On 8/17/22 08:27, Ilya Leoshkevich wrote:
On Wed, 2022-08-17 at 08:15 -0500, Richard Henderson wrote:
On 8/17/22 06:08, Ilya Leoshkevich wrote:
@@ -2243,6 +2250,13 @@ void page_set_flags(target_ulong start,
target_ulong end, int flags)
(flags & PAGE_WRITE) &&
p->first_tb) {
tb_invalidate_phys_page(addr, 0);
+ } else {
+ TranslationBlock *tb;
+ int n;
+
+ PAGE_FOR_EACH_TB(p, tb, n) {
+ cpu_tb_jmp_cache_remove(tb);
+ }
}
Here you would use tb_jmp_cache_clear_page(), which should be moved
out of cputlb.c.
That was actually the first thing I tried.
Unfortunately tb_jmp_cache_clear_page() relies on
tb_jmp_cache_hash_func() returning the same top bits for addresses on
the same page. This is not the case for qemu-user: there this property
was traded for better hashing with quite impressive performance
improvements (6f1653180f570).
Oh my. Well, we could
(1) revert that patch because the premise is wrong,
(2) go with your per-tb clearing,
(3) clear the whole thing with cpu_tb_jmp_cache_clear
Ideally we'd have some benchmark numbers to inform the choice...
r~
