Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751494AbcLEEZM (ORCPT ); Sun, 4 Dec 2016 23:25:12 -0500 Received: from smtp-fw-9101.amazon.com ([207.171.184.25]:6312 "EHLO smtp-fw-9101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751168AbcLEEZL (ORCPT ); Sun, 4 Dec 2016 23:25:11 -0500 X-IronPort-AV: E=Sophos;i="5.33,302,1477958400"; d="scan'208";a="663428630" Date: Sun, 4 Dec 2016 20:24:35 -0800 From: Matt Wilson To: Netanel Belgazal CC: , , , , , , , , , Subject: Re: [PATCH V2 net 07/20] net/ena: refactor ena_get_stats64 to be atomic context safe Message-ID: <20161205042435.GG4310@u54ee753d2d1854bda401.ant.amazon.com> References: <1480857578-5065-1-git-send-email-netanel@annapurnalabs.com> <1480857578-5065-8-git-send-email-netanel@annapurnalabs.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <1480857578-5065-8-git-send-email-netanel@annapurnalabs.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5096 Lines: 146 On Sun, Dec 04, 2016 at 03:19:25PM +0200, Netanel Belgazal wrote: > ndo_get_stat64 can be called from atomic context. > However the current implementation sends an admin command to retrieve > the statistics from the device. > This admin commands uses sleep. Suggest some comment edits: ndo_get_stat64() can be called from atomic context, but the current implementation sends an admin command to retrieve the statistics from the device. This admin command can sleep. > Refactor the implementation of ena_get_stats64 to take the > {rx,tx}bytes/cnt from the driver's inner counters > and to take the rx drops counter > from the asynchronous keep alive (heart bit) event. This patch re-factors the implementation of ena_get_stats64() to use the {rx,tx}bytes/count from the driver's inner counters, and to obtain the rx drop counter from the asynchronous keep alive (heart bit) event. --msw > Signed-off-by: Netanel Belgazal > --- > drivers/net/ethernet/amazon/ena/ena_admin_defs.h | 8 ++++ > drivers/net/ethernet/amazon/ena/ena_netdev.c | 57 +++++++++++++++++------- > drivers/net/ethernet/amazon/ena/ena_netdev.h | 1 + > 3 files changed, 51 insertions(+), 15 deletions(-) > > diff --git a/drivers/net/ethernet/amazon/ena/ena_admin_defs.h b/drivers/net/ethernet/amazon/ena/ena_admin_defs.h > index f48c886..6d70bf5 100644 > --- a/drivers/net/ethernet/amazon/ena/ena_admin_defs.h > +++ b/drivers/net/ethernet/amazon/ena/ena_admin_defs.h > @@ -873,6 +873,14 @@ struct ena_admin_aenq_link_change_desc { > u32 flags; > }; > > +struct ena_admin_aenq_keep_alive_desc { > + struct ena_admin_aenq_common_desc aenq_common_desc; > + > + u32 rx_drops_low; > + > + u32 rx_drops_high; > +}; > + > struct ena_admin_ena_mmio_req_read_less_resp { > u16 req_id; > > diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c > index ad5f78f..962ffb5 100644 > --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c > +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c > @@ -2176,28 +2176,46 @@ static struct rtnl_link_stats64 *ena_get_stats64(struct net_device *netdev, > struct rtnl_link_stats64 *stats) > { > struct ena_adapter *adapter = netdev_priv(netdev); > - struct ena_admin_basic_stats ena_stats; > - int rc; > + struct ena_ring *rx_ring, *tx_ring; > + unsigned int start; > + u64 rx_drops; > + int i; > > if (!test_bit(ENA_FLAG_DEV_UP, &adapter->flags)) > return NULL; > > - rc = ena_com_get_dev_basic_stats(adapter->ena_dev, &ena_stats); > - if (rc) > - return NULL; > + for (i = 0; i < adapter->num_queues; i++) { > + u64 bytes, packets; > + > + tx_ring = &adapter->tx_ring[i]; > + > + do { > + start = u64_stats_fetch_begin_irq(&tx_ring->syncp); > + packets = tx_ring->tx_stats.cnt; > + bytes = tx_ring->tx_stats.bytes; > + } while (u64_stats_fetch_retry_irq(&tx_ring->syncp, start)); > + > + stats->tx_packets += packets; > + stats->tx_bytes += bytes; > > - stats->tx_bytes = ((u64)ena_stats.tx_bytes_high << 32) | > - ena_stats.tx_bytes_low; > - stats->rx_bytes = ((u64)ena_stats.rx_bytes_high << 32) | > - ena_stats.rx_bytes_low; > + rx_ring = &adapter->rx_ring[i]; > + > + do { > + start = u64_stats_fetch_begin_irq(&rx_ring->syncp); > + packets = rx_ring->rx_stats.cnt; > + bytes = rx_ring->rx_stats.bytes; > + } while (u64_stats_fetch_retry_irq(&rx_ring->syncp, start)); > > - stats->rx_packets = ((u64)ena_stats.rx_pkts_high << 32) | > - ena_stats.rx_pkts_low; > - stats->tx_packets = ((u64)ena_stats.tx_pkts_high << 32) | > - ena_stats.tx_pkts_low; > + stats->rx_packets += packets; > + stats->rx_bytes += bytes; > + } > + > + do { > + start = u64_stats_fetch_begin_irq(&adapter->syncp); > + rx_drops = adapter->dev_stats.rx_drops; > + } while (u64_stats_fetch_retry_irq(&adapter->syncp, start)); > > - stats->rx_dropped = ((u64)ena_stats.rx_drops_high << 32) | > - ena_stats.rx_drops_low; > + stats->rx_dropped = rx_drops; > > stats->multicast = 0; > stats->collisions = 0; > @@ -3221,8 +3239,17 @@ static void ena_keep_alive_wd(void *adapter_data, > struct ena_admin_aenq_entry *aenq_e) > { > struct ena_adapter *adapter = (struct ena_adapter *)adapter_data; > + struct ena_admin_aenq_keep_alive_desc *desc; > + u64 rx_drops; > > + desc = (struct ena_admin_aenq_keep_alive_desc *)aenq_e; > adapter->last_keep_alive_jiffies = jiffies; > + > + rx_drops = ((u64)desc->rx_drops_high << 32) | desc->rx_drops_low; > + > + u64_stats_update_begin(&adapter->syncp); > + adapter->dev_stats.rx_drops = rx_drops; > + u64_stats_update_end(&adapter->syncp); > } > > static void ena_notification(void *adapter_data, > diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.h b/drivers/net/ethernet/amazon/ena/ena_netdev.h > index 69d7e9e..f0ddc11 100644 > --- a/drivers/net/ethernet/amazon/ena/ena_netdev.h > +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.h > @@ -241,6 +241,7 @@ struct ena_stats_dev { > u64 interface_up; > u64 interface_down; > u64 admin_q_pause; > + u64 rx_drops; > }; > > enum ena_flags_t {