On Mon, 21 Feb 2011, Andi Kleen wrote: > From: Andi Kleen <ak@xxxxxxxxxxxxxxx> > > Add a new __GFP_OTHER_NODE flag to tell the low level numa statistics > in zone_statistics() that an allocation is on behalf of another thread. > This way the local and remote counters can be still correct, even > when background daemons like khugepaged are changing memory > mappings. > > This only affects the accounting, but I think it's worth doing that > right to avoid confusing users. > This makes the accounting worse, NUMA_LOCAL is defined as "allocation from local node," meaning it's local to the allocating cpu, not local to the node being targeted. Further, preferred_zone has taken on a much more significant meaning other than just statistics: it impacts the behavior of memory compaction and how long congestion timeouts are, if a timeout is taken at all, depending on the I/O being done on behalf of the zone. A better way to address the issue is by making sure preferred_zone is actually correct by using the appropriate zonelist to be passed into the allocator in the first place. > I first tried to just pass down the right node, but this required > a lot of changes to pass down this parameter and at least one > addition of a 10th argument to a 9 argument function. Using > the flag is a lot less intrusive. > And adding a branch to every successful page allocation for statistics isn't intrusive? -- 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>