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[PATCH v10 71/73] cpus-common: release BQL earlier in run_on_cpu
From: |
Robert Foley |
Subject: |
[PATCH v10 71/73] cpus-common: release BQL earlier in run_on_cpu |
Date: |
Wed, 17 Jun 2020 17:02:29 -0400 |
From: "Emilio G. Cota" <cota@braap.org>
After completing the conversion to per-CPU locks, there is no need
to release the BQL after having called cpu_kick.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Robert Foley <robert.foley@linaro.org>
---
cpus-common.c | 20 +++++---------------
1 file changed, 5 insertions(+), 15 deletions(-)
diff --git a/cpus-common.c b/cpus-common.c
index 0287018dc4..eecd63029a 100644
--- a/cpus-common.c
+++ b/cpus-common.c
@@ -135,6 +135,11 @@ void run_on_cpu(CPUState *cpu, run_on_cpu_func func,
run_on_cpu_data data)
return;
}
+ /* We are going to sleep on the CPU lock, so release the BQL */
+ if (has_bql) {
+ qemu_mutex_unlock_iothread();
+ }
+
wi.func = func;
wi.data = data;
wi.done = false;
@@ -143,21 +148,6 @@ void run_on_cpu(CPUState *cpu, run_on_cpu_func func,
run_on_cpu_data data)
cpu_mutex_lock(cpu);
queue_work_on_cpu_locked(cpu, &wi);
-
- /*
- * We are going to sleep on the CPU lock, so release the BQL.
- *
- * During the transition to per-CPU locks, we release the BQL _after_
- * having kicked the destination CPU (from queue_work_on_cpu_locked above).
- * This makes sure that the enqueued work will be seen by the CPU
- * after being woken up from the kick, since the CPU sleeps on the BQL.
- * Once we complete the transition to per-CPU locks, we will release
- * the BQL earlier in this function.
- */
- if (has_bql) {
- qemu_mutex_unlock_iothread();
- }
-
while (!atomic_mb_read(&wi.done)) {
CPUState *self_cpu = current_cpu;
--
2.17.1
- [PATCH v10 61/73] cpu: call .cpu_has_work with the CPU lock held, (continued)
- [PATCH v10 61/73] cpu: call .cpu_has_work with the CPU lock held, Robert Foley, 2020/06/17
- [PATCH v10 64/73] mips: convert to cpu_has_work_with_iothread_lock, Robert Foley, 2020/06/17
- [PATCH v10 66/73] riscv: convert to cpu_has_work_with_iothread_lock, Robert Foley, 2020/06/17
- [PATCH v10 68/73] xtensa: convert to cpu_has_work_with_iothread_lock, Robert Foley, 2020/06/17
- [PATCH v10 65/73] s390x: convert to cpu_has_work_with_iothread_lock, Robert Foley, 2020/06/17
- [PATCH v10 69/73] cpu: rename all_cpu_threads_idle to qemu_tcg_rr_all_cpu_threads_idle, Robert Foley, 2020/06/17
- [PATCH v10 70/73] cpu: protect CPU state with cpu->lock instead of the BQL, Robert Foley, 2020/06/17
- [PATCH v10 73/73] cputlb: queue async flush jobs without the BQL, Robert Foley, 2020/06/17
- [PATCH v10 72/73] cpu: add async_run_on_cpu_no_bql, Robert Foley, 2020/06/17
- [PATCH v10 67/73] sparc: convert to cpu_has_work_with_iothread_lock, Robert Foley, 2020/06/17
- [PATCH v10 71/73] cpus-common: release BQL earlier in run_on_cpu,
Robert Foley <=
- Re: [PATCH v10 00/73] per-CPU locks, no-reply, 2020/06/17