Dave Airlie <airlied@xxxxxxxxxx> writes:I agree that wbinvd() seems to be faster on large arrays on the processors I've tested. But isn't there a severe latency problem with that instruction, that makes people really want to avoid it in all possible cases?
+#define CPA_FLUSHTLB 1
+#define CPA_ARRAY 2
I don't think CPA_ARRAY should be a separate case. Rather single
page flushing should be an array with only a single entry. pageattr
is already very complex, no need to make add more special cases.
+
+ /*
+ * Only flush present addresses:
+ */
+ if (pte && (pte_val(*pte) & _PAGE_PRESENT))
+ clflush_cache_range((void *) *addr, PAGE_SIZE);
Also it is doubtful clflush really makes sense on a large array. Just
doing wbinvd might be faster then. Or perhaps better supporting Self-Snoop
should be revisited, that would at least eliminate it on most Intel CPUs.
-Andi