From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by dpdk.org (Postfix) with ESMTP id D8EB7160 for ; Mon, 8 Oct 2018 11:12:03 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 472157A9; Mon, 8 Oct 2018 02:12:03 -0700 (PDT) Received: from localhost.localdomain (unknown [10.171.20.31]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id A1D7B3F5D3; Mon, 8 Oct 2018 02:12:01 -0700 (PDT) From: Phil Yang To: dev@dpdk.org Cc: jerin.jacob@caviumnetworks.com, Gavin.Hu@arm.com, Honnappa.Nagarahalli@arm.com, Ola.Liljedahl@arm.com, ferruh.yigit@intel.com, phil.yang@arm.com Date: Mon, 8 Oct 2018 17:11:46 +0800 Message-Id: <1538989906-8349-4-git-send-email-phil.yang@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1538989906-8349-1-git-send-email-phil.yang@arm.com> References: <1537364560-4124-1-git-send-email-phil.yang@arm.com> <1538989906-8349-1-git-send-email-phil.yang@arm.com> Subject: [dpdk-dev] [PATCH v3 4/4] kni: introduce c11 atomic into kni fifo synchronization X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 08 Oct 2018 09:12:04 -0000 Syncing the values by adding c11 atomic memory barriers to make sure the values being synced before updating fifo_write and fifo_read. Signed-off-by: Phil Yang Reviewed-by: Honnappa Nagarahalli Reviewed-by: Gavin Hu Reviewed-by: Ola Liljedahl --- .../linuxapp/eal/include/exec-env/rte_kni_common.h | 5 +++ lib/librte_kni/rte_kni_fifo.h | 47 +++++++++++++++++----- 2 files changed, 41 insertions(+), 11 deletions(-) diff --git a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h index 58e8533..5afa087 100644 --- a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h +++ b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h @@ -55,8 +55,13 @@ struct rte_kni_request { * Writing should never overwrite the read position */ struct rte_kni_fifo { +#ifdef RTE_USE_C11_MEM_MODEL + unsigned write; /**< Next position to be written*/ + unsigned read; /**< Next position to be read */ +#else volatile unsigned write; /**< Next position to be written*/ volatile unsigned read; /**< Next position to be read */ +#endif unsigned len; /**< Circular buffer length */ unsigned elem_size; /**< Pointer size - for 32/64 bit OS */ void *volatile buffer[]; /**< The buffer contains mbuf pointers */ diff --git a/lib/librte_kni/rte_kni_fifo.h b/lib/librte_kni/rte_kni_fifo.h index 70ac14e..83d31b6 100644 --- a/lib/librte_kni/rte_kni_fifo.h +++ b/lib/librte_kni/rte_kni_fifo.h @@ -5,6 +5,36 @@ /** + * @internal when c11 memory model enabled use c11 atomic memory barrier. + * when under non c11 memory model use rte_smp_* memory barrier. + * + * @param src + * Pointer to the source data. + * @param dst + * Pointer to the destination data. + * @param value + * Data value. + */ +#ifdef RTE_USE_C11_MEM_MODEL +#define __KNI_LOAD_ACQUIRE(src) ({ \ + __atomic_load_n((src), __ATOMIC_ACQUIRE); \ + }) +#define __KNI_STORE_RELEASE(dst, value) do { \ + __atomic_store_n((dst), value, __ATOMIC_RELEASE); \ + } while(0) +#else +#define __KNI_LOAD_ACQUIRE(src) ({ \ + typeof (*(src)) val = *(src); \ + rte_smp_rmb(); \ + val; \ + }) +#define __KNI_STORE_RELEASE(dst, value) do { \ + *(dst) = value; \ + rte_smp_wmb(); \ + } while(0) +#endif + +/** * Initializes the kni fifo structure */ static void @@ -29,8 +59,7 @@ kni_fifo_put(struct rte_kni_fifo *fifo, void **data, unsigned num) unsigned i = 0; unsigned fifo_write = fifo->write; unsigned new_write = fifo_write; - rte_smp_rmb(); - unsigned fifo_read = fifo->read; + unsigned fifo_read = __KNI_LOAD_ACQUIRE(&fifo->read); for (i = 0; i < num; i++) { new_write = (new_write + 1) & (fifo->len - 1); @@ -40,8 +69,7 @@ kni_fifo_put(struct rte_kni_fifo *fifo, void **data, unsigned num) fifo->buffer[fifo_write] = data[i]; fifo_write = new_write; } - rte_smp_wmb(); - fifo->write = fifo_write; + __KNI_STORE_RELEASE(&fifo->write, fifo_write); return i; } @@ -53,8 +81,7 @@ kni_fifo_get(struct rte_kni_fifo *fifo, void **data, unsigned num) { unsigned i = 0; unsigned new_read = fifo->read; - rte_smp_rmb(); - unsigned fifo_write = fifo->write; + unsigned fifo_write = __KNI_LOAD_ACQUIRE(&fifo->write); for (i = 0; i < num; i++) { if (new_read == fifo_write) @@ -63,8 +90,7 @@ kni_fifo_get(struct rte_kni_fifo *fifo, void **data, unsigned num) data[i] = fifo->buffer[new_read]; new_read = (new_read + 1) & (fifo->len - 1); } - rte_smp_rmb(); - fifo->read = new_read; + __KNI_STORE_RELEASE(&fifo->read, new_read); return i; } @@ -74,8 +100,7 @@ kni_fifo_get(struct rte_kni_fifo *fifo, void **data, unsigned num) static inline uint32_t kni_fifo_count(struct rte_kni_fifo *fifo) { - unsigned fifo_write = fifo->write; - rte_smp_rmb(); - unsigned fifo_read = fifo->read; + unsigned fifo_write = __KNI_LOAD_ACQUIRE(&fifo->write); + unsigned fifo_read = __KNI_LOAD_ACQUIRE(&fifo->read); return (fifo->len + fifo_write - fifo_read) & (fifo->len - 1); } -- 2.7.4