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Fri, 28 Apr 2023 03:17:37 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ6FktJaAGE40caFUd8g4qI52GCYnLpji+iN7DVzduBKljo2WSveb2KJU30mvG2c6xX9jHNUVw== X-Received: by 2002:a05:600c:2281:b0:3f1:72db:454c with SMTP id 1-20020a05600c228100b003f172db454cmr3732806wmf.19.1682677057000; Fri, 28 Apr 2023 03:17:37 -0700 (PDT) From: Paolo Bonzini To: qemu-devel@nongnu.org Cc: richard.henderson@linaro.org Subject: [PATCH] cpus-common: stop using mb_set/mb_read Date: Fri, 28 Apr 2023 12:17:35 +0200 Message-Id: <20230428101735.130779-1-pbonzini@redhat.com> X-Mailer: git-send-email 2.40.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -22 X-Spam_score: -2.3 X-Spam_bar: -- X-Spam_report: (-2.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.171, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1682677128120100003 Content-Type: text/plain; charset="utf-8" Use a store-release at the end of the work item, and a load-acquire when waiting for the item to be completed. This is the standard message passing pattern and is both enough and clearer than mb_read/mb_set. Signed-off-by: Paolo Bonzini Reviewed-by: Richard Henderson --- cpus-common.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/cpus-common.c b/cpus-common.c index b0047e456f93..a53716deb437 100644 --- a/cpus-common.c +++ b/cpus-common.c @@ -157,7 +157,7 @@ void do_run_on_cpu(CPUState *cpu, run_on_cpu_func func,= run_on_cpu_data data, wi.exclusive =3D false; =20 queue_work_on_cpu(cpu, &wi); - while (!qatomic_mb_read(&wi.done)) { + while (!qatomic_load_acquire(&wi.done)) { CPUState *self_cpu =3D current_cpu; =20 qemu_cond_wait(&qemu_work_cond, mutex); @@ -363,7 +363,7 @@ void process_queued_cpu_work(CPUState *cpu) if (wi->free) { g_free(wi); } else { - qatomic_mb_set(&wi->done, true); + qatomic_store_release(&wi->done, true); } } qemu_mutex_unlock(&cpu->work_mutex); --=20 2.40.0