From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id 6124EA2EFC for ; Tue, 15 Oct 2019 11:29:10 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 0CEE01EAEA; Tue, 15 Oct 2019 11:29:06 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by dpdk.org (Postfix) with ESMTP id E88751EAB1; Tue, 15 Oct 2019 11:28:59 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3555E28; Tue, 15 Oct 2019 02:28:59 -0700 (PDT) Received: from net-arm-c2400-02.shanghai.arm.com (net-arm-c2400-02.shanghai.arm.com [10.169.40.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id E846D3F718; Tue, 15 Oct 2019 02:28:56 -0700 (PDT) From: Ruifeng Wang To: david.hunt@intel.com Cc: dev@dpdk.org, hkalra@marvell.com, gavin.hu@arm.com, honnappa.nagarahalli@arm.com, nd@arm.com, Ruifeng Wang , stable@dpdk.org Date: Tue, 15 Oct 2019 17:28:25 +0800 Message-Id: <20191015092826.13002-2-ruifeng.wang@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191015092826.13002-1-ruifeng.wang@arm.com> References: <20191008095524.1585-1-ruifeng.wang@arm.com> <20191015092826.13002-1-ruifeng.wang@arm.com> Subject: [dpdk-dev] [PATCH v3 1/2] lib/distributor: fix deadlock issue for aarch64 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: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Distributor and worker threads rely on data structs in cache line for synchronization. The shared data structs were not protected. This caused deadlock issue on weaker memory ordering platforms as aarch64. Fix this issue by adding memory barriers to ensure synchronization among cores. Bugzilla ID: 342 Fixes: 775003ad2f96 ("distributor: add new burst-capable library") Cc: stable@dpdk.org Signed-off-by: Ruifeng Wang Reviewed-by: Gavin Hu --- lib/librte_distributor/meson.build | 5 ++ lib/librte_distributor/rte_distributor.c | 68 ++++++++++++++------ lib/librte_distributor/rte_distributor_v20.c | 59 ++++++++++++----- 3 files changed, 97 insertions(+), 35 deletions(-) diff --git a/lib/librte_distributor/meson.build b/lib/librte_distributor/meson.build index dba7e3b2a..26577dbc1 100644 --- a/lib/librte_distributor/meson.build +++ b/lib/librte_distributor/meson.build @@ -9,3 +9,8 @@ else endif headers = files('rte_distributor.h') deps += ['mbuf'] + +# for clang 32-bit compiles we need libatomic for 64-bit atomic ops +if cc.get_id() == 'clang' and dpdk_conf.get('RTE_ARCH_64') == false + ext_deps += cc.find_library('atomic') +endif diff --git a/lib/librte_distributor/rte_distributor.c b/lib/librte_distributor/rte_distributor.c index 21eb1fb0a..0a03625c9 100644 --- a/lib/librte_distributor/rte_distributor.c +++ b/lib/librte_distributor/rte_distributor.c @@ -49,8 +49,11 @@ rte_distributor_request_pkt_v1705(struct rte_distributor *d, } retptr64 = &(buf->retptr64[0]); - /* Spin while handshake bits are set (scheduler clears it) */ - while (unlikely(*retptr64 & RTE_DISTRIB_GET_BUF)) { + /* Spin while handshake bits are set (scheduler clears it). + * Sync with worker on GET_BUF flag. + */ + while (unlikely(__atomic_load_n(retptr64, __ATOMIC_ACQUIRE) + & RTE_DISTRIB_GET_BUF)) { rte_pause(); uint64_t t = rte_rdtsc()+100; @@ -75,8 +78,10 @@ rte_distributor_request_pkt_v1705(struct rte_distributor *d, /* * Finally, set the GET_BUF to signal to distributor that cache * line is ready for processing + * Sync with distributor to release retptrs */ - *retptr64 |= RTE_DISTRIB_GET_BUF; + __atomic_store_n(retptr64, *retptr64 | RTE_DISTRIB_GET_BUF, + __ATOMIC_RELEASE); } BIND_DEFAULT_SYMBOL(rte_distributor_request_pkt, _v1705, 17.05); MAP_STATIC_SYMBOL(void rte_distributor_request_pkt(struct rte_distributor *d, @@ -98,8 +103,11 @@ rte_distributor_poll_pkt_v1705(struct rte_distributor *d, return (pkts[0]) ? 1 : 0; } - /* If bit is set, return */ - if (buf->bufptr64[0] & RTE_DISTRIB_GET_BUF) + /* If bit is set, return + * Sync with distributor to acquire bufptrs + */ + if (__atomic_load_n(&(buf->bufptr64[0]), __ATOMIC_ACQUIRE) + & RTE_DISTRIB_GET_BUF) return -1; /* since bufptr64 is signed, this should be an arithmetic shift */ @@ -114,8 +122,10 @@ rte_distributor_poll_pkt_v1705(struct rte_distributor *d, * so now we've got the contents of the cacheline into an array of * mbuf pointers, so toggle the bit so scheduler can start working * on the next cacheline while we're working. + * Sync with distributor on GET_BUF flag. Release bufptrs. */ - buf->bufptr64[0] |= RTE_DISTRIB_GET_BUF; + __atomic_store_n(&(buf->bufptr64[0]), + buf->bufptr64[0] | RTE_DISTRIB_GET_BUF, __ATOMIC_RELEASE); return count; } @@ -174,6 +184,8 @@ rte_distributor_return_pkt_v1705(struct rte_distributor *d, return -EINVAL; } + /* Sync with distributor to acquire retptrs */ + __atomic_thread_fence(__ATOMIC_ACQUIRE); for (i = 0; i < RTE_DIST_BURST_SIZE; i++) /* Switch off the return bit first */ buf->retptr64[i] &= ~RTE_DISTRIB_RETURN_BUF; @@ -182,8 +194,11 @@ rte_distributor_return_pkt_v1705(struct rte_distributor *d, buf->retptr64[i] = (((int64_t)(uintptr_t)oldpkt[i]) << RTE_DISTRIB_FLAG_BITS) | RTE_DISTRIB_RETURN_BUF; - /* set the GET_BUF but even if we got no returns */ - buf->retptr64[0] |= RTE_DISTRIB_GET_BUF; + /* set the GET_BUF but even if we got no returns. + * Sync with distributor on GET_BUF flag. Release retptrs. + */ + __atomic_store_n(&(buf->retptr64[0]), + buf->retptr64[0] | RTE_DISTRIB_GET_BUF, __ATOMIC_RELEASE); return 0; } @@ -273,7 +288,9 @@ handle_returns(struct rte_distributor *d, unsigned int wkr) unsigned int count = 0; unsigned int i; - if (buf->retptr64[0] & RTE_DISTRIB_GET_BUF) { + /* Sync on GET_BUF flag. Acquire retptrs. */ + if (__atomic_load_n(&(buf->retptr64[0]), __ATOMIC_ACQUIRE) + & RTE_DISTRIB_GET_BUF) { for (i = 0; i < RTE_DIST_BURST_SIZE; i++) { if (buf->retptr64[i] & RTE_DISTRIB_RETURN_BUF) { oldbuf = ((uintptr_t)(buf->retptr64[i] >> @@ -286,8 +303,10 @@ handle_returns(struct rte_distributor *d, unsigned int wkr) } d->returns.start = ret_start; d->returns.count = ret_count; - /* Clear for the worker to populate with more returns */ - buf->retptr64[0] = 0; + /* Clear for the worker to populate with more returns. + * Sync with distributor on GET_BUF flag. Release retptrs. + */ + __atomic_store_n(&(buf->retptr64[0]), 0, __ATOMIC_RELEASE); } return count; } @@ -307,7 +326,9 @@ release(struct rte_distributor *d, unsigned int wkr) struct rte_distributor_buffer *buf = &(d->bufs[wkr]); unsigned int i; - while (!(d->bufs[wkr].bufptr64[0] & RTE_DISTRIB_GET_BUF)) + /* Sync with worker on GET_BUF flag */ + while (!(__atomic_load_n(&(d->bufs[wkr].bufptr64[0]), __ATOMIC_ACQUIRE) + & RTE_DISTRIB_GET_BUF)) rte_pause(); handle_returns(d, wkr); @@ -327,8 +348,11 @@ release(struct rte_distributor *d, unsigned int wkr) d->backlog[wkr].count = 0; - /* Clear the GET bit */ - buf->bufptr64[0] &= ~RTE_DISTRIB_GET_BUF; + /* Clear the GET bit. + * Sync with worker on GET_BUF flag. Release bufptrs. + */ + __atomic_store_n(&(buf->bufptr64[0]), + buf->bufptr64[0] & ~RTE_DISTRIB_GET_BUF, __ATOMIC_RELEASE); return buf->count; } @@ -355,7 +379,9 @@ rte_distributor_process_v1705(struct rte_distributor *d, if (unlikely(num_mbufs == 0)) { /* Flush out all non-full cache-lines to workers. */ for (wid = 0 ; wid < d->num_workers; wid++) { - if (d->bufs[wid].bufptr64[0] & RTE_DISTRIB_GET_BUF) { + /* Sync with worker on GET_BUF flag. */ + if (__atomic_load_n(&(d->bufs[wid].bufptr64[0]), + __ATOMIC_ACQUIRE) & RTE_DISTRIB_GET_BUF) { release(d, wid); handle_returns(d, wid); } @@ -367,7 +393,9 @@ rte_distributor_process_v1705(struct rte_distributor *d, uint16_t matches[RTE_DIST_BURST_SIZE]; unsigned int pkts; - if (d->bufs[wkr].bufptr64[0] & RTE_DISTRIB_GET_BUF) + /* Sync with worker on GET_BUF flag. */ + if (__atomic_load_n(&(d->bufs[wkr].bufptr64[0]), + __ATOMIC_ACQUIRE) & RTE_DISTRIB_GET_BUF) d->bufs[wkr].count = 0; if ((num_mbufs - next_idx) < RTE_DIST_BURST_SIZE) @@ -465,7 +493,9 @@ rte_distributor_process_v1705(struct rte_distributor *d, /* Flush out all non-full cache-lines to workers. */ for (wid = 0 ; wid < d->num_workers; wid++) - if ((d->bufs[wid].bufptr64[0] & RTE_DISTRIB_GET_BUF)) + /* Sync with worker on GET_BUF flag. */ + if ((__atomic_load_n(&(d->bufs[wid].bufptr64[0]), + __ATOMIC_ACQUIRE) & RTE_DISTRIB_GET_BUF)) release(d, wid); return num_mbufs; @@ -574,7 +604,9 @@ rte_distributor_clear_returns_v1705(struct rte_distributor *d) /* throw away returns, so workers can exit */ for (wkr = 0; wkr < d->num_workers; wkr++) - d->bufs[wkr].retptr64[0] = 0; + /* Sync with worker. Release retptrs. */ + __atomic_store_n(&(d->bufs[wkr].retptr64[0]), 0, + __ATOMIC_RELEASE); } BIND_DEFAULT_SYMBOL(rte_distributor_clear_returns, _v1705, 17.05); MAP_STATIC_SYMBOL(void rte_distributor_clear_returns(struct rte_distributor *d), diff --git a/lib/librte_distributor/rte_distributor_v20.c b/lib/librte_distributor/rte_distributor_v20.c index cdc0969a8..ef6d5cb4b 100644 --- a/lib/librte_distributor/rte_distributor_v20.c +++ b/lib/librte_distributor/rte_distributor_v20.c @@ -34,9 +34,12 @@ rte_distributor_request_pkt_v20(struct rte_distributor_v20 *d, union rte_distributor_buffer_v20 *buf = &d->bufs[worker_id]; int64_t req = (((int64_t)(uintptr_t)oldpkt) << RTE_DISTRIB_FLAG_BITS) | RTE_DISTRIB_GET_BUF; - while (unlikely(buf->bufptr64 & RTE_DISTRIB_FLAGS_MASK)) + while (unlikely(__atomic_load_n(&buf->bufptr64, __ATOMIC_RELAXED) + & RTE_DISTRIB_FLAGS_MASK)) rte_pause(); - buf->bufptr64 = req; + + /* Sync with distributor on GET_BUF flag. */ + __atomic_store_n(&(buf->bufptr64), req, __ATOMIC_RELEASE); } VERSION_SYMBOL(rte_distributor_request_pkt, _v20, 2.0); @@ -45,7 +48,9 @@ rte_distributor_poll_pkt_v20(struct rte_distributor_v20 *d, unsigned worker_id) { union rte_distributor_buffer_v20 *buf = &d->bufs[worker_id]; - if (buf->bufptr64 & RTE_DISTRIB_GET_BUF) + /* Sync with distributor. Acquire bufptr64. */ + if (__atomic_load_n(&buf->bufptr64, __ATOMIC_ACQUIRE) + & RTE_DISTRIB_GET_BUF) return NULL; /* since bufptr64 is signed, this should be an arithmetic shift */ @@ -73,7 +78,8 @@ rte_distributor_return_pkt_v20(struct rte_distributor_v20 *d, union rte_distributor_buffer_v20 *buf = &d->bufs[worker_id]; uint64_t req = (((int64_t)(uintptr_t)oldpkt) << RTE_DISTRIB_FLAG_BITS) | RTE_DISTRIB_RETURN_BUF; - buf->bufptr64 = req; + /* Sync with distributor on RETURN_BUF flag. */ + __atomic_store_n(&(buf->bufptr64), req, __ATOMIC_RELEASE); return 0; } VERSION_SYMBOL(rte_distributor_return_pkt, _v20, 2.0); @@ -117,7 +123,8 @@ handle_worker_shutdown(struct rte_distributor_v20 *d, unsigned int wkr) { d->in_flight_tags[wkr] = 0; d->in_flight_bitmask &= ~(1UL << wkr); - d->bufs[wkr].bufptr64 = 0; + /* Sync with worker. Release bufptr64. */ + __atomic_store_n(&(d->bufs[wkr].bufptr64), 0, __ATOMIC_RELEASE); if (unlikely(d->backlog[wkr].count != 0)) { /* On return of a packet, we need to move the * queued packets for this core elsewhere. @@ -161,17 +168,23 @@ process_returns(struct rte_distributor_v20 *d) ret_count = d->returns.count; for (wkr = 0; wkr < d->num_workers; wkr++) { - - const int64_t data = d->bufs[wkr].bufptr64; uintptr_t oldbuf = 0; + /* Sync with worker. Acquire bufptr64. */ + const int64_t data = __atomic_load_n(&(d->bufs[wkr].bufptr64), + __ATOMIC_ACQUIRE); if (data & RTE_DISTRIB_GET_BUF) { flushed++; if (d->backlog[wkr].count) - d->bufs[wkr].bufptr64 = - backlog_pop(&d->backlog[wkr]); + /* Sync with worker. Release bufptr64. */ + __atomic_store_n(&(d->bufs[wkr].bufptr64), + backlog_pop(&d->backlog[wkr]), + __ATOMIC_RELEASE); else { - d->bufs[wkr].bufptr64 = RTE_DISTRIB_GET_BUF; + /* Sync with worker on GET_BUF flag. */ + __atomic_store_n(&(d->bufs[wkr].bufptr64), + RTE_DISTRIB_GET_BUF, + __ATOMIC_RELEASE); d->in_flight_tags[wkr] = 0; d->in_flight_bitmask &= ~(1UL << wkr); } @@ -207,9 +220,10 @@ rte_distributor_process_v20(struct rte_distributor_v20 *d, return process_returns(d); while (next_idx < num_mbufs || next_mb != NULL) { - - int64_t data = d->bufs[wkr].bufptr64; uintptr_t oldbuf = 0; + /* Sync with worker. Acquire bufptr64. */ + int64_t data = __atomic_load_n(&(d->bufs[wkr].bufptr64), + __ATOMIC_ACQUIRE); if (!next_mb) { next_mb = mbufs[next_idx++]; @@ -255,11 +269,16 @@ rte_distributor_process_v20(struct rte_distributor_v20 *d, (d->backlog[wkr].count || next_mb)) { if (d->backlog[wkr].count) - d->bufs[wkr].bufptr64 = - backlog_pop(&d->backlog[wkr]); + /* Sync with worker. Release bufptr64. */ + __atomic_store_n(&(d->bufs[wkr].bufptr64), + backlog_pop(&d->backlog[wkr]), + __ATOMIC_RELEASE); else { - d->bufs[wkr].bufptr64 = next_value; + /* Sync with worker. Release bufptr64. */ + __atomic_store_n(&(d->bufs[wkr].bufptr64), + next_value, + __ATOMIC_RELEASE); d->in_flight_tags[wkr] = new_tag; d->in_flight_bitmask |= (1UL << wkr); next_mb = NULL; @@ -280,13 +299,19 @@ rte_distributor_process_v20(struct rte_distributor_v20 *d, * if they are ready */ for (wkr = 0; wkr < d->num_workers; wkr++) if (d->backlog[wkr].count && - (d->bufs[wkr].bufptr64 & RTE_DISTRIB_GET_BUF)) { + /* Sync with worker. Acquire bufptr64. */ + (__atomic_load_n(&(d->bufs[wkr].bufptr64), + __ATOMIC_ACQUIRE) & RTE_DISTRIB_GET_BUF)) { int64_t oldbuf = d->bufs[wkr].bufptr64 >> RTE_DISTRIB_FLAG_BITS; + store_return(oldbuf, d, &ret_start, &ret_count); - d->bufs[wkr].bufptr64 = backlog_pop(&d->backlog[wkr]); + /* Sync with worker. Release bufptr64. */ + __atomic_store_n(&(d->bufs[wkr].bufptr64), + backlog_pop(&d->backlog[wkr]), + __ATOMIC_RELEASE); } d->returns.start = ret_start; -- 2.17.1