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AJvYcCU1x70CHA4+tkeM1rEsyXOKzYGGFw9EpkNErsVyjr4CGNwthqZegoDX+V9DM1IGf6OfWp6aJoHCywuIlt3a3EXKzJiVVN/JdahGGUn+v0A= X-Gm-Message-State: AOJu0Yy0O2Xvralqama1+LLRzORTgeDM8iLvjqLxTHnwxozje1fKgDoh iVmABsMSOYpqsJWxg3uY4YxkCA4eL7pA44dYXEfh2FsNQvlOf3fUNt7QGCWI46U= X-Google-Smtp-Source: AGHT+IFrAvXysVgyqP+hS0kfQK7uLO5VMJ6VTPDxeoxQ2hpnNSYdogdPtpQCAktagXpfItZVMX4JdA== X-Received: by 2002:a05:6000:c84:b0:36b:c65d:f669 with SMTP id ffacd0b85a97d-3716cd23d21mr649724f8f.49.1723481243572; Mon, 12 Aug 2024 09:47:23 -0700 (PDT) Received: from localhost ([193.47.165.251]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-429c775fc9csm106931135e9.47.2024.08.12.09.47.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Aug 2024 09:47:22 -0700 (PDT) Date: Mon, 12 Aug 2024 18:47:19 +0200 From: Jiri Pirko To: Marek Szyprowski Cc: netdev@vger.kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, mst@redhat.com, jasowang@redhat.com, xuanzhuo@linux.alibaba.com, virtualization@lists.linux.dev, ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com, dave.taht@gmail.com, kerneljasonxing@gmail.com, hengqi@linux.alibaba.com Subject: Re: [PATCH net-next v3] virtio_net: add support for Byte Queue Limits Message-ID: References: <20240618144456.1688998-1-jiri@resnulli.us> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Mon, Aug 12, 2024 at 04:57:24PM CEST, m.szyprowski@samsung.com wrote: >Hi, > >On 18.06.2024 16:44, Jiri Pirko wrote: >> From: Jiri Pirko >> >> Add support for Byte Queue Limits (BQL). >> >> Tested on qemu emulated virtio_net device with 1, 2 and 4 queues. >> Tested with fq_codel and pfifo_fast. Super netperf with 50 threads is >> running in background. Netperf TCP_RR results: >> >> NOBQL FQC 1q: 159.56 159.33 158.50 154.31 agv: 157.925 >> NOBQL FQC 2q: 184.64 184.96 174.73 174.15 agv: 179.62 >> NOBQL FQC 4q: 994.46 441.96 416.50 499.56 agv: 588.12 >> NOBQL PFF 1q: 148.68 148.92 145.95 149.48 agv: 148.2575 >> NOBQL PFF 2q: 171.86 171.20 170.42 169.42 agv: 170.725 >> NOBQL PFF 4q: 1505.23 1137.23 2488.70 3507.99 agv: 2159.7875 >> BQL FQC 1q: 1332.80 1297.97 1351.41 1147.57 agv: 1282.4375 >> BQL FQC 2q: 768.30 817.72 864.43 974.40 agv: 856.2125 >> BQL FQC 4q: 945.66 942.68 878.51 822.82 agv: 897.4175 >> BQL PFF 1q: 149.69 151.49 149.40 147.47 agv: 149.5125 >> BQL PFF 2q: 2059.32 798.74 1844.12 381.80 agv: 1270.995 >> BQL PFF 4q: 1871.98 4420.02 4916.59 13268.16 agv: 6119.1875 >> >> Signed-off-by: Jiri Pirko >> --- >> v2->v3: >> - fixed the switch from/to orphan mode while skbs are yet to be >> completed by using the second least significant bit in virtqueue >> token pointer to indicate skb is orphan. Don't account orphan >> skbs in completion. >> - reorganized parallel skb/xdp free stats accounting to napi/others. >> - fixed kick condition check in orphan mode >> v1->v2: >> - moved netdev_tx_completed_queue() call into __free_old_xmit(), >> propagate use_napi flag to __free_old_xmit() and only call >> netdev_tx_completed_queue() in case it is true >> - added forgotten call to netdev_tx_reset_queue() >> - fixed stats for xdp packets >> - fixed bql accounting when __free_old_xmit() is called from xdp path >> - handle the !use_napi case in start_xmit() kick section >> --- >> drivers/net/virtio_net.c | 81 ++++++++++++++++++++++++++++------------ >> 1 file changed, 57 insertions(+), 24 deletions(-) > >I've recently found an issue with virtio-net driver and system >suspend/resume. Bisecting pointed to the c8bd1f7f3e61 ("virtio_net: add >support for Byte Queue Limits") commit and this patch. Once it got >merged to linux-next and then Linus trees, the driver occasionally >crashes with the following log (captured on QEMU's ARM 32bit 'virt' >machine): > >root@target:~# time rtcwake -s10 -mmem >rtcwake: wakeup from "mem" using /dev/rtc0 at Sat Aug 10 12:40:26 2024 >PM: suspend entry (s2idle) >Filesystems sync: 0.000 seconds >Freezing user space processes >Freezing user space processes completed (elapsed 0.006 seconds) >OOM killer disabled. >Freezing remaining freezable tasks >Freezing remaining freezable tasks completed (elapsed 0.001 seconds) >------------[ cut here ]------------ >kernel BUG at lib/dynamic_queue_limits.c:99! >Internal error: Oops - BUG: 0 [#1] SMP ARM >Modules linked in: bluetooth ecdh_generic ecc libaes >CPU: 1 PID: 1282 Comm: rtcwake Not tainted >6.10.0-rc3-00732-gc8bd1f7f3e61 #15240 >Hardware name: Generic DT based system >PC is at dql_completed+0x270/0x2cc >LR is at __free_old_xmit+0x120/0x198 >pc : []    lr : []    psr: 80000013 >... >Flags: Nzcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none >Control: 10c5387d  Table: 43a4406a  DAC: 00000051 >... >Process rtcwake (pid: 1282, stack limit = 0xfbc21278) >Stack: (0xe0805e80 to 0xe0806000) >... >Call trace: >  dql_completed from __free_old_xmit+0x120/0x198 >  __free_old_xmit from free_old_xmit+0x44/0xe4 >  free_old_xmit from virtnet_poll_tx+0x88/0x1b4 >  virtnet_poll_tx from __napi_poll+0x2c/0x1d4 >  __napi_poll from net_rx_action+0x140/0x2b4 >  net_rx_action from handle_softirqs+0x11c/0x350 >  handle_softirqs from call_with_stack+0x18/0x20 >  call_with_stack from do_softirq+0x48/0x50 >  do_softirq from __local_bh_enable_ip+0xa0/0xa4 >  __local_bh_enable_ip from virtnet_open+0xd4/0x21c >  virtnet_open from virtnet_restore+0x94/0x120 >  virtnet_restore from virtio_device_restore+0x110/0x1f4 >  virtio_device_restore from dpm_run_callback+0x3c/0x100 >  dpm_run_callback from device_resume+0x12c/0x2a8 >  device_resume from dpm_resume+0x12c/0x1e0 >  dpm_resume from dpm_resume_end+0xc/0x18 >  dpm_resume_end from suspend_devices_and_enter+0x1f0/0x72c >  suspend_devices_and_enter from pm_suspend+0x270/0x2a0 >  pm_suspend from state_store+0x68/0xc8 >  state_store from kernfs_fop_write_iter+0x10c/0x1cc >  kernfs_fop_write_iter from vfs_write+0x2b0/0x3dc >  vfs_write from ksys_write+0x5c/0xd4 >  ksys_write from ret_fast_syscall+0x0/0x54 >Exception stack(0xe8bf1fa8 to 0xe8bf1ff0) >... >---[ end trace 0000000000000000 ]--- >Kernel panic - not syncing: Fatal exception in interrupt >---[ end Kernel panic - not syncing: Fatal exception in interrupt ]--- > >I have fully reproducible setup for this issue. Reverting it together >with f8321fa75102 ("virtio_net: Fix napi_skb_cache_put warning") (due to >some code dependencies) fixes this issue on top of Linux v6.11-rc1 and >recent linux-next releases. Let me know if I can help debugging this >issue further and help fixing. Will fix this tomorrow. In the meantime, could you provide full reproduce steps? Thanks! > > > ... > >Best regards >-- >Marek Szyprowski, PhD >Samsung R&D Institute Poland >