diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2023-03-03 14:37:51 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2023-06-06 09:42:14 +0200 |
| commit | 06831001ac8949b0801e0d20c347d97339769a20 (patch) | |
| tree | 01c418078a78ff8049bf5eb7bc36cf3e3bddcb14 /accel | |
| parent | 09a49afeae2542993d4cdc5d7af22abdfce7a3ba (diff) | |
atomics: eliminate mb_read/mb_set
qatomic_mb_read and qatomic_mb_set were the very first atomic primitives
introduced for QEMU; their semantics are unclear and they provide a false
sense of safety.
The last use of qatomic_mb_read() has been removed, so delete it.
qatomic_mb_set() instead can survive as an optimized
qatomic_set()+smp_mb(), similar to Linux's smp_store_mb(), but
rename it to qatomic_set_mb() to match the order of the two
operations.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'accel')
| -rw-r--r-- | accel/tcg/cpu-exec.c | 2 | ||||
| -rw-r--r-- | accel/tcg/tcg-accel-ops-mttcg.c | 2 | ||||
| -rw-r--r-- | accel/tcg/tcg-accel-ops-rr.c | 4 |
3 files changed, 4 insertions, 4 deletions
diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c index 1cf4f1fa22..42086525d7 100644 --- a/accel/tcg/cpu-exec.c +++ b/accel/tcg/cpu-exec.c @@ -774,7 +774,7 @@ static inline bool cpu_handle_interrupt(CPUState *cpu, * Ensure zeroing happens before reading cpu->exit_request or * cpu->interrupt_request (see also smp_wmb in cpu_exit()) */ - qatomic_mb_set(&cpu_neg(cpu)->icount_decr.u16.high, 0); + qatomic_set_mb(&cpu_neg(cpu)->icount_decr.u16.high, 0); if (unlikely(qatomic_read(&cpu->interrupt_request))) { int interrupt_request; diff --git a/accel/tcg/tcg-accel-ops-mttcg.c b/accel/tcg/tcg-accel-ops-mttcg.c index 5d72c9b1bd..b320ff0037 100644 --- a/accel/tcg/tcg-accel-ops-mttcg.c +++ b/accel/tcg/tcg-accel-ops-mttcg.c @@ -119,7 +119,7 @@ static void *mttcg_cpu_thread_fn(void *arg) } } - qatomic_mb_set(&cpu->exit_request, 0); + qatomic_set_mb(&cpu->exit_request, 0); qemu_wait_io_event(cpu); } while (!cpu->unplug || cpu_can_run(cpu)); diff --git a/accel/tcg/tcg-accel-ops-rr.c b/accel/tcg/tcg-accel-ops-rr.c index 70b9b89073..23e4d0f452 100644 --- a/accel/tcg/tcg-accel-ops-rr.c +++ b/accel/tcg/tcg-accel-ops-rr.c @@ -244,7 +244,7 @@ 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); + qatomic_set_mb(&rr_current_cpu, cpu); current_cpu = cpu; @@ -287,7 +287,7 @@ static void *rr_cpu_thread_fn(void *arg) qatomic_set(&rr_current_cpu, NULL); if (cpu && cpu->exit_request) { - qatomic_mb_set(&cpu->exit_request, 0); + qatomic_set_mb(&cpu->exit_request, 0); } if (icount_enabled() && all_cpu_threads_idle()) { |