On Fri, Dec 12, 2014 at 09:42:15AM +0900, Akira Hayakawa wrote: > The SSD-caching should be log-structured. No argument there, and this is why I've supported you with dm-writeboost over the last couple of years. However, after looking at the current code, and using it I think it's a long, long way from being ready for production. As we've already discussed there are some very naive design decisions in there, such as copying every bio payload to another memory buffer, splitting all io down to 4k. Think about the cpu overhead and memory consumption! Think about how it will perform when memory is constrained and it can't allocate many of those rambufs! I'm sure more issues will be found if I read further. I'm sorry to have disappointed you so, but if I let this go upstream it would mean a massive amount of support work for me, not to mention a damaged reputation for dm. Mike raised the question of why you want this in the kernel so much? You'd find none of the distros would support it; so it doesn't widen your audience much. It's far better for you to maintain it outside of the kernel at this point. Any users will be bold, adventurous people, who will be quite capable of building a kernel module. - Joe -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
