On 17-01-12 11:26:05, Dave Martin wrote: > General-purpose code in userspace is not expected to work correctly > if multiple threads are allowed to run concurrently with different > vector lengths in a single process. > > This patch adds an explicit flag PR_SVE_SET_VL_THREAD to request > this behaviour. Without the flag, vector length setting is > permitted only for a single-threaded process (which matches the > expected usage model of setting the vector length at process > startup). Hi Dave, PR_SVE_SET_VL_THREAD can be arch-independent, IMO, because prctl needs a scope. Looks some of them are system-wide, some of them are about threads within the same process (like, PR_MPX_ENABLE_MANAGEMENT). IOW, PR_SVE_SET_VL_THREAD can be general flag, to indicate the scope of each new ptrcl command is per-thread. I happen to see PR_SET_FP_MODE in man pages, which is about setting FP register modes in runtime. It is a little similar to setting VL in this patch. However the doc doesn't mention the effect or the scope of this command. -- Yao (齐尧) -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
