On Mon, Nov 30, 2009 at 03:28:40PM -0500, Lee Schermerhorn wrote: > linux/topology.h now depends on */percpu.h to implement numa_node_id() > and numa_mem_id(). Not so much an issue for x86 because its > asm/topology.h already depended on its asm/percpu.h. But ia64, for > instance--maybe any arch that doesn't already implement numa_node_id() > as a percpu variable--didn't define this_cpu_read() for > linux/topology.h. > > So, I included <linux/percpu.h>. > > linux/percpu.h, for reasons of its own, includes linux/swap.h which typo there ... slab.h, not swap.h. I thought we might be able to break the cycle here, but slab.h is more reasonable than swap.h. We could move __alloc_percpu out of line ... it's only inline for the !SMP case. > includes linux/gfp.h which includes linux/topology.h for the definition > of numa_node_id(). topology.h hasn't gotten around to defining > numa_node_id() yet--it's still including percpu.h. ... > > Looking at other asm/foo.h and asm-generic/foo.h relationships, I see > that some define the generic version of the api in the asm-generic > header if the arch asm header hasn't already defined it. asm/topology.h > is an instance of this. It includes asm-generic/topology.h after > defining arch specific versions of some of the api. > > Following this model, I moved the generic definitions of the percpu api > back to the asm-generic version where it would be available without the > inclusion of swap.h, et al. > > I tried including <asm/percpu.h> in linux/topology.h but the was advised > to use the generic header. So I followed the model of the x86 > asm/topology.h and included asm/percpu.h in the ia64 asm/topology.h, > making the definitions visible to linux/topology.h. > > This reminds me that I should add to the patch description a 3rd item > required for an arch to use the generic percpu numa_node_id() > implementation: make the percpu variable access interface visible via > asm/topology.h. > > Does that sound reasonable? > > Lee > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-arch" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
