On Fri, 25 Apr 2008, Andi Kleen wrote: > > Not sure how the fixmap is better. It's pretty much equivalent, isn't it? > Perhaps a little cheaper, but the code shouldn't be performance critical. I have no really strong opinions. However, we do have a *lot* of lock prefixes in the kernel, and fixmaps are a lot cheaper than vmap(). It may not be performance-critical, but for me the "locks" section for the kernel is 0x8060 bytes long, which would seem to say that this is called four thousand times for each suspend and resume. With each invocation being thousands of instructions and a cross-CPU IPI for the tlb flush, that kind of stuff adds up. We're likely talking real fractions of a second, rather than milliseconds. But no, I didn't time it or really think very deeply about it. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
