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[Qemu-devel] [PATCH v5 6/6] cpu-exec: Move TB chaining into tb_find_fast
From: |
Sergey Fedorov |
Subject: |
[Qemu-devel] [PATCH v5 6/6] cpu-exec: Move TB chaining into tb_find_fast() |
Date: |
Tue, 26 Apr 2016 13:41:19 +0300 |
From: Sergey Fedorov <address@hidden>
Move tb_add_jump() call and surrounding code from cpu_exec() into
tb_find_fast(). That simplifies cpu_exec() a little by hiding the direct
chaining optimization details into tb_find_fast(). It also allows to
move tb_lock()/tb_unlock() pair into tb_find_fast(), putting it closer
to tb_find_slow() which also manipulates the lock.
Suggested-by: Alex Bennée <address@hidden>
Signed-off-by: Sergey Fedorov <address@hidden>
Signed-off-by: Sergey Fedorov <address@hidden>
---
cpu-exec.c | 41 ++++++++++++++++++++++-------------------
1 file changed, 22 insertions(+), 19 deletions(-)
diff --git a/cpu-exec.c b/cpu-exec.c
index 8ba899b47a23..44dae04ae819 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -320,7 +320,9 @@ found:
return tb;
}
-static inline TranslationBlock *tb_find_fast(CPUState *cpu)
+static inline TranslationBlock *tb_find_fast(CPUState *cpu,
+ TranslationBlock **last_tb,
+ int tb_exit)
{
CPUArchState *env = (CPUArchState *)cpu->env_ptr;
TranslationBlock *tb;
@@ -331,11 +333,27 @@ static inline TranslationBlock *tb_find_fast(CPUState
*cpu)
always be the same before a given translated block
is executed. */
cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
+ tb_lock();
tb = cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)];
if (unlikely(!tb || tb->pc != pc || tb->cs_base != cs_base ||
tb->flags != flags)) {
tb = tb_find_slow(cpu, pc, cs_base, flags);
}
+ if (cpu->tb_flushed) {
+ /* Ensure that no TB jump will be modified as the
+ * translation buffer has been flushed.
+ */
+ *last_tb = NULL;
+ cpu->tb_flushed = false;
+ }
+ /* see if we can patch the calling TB. When the TB
+ spans two pages, we cannot safely do a direct
+ jump. */
+ if (*last_tb && tb->page_addr[1] == -1 &&
+ !qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) {
+ tb_add_jump(*last_tb, tb_exit, tb);
+ }
+ tb_unlock();
return tb;
}
@@ -441,7 +459,8 @@ int cpu_exec(CPUState *cpu)
} else if (replay_has_exception()
&& cpu->icount_decr.u16.low + cpu->icount_extra == 0) {
/* try to cause an exception pending in the log */
- cpu_exec_nocache(cpu, 1, tb_find_fast(cpu), true);
+ last_tb = NULL; /* Avoid chaining TBs */
+ cpu_exec_nocache(cpu, 1, tb_find_fast(cpu, &last_tb, 0), true);
ret = -1;
break;
#endif
@@ -511,23 +530,7 @@ int cpu_exec(CPUState *cpu)
cpu->exception_index = EXCP_INTERRUPT;
cpu_loop_exit(cpu);
}
- tb_lock();
- tb = tb_find_fast(cpu);
- if (cpu->tb_flushed) {
- /* Ensure that no TB jump will be modified as the
- * translation buffer has been flushed.
- */
- last_tb = NULL;
- cpu->tb_flushed = false;
- }
- /* see if we can patch the calling TB. When the TB
- spans two pages, we cannot safely do a direct
- jump. */
- if (last_tb && tb->page_addr[1] == -1
- && !qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) {
- tb_add_jump(last_tb, tb_exit, tb);
- }
- tb_unlock();
+ tb = tb_find_fast(cpu, &last_tb, tb_exit);
if (likely(!cpu->exit_request)) {
uintptr_t ret;
trace_exec_tb(tb, tb->pc);
--
2.8.1
- [Qemu-devel] [PATCH v5 0/6] tcg: Misc clean-up patches, Sergey Fedorov, 2016/04/26
- [Qemu-devel] [PATCH v5 2/6] tcg: reorganize tb_find_physical loop, Sergey Fedorov, 2016/04/26
- [Qemu-devel] [PATCH v5 1/6] tcg: code_bitmap is not used by user-mode emulation, Sergey Fedorov, 2016/04/26
- [Qemu-devel] [PATCH v5 3/6] cpu-exec: elide more icount code if CONFIG_USER_ONLY, Sergey Fedorov, 2016/04/26
- [Qemu-devel] [PATCH v5 4/6] tcg: Clean up from 'next_tb', Sergey Fedorov, 2016/04/26
- [Qemu-devel] [PATCH v5 5/6] tcg: Rework tb_invalidated_flag, Sergey Fedorov, 2016/04/26
- [Qemu-devel] [PATCH v5 6/6] cpu-exec: Move TB chaining into tb_find_fast(),
Sergey Fedorov <=