On Fri, 2015-08-07 at 09:14 -0700, Dan Williams wrote: > On Thu, Aug 6, 2015 at 10:43 AM, Ross Zwisler > <ross.zwis...@linux.intel.com> wrote: > > Prior to this change arch_has_wmb_pmem() was only called by > > arch_has_pmem_api(). Both arch_has_wmb_pmem() and arch_has_pmem_api() > > checked to make sure that CONFIG_ARCH_HAS_PMEM_API was enabled. > > > > Instead, remove one extra layer of indirection and the redundant > > CONFIG_ARCH_HAS_PMEM_API check, and just have arch_has_pmem_api() > > call __arch_has_wmb_pmem() directly. > > So I think this patch takes us further away from where we want to go > in the near term which is a finer grained pmem api. The class of > systems where (has_pmem_api() && !has_wmb_pmem()) is existing energy > backed nvdimm platforms. I'm assuming those platforms will want to > assert persistence guarantees in the absence of a pcommit-like > instruction, and that we want to stop gating arch_has_pmem_api() on > the presence of wmb_pmem() capability. In that case > arch_has_wmb_pmem() will be useful to have and that was the original > intent for including it, that intent did not seem to comprehended in > the changelog.
I think that we should only keep around functions that are actually used and useful. I agree that there could potentially be a use for a distinction like the one you are talking about when we try and properly support ADR systems and stop lumping them in with "non-PCOMMIT" systems like we are doing now. Right now, though, arch_has_wmb_pmem() is just redundant. If/when we add that new support in, we'll have to properly update this code anyway - let's not keep around unneeded code until then. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
