On Wed, 2007-08-15 at 13:36 -0700, Christoph Lameter wrote: > On Wed, 15 Aug 2007, Lee Schermerhorn wrote: > > > > So its always true for node 0. The "bit" is set. > > > > The issue is with the N_*_MEMORY masks. They don't get initialized > > properly because node_set_state() is a no-op if !NUMA. So, where we > > look for intersections with or where we AND with the N_*_MEMORY masks we > > get the empty set. > > That is intentional. Memory is always present if you are on !NUMA. You can > simply use a default nodemask where only node 0 is set. That is what the > fallback provides. Maybe it does not provide the right thing for cpusets? > > > > We are trying to get cpusets to work with !NUMA? > > > > Well, yes. In Serge's case, he's trying to use cpusets with !NUMA. > > He'll have to comment on the reasons for that. Looking at all of the > > #ifdefs and init/Kconfig, CPUSET does not depend on NUMA--only SMP and > > CONTAINERS [altho' methinks CPUSET should select CONTAINERS rather than > > depend on it...]. So, you can use cpusets to partition of cpus in > > non-NUMA configs. > > Looks like we need to fix cpuset nodemasks for the !NUMA case then? > It cannot expect to find valid nodemasks if !NUMA.
Well, OK. But Paul really hates #ifdefs in kernel/cpusets.c. He's asked me to remove them before, so I avoided them here. Cpusets really should use only nodes with memory--i.e., the N_HIGH_MEMORY state. > > > In the more general case, tho', I'm looking at all uses of the > > node_online_map and for_each_online_node, for instances where they > > should be replaced with one of the *_MEMORY masks. IMO, generic code > > that is compiled independent of any CONFIG option, like NUMA, should > > just work, independent of the config. Currently, as Serge has shown, > > AFAIK this works except for cpusets. So far. I'm replacing other usage of node_online_map with the N_HIGH_MEMORY mask, as we discussed. I should have that patch ready to post tomorrow. > > > this is not the case. So, I think we should fix the *_MEMORY maps to be > > correctly populated in both the NUMA and !NUMA cases. A couple of > > options: > > There is no point in having a variable if you know the results because of > !NUMA. That is the way nodemask.h has always operated. But, the mask--the N_HIGH_MEMORY array element, that is--is there for both NUMA and !NUMA [== N_NORMAL_MEMORY for !CONFIG_HIGHMEM]. We just don't initialize it for the !NUMA case, currently. > > > Thoughts? > > Lets get either rid of the definitions for the nodemasks in the !NUMA > case or fix their contents to have the right constant value expected in > cpusets. That's what the patch I posted today [option 2] does--statically initializes the N_*_MEMORY and N_CPU masks to indicate that node 0 exists. Serge and Dhaval have tested it on their platform and it solves the cpuset mount problem. Lee - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/