Messages in this thread | | | Date | Wed, 10 Feb 2010 20:36:34 +0900 | From | Tejun Heo <> | Subject | Re: [fuse-devel] [PATCH] FUSE/CUSE: implement direct mmap support |
| |
On 02/10/2010 08:22 PM, Tejun Heo wrote: > So, I don't think it's feasible to do the address matching from inside > the kernel without a lot of convolution.
To clarify a bit. The alignment is still a must. What's theoretically feasible with convolution is hiding the alignment from the userland server by adjusting virtual addresses of maps, but this will visibly break alignment as seen from the clients (e.g. client may not be able to unmap part of existing mmap and mmap SHMLBA aligned disjoint part there) even if we ignore the fact that implementation would be so invasive to the vm layer that it has no possibility of getting accepted.
SHMLBA is something that a user of shm should know anyway. I don't think it's too much to ask for from FUSE servers which would implement direct mmap and it's easy to detect and enforce too. The proposed libfuse patch abort()s if the condition is not met.
Thanks.
-- tejun
| |