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authorSergey Fedorov <serge.fdrv@gmail.com>2016-07-15 20:58:50 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2016-09-13 19:08:43 +0200
commit74d356dd48b64eaa2a6104ac1493ca64cb31fa16 (patch)
treee04c2c06eae87993908e06048af9e078d533985b /cpu-exec.c
parent518615c6503ad78d3bb67ddf1cd848c4a41de02e (diff)
downloadqemu-arm-74d356dd48b64eaa2a6104ac1493ca64cb31fa16.tar.gz
tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump()
Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com> Signed-off-by: Sergey Fedorov <sergey.fedorov@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Message-Id: <20160715175852.30749-11-sergey.fedorov@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'cpu-exec.c')
-rw-r--r--cpu-exec.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/cpu-exec.c b/cpu-exec.c
index 7ca2b71a89..bd9fa5a538 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -282,7 +282,8 @@ static TranslationBlock *tb_find_physical(CPUState *cpu,
static TranslationBlock *tb_find_slow(CPUState *cpu,
target_ulong pc,
target_ulong cs_base,
- uint32_t flags)
+ uint32_t flags,
+ bool *have_tb_lock)
{
TranslationBlock *tb;
@@ -295,6 +296,7 @@ static TranslationBlock *tb_find_slow(CPUState *cpu,
*/
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.
@@ -305,7 +307,6 @@ static TranslationBlock *tb_find_slow(CPUState *cpu,
tb = tb_gen_code(cpu, pc, cs_base, flags, 0);
}
- tb_unlock();
mmap_unlock();
}
@@ -322,6 +323,7 @@ static inline TranslationBlock *tb_find_fast(CPUState *cpu,
TranslationBlock *tb;
target_ulong cs_base, pc;
uint32_t flags;
+ bool have_tb_lock = false;
/* we record a subset of the CPU state. It will
always be the same before a given translated block
@@ -330,7 +332,7 @@ static inline TranslationBlock *tb_find_fast(CPUState *cpu,
tb = atomic_rcu_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);
+ tb = tb_find_slow(cpu, pc, cs_base, flags, &have_tb_lock);
}
#ifndef CONFIG_USER_ONLY
/* We don't take care of direct jumps when address mapping changes in
@@ -343,13 +345,18 @@ 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();
+ if (!have_tb_lock) {
+ tb_lock();
+ have_tb_lock = true;
+ }
/* Check if translation buffer has been flushed */
if (cpu->tb_flushed) {
cpu->tb_flushed = false;
} else if (!tb->invalid) {
tb_add_jump(last_tb, tb_exit, tb);
}
+ }
+ if (have_tb_lock) {
tb_unlock();
}
return tb;