cputlb: Hoist timestamp outside of loops over tlbs

Do not call get_clock_realtime() in tlb_mmu_resize_locked,
but hoist outside of any loop over a set of tlbs.  This is
only two (indirect) callers, tlb_flush_by_mmuidx_async_work
and tlb_flush_page_locked, so not onerous.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

accel/tcg/cputlb.c

@@ -137,12 +137,12 @@ static void tlb_window_reset(CPUTLBDesc *desc, int64_t ns,
  * high), since otherwise we are likely to have a significant amount of
  * conflict misses.
  */
-static void tlb_mmu_resize_locked(CPUTLBDesc *desc, CPUTLBDescFast *fast)
+static void tlb_mmu_resize_locked(CPUTLBDesc *desc, CPUTLBDescFast *fast,
+                                  int64_t now)
 {
     size_t old_size = tlb_n_entries(fast);
     size_t rate;
     size_t new_size = old_size;
-    int64_t now = get_clock_realtime();
     int64_t window_len_ms = 100;
     int64_t window_len_ns = window_len_ms * 1000 * 1000;
     bool window_expired = now > desc->window_begin_ns + window_len_ns;
@@ -222,12 +222,13 @@ static void tlb_mmu_flush_locked(CPUTLBDesc *desc, CPUTLBDescFast *fast)
     memset(desc->vtable, -1, sizeof(desc->vtable));
 }
 
-static void tlb_flush_one_mmuidx_locked(CPUArchState *env, int mmu_idx)
+static void tlb_flush_one_mmuidx_locked(CPUArchState *env, int mmu_idx,
+                                        int64_t now)
 {
     CPUTLBDesc *desc = &env_tlb(env)->d[mmu_idx];
     CPUTLBDescFast *fast = &env_tlb(env)->f[mmu_idx];
 
-    tlb_mmu_resize_locked(desc, fast);
+    tlb_mmu_resize_locked(desc, fast, now);
     tlb_mmu_flush_locked(desc, fast);
 }
 
@@ -310,6 +311,7 @@ static void tlb_flush_by_mmuidx_async_work(CPUState *cpu, run_on_cpu_data data)
     CPUArchState *env = cpu->env_ptr;
     uint16_t asked = data.host_int;
     uint16_t all_dirty, work, to_clean;
+    int64_t now = get_clock_realtime();
 
     assert_cpu_is_self(cpu);
 
@@ -324,7 +326,7 @@ static void tlb_flush_by_mmuidx_async_work(CPUState *cpu, run_on_cpu_data data)
 
     for (work = to_clean; work != 0; work &= work - 1) {
         int mmu_idx = ctz32(work);
-        tlb_flush_one_mmuidx_locked(env, mmu_idx);
+        tlb_flush_one_mmuidx_locked(env, mmu_idx, now);
     }
 
     qemu_spin_unlock(&env_tlb(env)->c.lock);
@@ -446,7 +448,7 @@ static void tlb_flush_page_locked(CPUArchState *env, int midx,
         tlb_debug("forcing full flush midx %d ("
                   TARGET_FMT_lx "/" TARGET_FMT_lx ")\n",
                   midx, lp_addr, lp_mask);
-        tlb_flush_one_mmuidx_locked(env, midx);
+        tlb_flush_one_mmuidx_locked(env, midx, get_clock_realtime());
     } else {
         if (tlb_flush_entry_locked(tlb_entry(env, midx, page), page)) {
             tlb_n_used_entries_dec(env, midx);