Messages in this thread | | | Subject | Re: [PATCH 2/6] change alloc function in pcpu_alloc_pages | From | Lee Schermerhorn <> | Date | Fri, 16 Apr 2010 15:13:09 -0400 |
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On Fri, 2010-04-16 at 11:07 -0500, Christoph Lameter wrote: > On Thu, 15 Apr 2010, Minchan Kim wrote: > > > I don't want to remove alloc_pages for UMA system. > > alloc_pages is the same as alloc_pages_any_node so why have it? > > > #define alloc_pages alloc_page_sexact_node > > > > What I want to remove is just alloc_pages_node. :) > > Why remove it? If you want to get rid of -1 handling then check all the > callsites and make sure that they are not using -1. > > Also could you define a constant for -1? -1 may have various meanings. One > is the local node and the other is any node.
NUMA_NO_NODE is #defined as (-1) and can be used for this purpose. '-1' has been replaced by this in many cases. It can be interpreted as "No node specified" == "any node is acceptable". But, it also has multiple meanings. E.g., in the hugetlb sysfs attribute and sysctl functions it indicates the global hstates [all nodes] vs a per node hstate. So, I suppose one could define a NUMA_ANY_NODE, to make the intention clear at the call site.
I believe that all usage of -1 to mean the local node has been removed, unless I missed one. Local allocation is now indicated by a mempolicy mode flag--MPOL_F_LOCAL. It's treated as a special case of MPOL_PREFERRED.
> The difference is if memory > policies are obeyed or not. Note that alloc_pages follows memory policies > whereas alloc_pages_node does not. > > Therefore > > alloc_pages() != alloc_pages_node( , -1) > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
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