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[Qemu-devel] [PATCH v3 11/11] tcg: Merge tb_find_slow() and tb_find_fast
From: |
Sergey Fedorov |
Subject: |
[Qemu-devel] [PATCH v3 11/11] tcg: Merge tb_find_slow() and tb_find_fast() |
Date: |
Tue, 12 Jul 2016 23:13:46 +0300 |
From: Sergey Fedorov <address@hidden>
These functions are not too big and can be merged together. This makes
locking scheme more clear and easier to follow.
Signed-off-by: Sergey Fedorov <address@hidden>
Signed-off-by: Sergey Fedorov <address@hidden>
---
cpu-exec.c | 72 ++++++++++++++++++++++++++------------------------------------
1 file changed, 30 insertions(+), 42 deletions(-)
diff --git a/cpu-exec.c b/cpu-exec.c
index 22c672fe03fd..6b01e8ceb0e8 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -278,45 +278,9 @@ static TranslationBlock *tb_find_physical(CPUState *cpu,
return qht_lookup(&tcg_ctx.tb_ctx.htable, tb_cmp, &desc, h);
}
-static TranslationBlock *tb_find_slow(CPUState *cpu,
- target_ulong pc,
- target_ulong cs_base,
- uint32_t flags,
- bool *have_tb_lock)
-{
- TranslationBlock *tb;
-
- tb = tb_find_physical(cpu, pc, cs_base, flags);
- if (!tb) {
-
- /* mmap_lock is needed by tb_gen_code, and mmap_lock must be
- * taken outside tb_lock. As system emulation is currently
- * single threaded the locks are NOPs.
- */
- mmap_lock();
- tb_lock();
- *have_tb_lock = true;
-
- /* There's a chance that our desired tb has been translated while
- * taking the locks so we check again inside the lock.
- */
- tb = tb_find_physical(cpu, pc, cs_base, flags);
- if (!tb) {
- /* if no translated code available, then translate it now */
- tb = tb_gen_code(cpu, pc, cs_base, flags, 0);
- }
-
- mmap_unlock();
- }
-
- /* We add the TB in the virtual pc hash table for the fast lookup */
- atomic_set(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)], tb);
- return tb;
-}
-
-static inline TranslationBlock *tb_find_fast(CPUState *cpu,
- TranslationBlock *last_tb,
- int tb_exit)
+static inline TranslationBlock *tb_find(CPUState *cpu,
+ TranslationBlock *last_tb,
+ int tb_exit)
{
CPUArchState *env = (CPUArchState *)cpu->env_ptr;
TranslationBlock *tb;
@@ -331,7 +295,31 @@ static inline TranslationBlock *tb_find_fast(CPUState *cpu,
tb = atomic_read(&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, &have_tb_lock);
+ tb = tb_find_physical(cpu, pc, cs_base, flags);
+ if (!tb) {
+
+ /* mmap_lock is needed by tb_gen_code, and mmap_lock must be
+ * taken outside tb_lock. As system emulation is currently
+ * single threaded the locks are NOPs.
+ */
+ mmap_lock();
+ tb_lock();
+ have_tb_lock = true;
+
+ /* There's a chance that our desired tb has been translated while
+ * taking the locks so we check again inside the lock.
+ */
+ tb = tb_find_physical(cpu, pc, cs_base, flags);
+ if (!tb) {
+ /* if no translated code available, then translate it now */
+ tb = tb_gen_code(cpu, pc, cs_base, flags, 0);
+ }
+
+ mmap_unlock();
+ }
+
+ /* We add the TB in the virtual pc hash table for the fast lookup */
+ atomic_set(&cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)], tb);
}
#ifndef CONFIG_USER_ONLY
/* We don't take care of direct jumps when address mapping changes in
@@ -436,7 +424,7 @@ static inline bool cpu_handle_exception(CPUState *cpu, int
*ret)
} 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, NULL, 0), true);
+ cpu_exec_nocache(cpu, 1, tb_find(cpu, NULL, 0), true);
*ret = -1;
return true;
#endif
@@ -620,7 +608,7 @@ int cpu_exec(CPUState *cpu)
atomic_mb_set(&cpu->tb_flushed, false); /* reset before first TB
lookup */
for(;;) {
cpu_handle_interrupt(cpu, &last_tb);
- tb = tb_find_fast(cpu, last_tb, tb_exit);
+ tb = tb_find(cpu, last_tb, tb_exit);
cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit, &sc);
/* Try to align the host and virtual clocks
if the guest is in advance */
--
1.9.1
[Qemu-devel] [PATCH v3 11/11] tcg: Merge tb_find_slow() and tb_find_fast(),
Sergey Fedorov <=
[Qemu-devel] [PATCH v3 10/11] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump(), Sergey Fedorov, 2016/07/12
Re: [Qemu-devel] [PATCH v3 00/11] Reduce lock contention on TCG hot-path, Paolo Bonzini, 2016/07/13
Re: [Qemu-devel] [PATCH v3 00/11] Reduce lock contention on TCG hot-path, Sergey Fedorov, 2016/07/13
Re: [Qemu-devel] [PATCH v3 00/11] Reduce lock contention on TCG hot-path, Alex Bennée, 2016/07/14