From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrei Vagin Subject: Re: [net-next, v6, 6/7] net-sysfs: Add interface for Rx queue(s) map per Tx queue Date: Wed, 4 Jul 2018 00:20:49 -0700 Message-ID: <20180704072048.GA29107@outlook.office365.com> References: <153033282719.8297.790755582693609184.stgit@anamhost.jf.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=koi8-r Cc: netdev@vger.kernel.org, davem@davemloft.net, alexander.h.duyck@intel.com, willemdebruijn.kernel@gmail.com, sridhar.samudrala@intel.com, alexander.duyck@gmail.com, edumazet@google.com, hannes@stressinduktion.org, tom@herbertland.com, tom@quantonium.net To: Amritha Nambiar Return-path: Received: from mail-eopbgr50109.outbound.protection.outlook.com ([40.107.5.109]:50720 "EHLO EUR03-VE1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932479AbeGDHVB (ORCPT ); Wed, 4 Jul 2018 03:21:01 -0400 Content-Disposition: inline In-Reply-To: <153033282719.8297.790755582693609184.stgit@anamhost.jf.intel.com> Sender: netdev-owner@vger.kernel.org List-ID: Hello Amritha, I see a following warning on 4.18.0-rc3-next-20180703. It looks like a problem is in this series. [ 1.084722] ============================================ [ 1.084797] WARNING: possible recursive locking detected [ 1.084872] 4.18.0-rc3-next-20180703+ #1 Not tainted [ 1.084949] -------------------------------------------- [ 1.085024] swapper/0/1 is trying to acquire lock: [ 1.085100] 00000000cf973d46 (cpu_hotplug_lock.rw_sem){++++}, at: static_key_slow_inc+0xe/0x20 [ 1.085189] [ 1.085189] but task is already holding lock: [ 1.085271] 00000000cf973d46 (cpu_hotplug_lock.rw_sem){++++}, at: init_vqs+0x513/0x5a0 [ 1.085357] [ 1.085357] other info that might help us debug this: [ 1.085450] Possible unsafe locking scenario: [ 1.085450] [ 1.085531] CPU0 [ 1.085605] ---- [ 1.085679] lock(cpu_hotplug_lock.rw_sem); [ 1.085753] lock(cpu_hotplug_lock.rw_sem); [ 1.085828] [ 1.085828] *** DEADLOCK *** [ 1.085828] [ 1.085916] May be due to missing lock nesting notation [ 1.085916] [ 1.085998] 3 locks held by swapper/0/1: [ 1.086074] #0: 00000000244bc7da (&dev->mutex){....}, at: __driver_attach+0x5a/0x110 [ 1.086164] #1: 00000000cf973d46 (cpu_hotplug_lock.rw_sem){++++}, at: init_vqs+0x513/0x5a0 [ 1.086248] #2: 000000005cd8463f (xps_map_mutex){+.+.}, at: __netif_set_xps_queue+0x8d/0xc60 [ 1.086336] [ 1.086336] stack backtrace: [ 1.086419] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.18.0-rc3-next-20180703+ #1 [ 1.086504] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 1.086587] Call Trace: [ 1.086667] dump_stack+0x85/0xcb [ 1.086744] __lock_acquire+0x68a/0x1330 [ 1.086821] ? lock_acquire+0x9f/0x200 [ 1.086900] ? find_held_lock+0x2d/0x90 [ 1.086976] ? lock_acquire+0x9f/0x200 [ 1.087051] lock_acquire+0x9f/0x200 [ 1.087126] ? static_key_slow_inc+0xe/0x20 [ 1.087205] cpus_read_lock+0x3e/0x80 [ 1.087280] ? static_key_slow_inc+0xe/0x20 [ 1.087355] static_key_slow_inc+0xe/0x20 [ 1.087435] __netif_set_xps_queue+0x216/0xc60 [ 1.087512] virtnet_set_affinity+0xf0/0x130 [ 1.087589] init_vqs+0x51b/0x5a0 [ 1.087665] virtnet_probe+0x39f/0x870 [ 1.087742] virtio_dev_probe+0x170/0x220 [ 1.087819] driver_probe_device+0x30b/0x480 [ 1.087897] ? set_debug_rodata+0x11/0x11 [ 1.087972] __driver_attach+0xe0/0x110 [ 1.088064] ? driver_probe_device+0x480/0x480 [ 1.088141] bus_for_each_dev+0x79/0xc0 [ 1.088221] bus_add_driver+0x164/0x260 [ 1.088302] ? veth_init+0x11/0x11 [ 1.088379] driver_register+0x5b/0xe0 [ 1.088402] ? veth_init+0x11/0x11 [ 1.088402] virtio_net_driver_init+0x6d/0x90 [ 1.088402] do_one_initcall+0x5d/0x34c [ 1.088402] ? set_debug_rodata+0x11/0x11 [ 1.088402] ? rcu_read_lock_sched_held+0x6b/0x80 [ 1.088402] kernel_init_freeable+0x1ea/0x27b [ 1.088402] ? rest_init+0xd0/0xd0 [ 1.088402] kernel_init+0xa/0x110 [ 1.088402] ret_from_fork+0x3a/0x50 [ 1.094190] i8042: PNP: PS/2 Controller [PNP0303:KBD,PNP0f13:MOU] at 0x60,0x64 irq 1,12 https://travis-ci.org/avagin/linux/jobs/399867744 On Fri, Jun 29, 2018 at 09:27:07PM -0700, Amritha Nambiar wrote: > Extend transmit queue sysfs attribute to configure Rx queue(s) map > per Tx queue. By default no receive queues are configured for the > Tx queue. > > - /sys/class/net/eth0/queues/tx-*/xps_rxqs > > Signed-off-by: Amritha Nambiar > --- > net/core/net-sysfs.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 83 insertions(+) > > diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c > index b39987c..f25ac5f 100644 > --- a/net/core/net-sysfs.c > +++ b/net/core/net-sysfs.c > @@ -1283,6 +1283,88 @@ static ssize_t xps_cpus_store(struct netdev_queue *queue, > > static struct netdev_queue_attribute xps_cpus_attribute __ro_after_init > = __ATTR_RW(xps_cpus); > + > +static ssize_t xps_rxqs_show(struct netdev_queue *queue, char *buf) > +{ > + struct net_device *dev = queue->dev; > + struct xps_dev_maps *dev_maps; > + unsigned long *mask, index; > + int j, len, num_tc = 1, tc = 0; > + > + index = get_netdev_queue_index(queue); > + > + if (dev->num_tc) { > + num_tc = dev->num_tc; > + tc = netdev_txq_to_tc(dev, index); > + if (tc < 0) > + return -EINVAL; > + } > + mask = kcalloc(BITS_TO_LONGS(dev->num_rx_queues), sizeof(long), > + GFP_KERNEL); > + if (!mask) > + return -ENOMEM; > + > + rcu_read_lock(); > + dev_maps = rcu_dereference(dev->xps_rxqs_map); > + if (!dev_maps) > + goto out_no_maps; > + > + for (j = -1; j = netif_attrmask_next(j, NULL, dev->num_rx_queues), > + j < dev->num_rx_queues;) { > + int i, tci = j * num_tc + tc; > + struct xps_map *map; > + > + map = rcu_dereference(dev_maps->attr_map[tci]); > + if (!map) > + continue; > + > + for (i = map->len; i--;) { > + if (map->queues[i] == index) { > + set_bit(j, mask); > + break; > + } > + } > + } > +out_no_maps: > + rcu_read_unlock(); > + > + len = bitmap_print_to_pagebuf(false, buf, mask, dev->num_rx_queues); > + kfree(mask); > + > + return len < PAGE_SIZE ? len : -EINVAL; > +} > + > +static ssize_t xps_rxqs_store(struct netdev_queue *queue, const char *buf, > + size_t len) > +{ > + struct net_device *dev = queue->dev; > + struct net *net = dev_net(dev); > + unsigned long *mask, index; > + int err; > + > + if (!ns_capable(net->user_ns, CAP_NET_ADMIN)) > + return -EPERM; > + > + mask = kcalloc(BITS_TO_LONGS(dev->num_rx_queues), sizeof(long), > + GFP_KERNEL); > + if (!mask) > + return -ENOMEM; > + > + index = get_netdev_queue_index(queue); > + > + err = bitmap_parse(buf, len, mask, dev->num_rx_queues); > + if (err) { > + kfree(mask); > + return err; > + } > + > + err = __netif_set_xps_queue(dev, mask, index, true); > + kfree(mask); > + return err ? : len; > +} > + > +static struct netdev_queue_attribute xps_rxqs_attribute __ro_after_init > + = __ATTR_RW(xps_rxqs); > #endif /* CONFIG_XPS */ > > static struct attribute *netdev_queue_default_attrs[] __ro_after_init = { > @@ -1290,6 +1372,7 @@ static struct attribute *netdev_queue_default_attrs[] __ro_after_init = { > &queue_traffic_class.attr, > #ifdef CONFIG_XPS > &xps_cpus_attribute.attr, > + &xps_rxqs_attribute.attr, > &queue_tx_maxrate.attr, > #endif > NULL