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charset="utf-8" Note that qatomic_mb_set can remain, similar to how Linux has smp_store_mb (an optimized version of following a store with a full memory barrier). Signed-off-by: Paolo Bonzini Reviewed-by: Richard Henderson --- accel/tcg/tcg-accel-ops-rr.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/accel/tcg/tcg-accel-ops-rr.c b/accel/tcg/tcg-accel-ops-rr.c index 290833a37fb2..055f6ae29553 100644 --- a/accel/tcg/tcg-accel-ops-rr.c +++ b/accel/tcg/tcg-accel-ops-rr.c @@ -71,11 +71,13 @@ static void rr_kick_next_cpu(void) { CPUState *cpu; do { - cpu =3D qatomic_mb_read(&rr_current_cpu); + cpu =3D qatomic_read(&rr_current_cpu); if (cpu) { cpu_exit(cpu); } - } while (cpu !=3D qatomic_mb_read(&rr_current_cpu)); + /* Finish kicking this cpu before reading again. */ + smp_mb(); + } while (cpu !=3D qatomic_read(&rr_current_cpu)); } =20 static void rr_kick_thread(void *opaque) @@ -206,8 +208,9 @@ static void *rr_cpu_thread_fn(void *arg) } =20 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 =3D cpu; =20 qemu_clock_enable(QEMU_CLOCK_VIRTUAL, @@ -245,7 +248,7 @@ static void *rr_cpu_thread_fn(void *arg) cpu =3D CPU_NEXT(cpu); } /* while (cpu && !cpu->exit_request).. */ =20 - /* Does not need qatomic_mb_set because a spurious wakeup is okay.= */ + /* Does not need a memory barrier because a spurious wakeup is oka= y. */ qatomic_set(&rr_current_cpu, NULL); =20 if (cpu && cpu->exit_request) { --=20 2.40.1