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[204.195.112.43]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-896c42b06e9sm187909b3a.42.2026.10.08.16.37.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 08 Oct 2026 16:37:38 -0700 (PDT) From: Stephen Hemminger To: dev@dpdk.org Cc: Stephen Hemminger , Harman Kalra Subject: [PATCH v3 21/29] common/octeontx: remove redundant barrier in mbox Date: Thu, 8 Oct 2026 16:35:14 -0700 Message-ID: <20261008233649.1260843-22-stephen@networkplumber.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261008233649.1260843-1-stephen@networkplumber.org> References: <20260729175715.165120-1-stephen@networkplumber.org> <20261008233649.1260843-1-stephen@networkplumber.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org The SMP write barrier between writing the mailbox header and ringing the mailbox register is redundant: rte_write64() begins with rte_io_wmb(), which already orders the header write before the trigger, and does so against the device rather than only within the inner shareable domain. Signed-off-by: Stephen Hemminger --- drivers/common/octeontx/octeontx_mbox.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/common/octeontx/octeontx_mbox.c b/drivers/common/octeontx/octeontx_mbox.c index 9e0bbf453f..8b0da3a98e 100644 --- a/drivers/common/octeontx/octeontx_mbox.c +++ b/drivers/common/octeontx/octeontx_mbox.c @@ -113,8 +113,10 @@ mbox_send_request(struct mbox *m, struct octeontx_mbox_hdr *hdr, /* Write the msg header */ rte_write64(new_hdr.u64, ram_mbox_hdr); - rte_smp_wmb(); - /* Notify PF about the new msg - write to MBOX reg generates PF IRQ */ + /* Notify PF about the new msg - write to MBOX reg generates PF IRQ. + * rte_write64() issues rte_io_wmb() which orders the header write + * before the trigger; no separate barrier is needed. + */ rte_write64(0, m->reg); } -- 2.53.0