diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2023-03-03 13:18:23 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2023-05-18 08:53:51 +0200 |
| commit | 2e73952926381b7ff8224bbf80ff7b035053595f (patch) | |
| tree | 564abff974e896cb318e17f745c6691384e17033 /accel | |
| parent | 856e23a0fb92b0949eace7f43a521e0214246735 (diff) | |
tcg: round-robin: do not use mb_read for rr_current_cpu
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'accel')
| -rw-r--r-- | accel/tcg/tcg-accel-ops-rr.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/accel/tcg/tcg-accel-ops-rr.c b/accel/tcg/tcg-accel-ops-rr.c index 5788efa5ff..b6d10fa9a2 100644 --- a/accel/tcg/tcg-accel-ops-rr.c +++ b/accel/tcg/tcg-accel-ops-rr.c @@ -72,11 +72,13 @@ static void rr_kick_next_cpu(void) { CPUState *cpu; do { - cpu = qatomic_mb_read(&rr_current_cpu); + cpu = qatomic_read(&rr_current_cpu); if (cpu) { cpu_exit(cpu); } - } while (cpu != qatomic_mb_read(&rr_current_cpu)); + /* Finish kicking this cpu before reading again. */ + smp_mb(); + } while (cpu != qatomic_read(&rr_current_cpu)); } static void rr_kick_thread(void *opaque) @@ -241,8 +243,9 @@ static void *rr_cpu_thread_fn(void *arg) } while (cpu && cpu_work_list_empty(cpu) && !cpu->exit_request) { - + /* Store rr_current_cpu before evaluating cpu_can_run(). */ qatomic_mb_set(&rr_current_cpu, cpu); + current_cpu = cpu; qemu_clock_enable(QEMU_CLOCK_VIRTUAL, @@ -280,7 +283,7 @@ static void *rr_cpu_thread_fn(void *arg) cpu = CPU_NEXT(cpu); } /* while (cpu && !cpu->exit_request).. */ - /* Does not need qatomic_mb_set because a spurious wakeup is okay. */ + /* Does not need a memory barrier because a spurious wakeup is okay. */ qatomic_set(&rr_current_cpu, NULL); if (cpu && cpu->exit_request) { |