On Fri, Apr 29, 2016 at 11:09:23AM -0700, Dave Hansen wrote: > Once we *HAVE* XSAVES support, it also opens up the possibilities for > doing things like dynamic XSAVE buffer allocation. For instance, let > threads that are not _using_ AVX-512 not waste the 2k of space for it.
If we can somehow modify exec* system call to scan the executable binary (in user space) and pass along a bitmask containing xfeatures used in the binary, and XSAVES is enabled in the kernel, we can easily save a lot of memory. The kernel only needs to allocate space for tasks that actually use xstates; most of them do not.
