjes wrote: > > I'm not sure why this is being proposed as a powerpc patch and now a patch > > for mem_cgroup_css_alloc(). In other words, why do we have to allocate > > for all possible nodes? We should only be allocating for online nodes in > > N_MEMORY with mem hotplug disabled initially and then have a mem hotplug > > callback implemented to alloc_mem_cgroup_per_zone_info() for nodes that > > transition from memoryless -> memory. The extra bonus is that > > alloc_mem_cgroup_per_zone_info() need never allocate remote memory and the > > TODO in that function can be removed. > > For cpus, the general direction is allocating for all possible cpus. > For iterations, we alternate between using all possibles and onlines > depending on the use case; however, the general idea is that the > possibles and onlines aren't gonna be very different. NR_CPUS and > MAX_NUMNODES gotta accomodate the worst possible case the kernel may > run on but the possible masks should be set to the actually possible > subset during boot so that the kernel don't end up allocating for and > iterating over things which can't ever exist.
Makes sense to me. > It can be argued that we should always stick to the online masks for > allocation and iteration; however, that usually requires more > complexity and the only cases where this mattered have been when the > boot code got it wrong and failed to set the possible masks correctly, > which also seems to be the case here. I don't see any reason to > deviate here. So, do you agree with the general direction of my change? :) Thanks, Nish _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
