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[Qemu-devel] [PATCH 2/8] cpu-exec: remove tb_lock from hot path
From: |
Emilio G. Cota |
Subject: |
[Qemu-devel] [PATCH 2/8] cpu-exec: remove tb_lock from hot path |
Date: |
Wed, 24 Aug 2016 18:17:57 -0400 |
Signed-off-by: Emilio G. Cota <address@hidden>
---
cpu-exec.c | 38 +++++++++++---------------------------
1 file changed, 11 insertions(+), 27 deletions(-)
diff --git a/cpu-exec.c b/cpu-exec.c
index 041f8b7..63d739a 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -309,34 +309,18 @@ static TranslationBlock *tb_find_slow(CPUState *cpu,
TranslationBlock *tb;
tb = tb_find_physical(cpu, pc, cs_base, flags);
- if (tb) {
- goto found;
- }
-
-#ifdef CONFIG_USER_ONLY
- /* mmap_lock is needed by tb_gen_code, and mmap_lock must be
- * taken outside tb_lock. Since we're momentarily dropping
- * tb_lock, there's a chance that our desired tb has been
- * translated.
- */
- tb_unlock();
- mmap_lock();
- tb_lock();
- tb = tb_find_physical(cpu, pc, cs_base, flags);
- if (tb) {
+ if (!tb) {
+ mmap_lock();
+ tb_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);
+ }
+ tb_unlock();
mmap_unlock();
- goto found;
}
-#endif
-
- /* if no translated code available, then translate it now */
- tb = tb_gen_code(cpu, pc, cs_base, flags, 0);
-
-#ifdef CONFIG_USER_ONLY
- mmap_unlock();
-#endif
-found:
/* we add the TB in the virtual pc hash table */
cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)] = tb;
return tb;
@@ -355,7 +339,6 @@ 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)) {
@@ -379,9 +362,10 @@ static inline TranslationBlock *tb_find_fast(CPUState *cpu,
#endif
/* See if we can patch the calling TB. */
if (*last_tb && !qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) {
+ tb_lock();
tb_add_jump(*last_tb, tb_exit, tb);
+ tb_unlock();
}
- tb_unlock();
return tb;
}
--
2.5.0
- Re: [Qemu-devel] [PATCH] aarch64: use TSX for ldrex/strex, (continued)
- Re: [Qemu-devel] [PATCH] aarch64: use TSX for ldrex/strex, Emilio G. Cota, 2016/08/17
- Re: [Qemu-devel] [PATCH] aarch64: use TSX for ldrex/strex, Emilio G. Cota, 2016/08/17
- Re: [Qemu-devel] [PATCH] aarch64: use TSX for ldrex/strex, Richard Henderson, 2016/08/17
- Re: [Qemu-devel] [PATCH] aarch64: use TSX for ldrex/strex, Richard Henderson, 2016/08/18
- Re: [Qemu-devel] [PATCH] aarch64: use TSX for ldrex/strex, Emilio G. Cota, 2016/08/24
- [Qemu-devel] [PATCH 1/8] cpu list: convert to RCU QLIST, Emilio G. Cota, 2016/08/24
- [Qemu-devel] [PATCH 3/8] rcu: add rcu_read_lock_held(), Emilio G. Cota, 2016/08/24
- [Qemu-devel] [PATCH 7/8] htm: add powerpc64 intrinsics, Emilio G. Cota, 2016/08/24
- [Qemu-devel] [PATCH 6/8] htm: add header to abstract Hardware Transactional Memory intrinsics, Emilio G. Cota, 2016/08/24
- [Qemu-devel] [PATCH 8/8] target-arm/a64: use HTM with stop-the-world fall-back path, Emilio G. Cota, 2016/08/24
- [Qemu-devel] [PATCH 2/8] cpu-exec: remove tb_lock from hot path,
Emilio G. Cota <=
- [Qemu-devel] [PATCH 4/8] target-arm: helper fixup for paired atomics, Emilio G. Cota, 2016/08/24
- [Qemu-devel] [PATCH 5/8] linux-user: add stop-the-world to be called from CPU loop, Emilio G. Cota, 2016/08/24
Re: [Qemu-devel] MTTCG status updates, benchmark results and KVM forum plans, Alex Bennée, 2016/08/16