From patchwork Tue Sep 23 15:02:29 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michal Jastrzebski X-Patchwork-Id: 470 Return-Path: X-Original-To: patchwork@dpdk.org Delivered-To: patchwork@dpdk.org Received: from [92.243.14.124] (localhost [IPv6:::1]) by dpdk.org (Postfix) with ESMTP id 7A7D55920; Tue, 23 Sep 2014 16:58:10 +0200 (CEST) Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by dpdk.org (Postfix) with ESMTP id 1B5E558FE for ; Tue, 23 Sep 2014 16:58:07 +0200 (CEST) Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga102.jf.intel.com with ESMTP; 23 Sep 2014 07:57:45 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,580,1406617200"; d="scan'208";a="607211479" Received: from irvmail001.ir.intel.com ([163.33.26.43]) by orsmga002.jf.intel.com with ESMTP; 23 Sep 2014 08:02:33 -0700 Received: from sivswdev01.ir.intel.com (sivswdev01.ir.intel.com [10.237.217.45]) by irvmail001.ir.intel.com (8.14.3/8.13.6/MailSET/Hub) with ESMTP id s8NF2VJx022525; Tue, 23 Sep 2014 16:02:31 +0100 Received: from sivswdev01.ir.intel.com (localhost [127.0.0.1]) by sivswdev01.ir.intel.com with ESMTP id s8NF2Woq000754; Tue, 23 Sep 2014 16:02:32 +0100 Received: (from mkjastrx@localhost) by sivswdev01.ir.intel.com with id s8NF2VBA000747; Tue, 23 Sep 2014 16:02:31 +0100 From: Michal Jastrzebski To: dev@dpdk.org Date: Tue, 23 Sep 2014 16:02:29 +0100 Message-Id: <1411484549-711-1-git-send-email-michalx.k.jastrzebski@intel.com> X-Mailer: git-send-email 1.7.4.1 Subject: [dpdk-dev] [PATCH] Change alarm cancel function to thread-safe. X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" It eliminates a race between threads using rte_alarm_cancel and rte_alarm_set. Signed-off-by: Pawel Wodkowski Reviewed-by: Michal Jastrzebski --- lib/librte_eal/common/include/rte_alarm.h | 3 +- lib/librte_eal/linuxapp/eal/eal_alarm.c | 68 +++++++++++++++++++---------- 2 files changed, 46 insertions(+), 25 deletions(-) diff --git a/lib/librte_eal/common/include/rte_alarm.h b/lib/librte_eal/common/include/rte_alarm.h index d451522..f5f7de4 100644 --- a/lib/librte_eal/common/include/rte_alarm.h +++ b/lib/librte_eal/common/include/rte_alarm.h @@ -76,7 +76,8 @@ typedef void (*rte_eal_alarm_callback)(void *arg); int rte_eal_alarm_set(uint64_t us, rte_eal_alarm_callback cb, void *cb_arg); /** - * Function to cancel an alarm callback which has been registered before. + * Function to cancel an alarm callback which has been registered before. If + * used ouside alarm callback it wait for all callbacks to finish its execution. * * @param cb_fn * alarm callback diff --git a/lib/librte_eal/linuxapp/eal/eal_alarm.c b/lib/librte_eal/linuxapp/eal/eal_alarm.c index 480f0cb..0561dbf 100644 --- a/lib/librte_eal/linuxapp/eal/eal_alarm.c +++ b/lib/librte_eal/linuxapp/eal/eal_alarm.c @@ -69,12 +69,14 @@ struct alarm_entry { struct timeval time; rte_eal_alarm_callback cb_fn; void *cb_arg; - volatile int executing; + volatile uint8_t executing; + volatile pthread_t executing_id; }; static LIST_HEAD(alarm_list, alarm_entry) alarm_list = LIST_HEAD_INITIALIZER(); static rte_spinlock_t alarm_list_lk = RTE_SPINLOCK_INITIALIZER; + static struct rte_intr_handle intr_handle = {.fd = -1 }; static int handler_registered = 0; static void eal_alarm_callback(struct rte_intr_handle *hdl, void *arg); @@ -108,11 +110,14 @@ eal_alarm_callback(struct rte_intr_handle *hdl __rte_unused, (ap->time.tv_sec < now.tv_sec || (ap->time.tv_sec == now.tv_sec && ap->time.tv_usec <= now.tv_usec))){ ap->executing = 1; + ap->executing_id = pthread_self(); rte_spinlock_unlock(&alarm_list_lk); ap->cb_fn(ap->cb_arg); rte_spinlock_lock(&alarm_list_lk); + ap->executing = 0; + LIST_REMOVE(ap, next); rte_free(ap); } @@ -156,7 +161,6 @@ rte_eal_alarm_set(uint64_t us, rte_eal_alarm_callback cb_fn, void *cb_arg) new_alarm->cb_arg = cb_arg; new_alarm->time.tv_usec = (now.tv_usec + us) % US_PER_S; new_alarm->time.tv_sec = now.tv_sec + ((now.tv_usec + us) / US_PER_S); - new_alarm->executing = 0; rte_spinlock_lock(&alarm_list_lk); if (!handler_registered) { @@ -202,34 +206,50 @@ rte_eal_alarm_cancel(rte_eal_alarm_callback cb_fn, void *cb_arg) { struct alarm_entry *ap, *ap_prev; int count = 0; + int executing; if (!cb_fn) return -1; - rte_spinlock_lock(&alarm_list_lk); - /* remove any matches at the start of the list */ - while ((ap = LIST_FIRST(&alarm_list)) != NULL && - cb_fn == ap->cb_fn && ap->executing == 0 && - (cb_arg == (void *)-1 || cb_arg == ap->cb_arg)) { - LIST_REMOVE(ap, next); - rte_free(ap); - count++; - } - ap_prev = ap; - - /* now go through list, removing entries not at start */ - LIST_FOREACH(ap, &alarm_list, next) { - /* this won't be true first time through */ - if (cb_fn == ap->cb_fn && ap->executing == 0 && + do { + executing = 0; + rte_spinlock_lock(&alarm_list_lk); + /* remove any matches at the start of the list */ + while ((ap = LIST_FIRST(&alarm_list)) != NULL && + cb_fn == ap->cb_fn && (cb_arg == (void *)-1 || cb_arg == ap->cb_arg)) { - LIST_REMOVE(ap,next); - rte_free(ap); - count++; - ap = ap_prev; + + if (ap->executing == 0) { + LIST_REMOVE(ap, next); + rte_free(ap); + count++; + } else { + if (pthread_equal(ap->executing_id, pthread_self()) == 0) + executing++; + + break; + } } ap_prev = ap; - } - rte_spinlock_unlock(&alarm_list_lk); + + /* now go through list, removing entries not at start */ + LIST_FOREACH(ap, &alarm_list, next) { + /* this won't be true first time through */ + if (cb_fn == ap->cb_fn && + (cb_arg == (void *)-1 || cb_arg == ap->cb_arg)) { + + if (ap->executing == 0) { + LIST_REMOVE(ap, next); + rte_free(ap); + count++; + ap = ap_prev; + } else if (pthread_equal(ap->executing_id, pthread_self()) == 0) + executing++; + } + ap_prev = ap; + } + rte_spinlock_unlock(&alarm_list_lk); + } while (executing != 0); + return count; } -