On Tue, Sep 11, 2007 at 05:04:41PM -0700, Christoph Lameter wrote: > I would think that your approach would be slower since you always have to > populate 1 << N ptes when mmapping a file? Plus there is a lot of wastage I don't have to populate them, I could just map one at time. The only reason I want to populate every possible pte that could map that page (by checking vma ranges) is to _improve_ performance by decreasing the number of page faults of an order of magnitude. Then with the 62th bit after NX giving me a 64k tlb, I could decrease the frequency of the tlb misses too. > of memory because even a file with one character needs an order N page? So > there are less pages available for the same workload. This is a known issue. The same is true for ppc64 64k. If that really is an issue, that may need some generic solution with tail packing. > Then you are breaking mmap assumptions of applications becaused the order > N kernel will no longer be able to map 4k pages. You likely need a new > binary format that has pages correctly aligned. I know that we would need > one on IA64 if we go beyond the established page sizes. No you misunderstood the whole design. My patch will be 100% backwards compatible in all respects. If I could break backwards compatibility 70% of the complexity would go away... - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
