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[75.218.246.15]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-13d130f55c6sm72975488c88.15.2026.07.26.08.42.07 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 26 Jul 2026 08:42:07 -0700 (PDT) Message-ID: <88f7d41f-43e2-4dd3-9479-8d45f2da668f@oss.qualcomm.com> Date: Sun, 26 Jul 2026 08:42:05 -0700 Precedence: bulk X-Mailing-List: linux-wireless@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH ath-next 3/8] wifi: ath12k: add TCL ring TX buffer allocation failure counter To: Pardeep Kaur , ath12k@lists.infradead.org Cc: linux-wireless@vger.kernel.org, Hariharan Ramanathan References: <20260723125448.922361-1-pardeep.kaur@oss.qualcomm.com> <20260723125448.922361-4-pardeep.kaur@oss.qualcomm.com> From: Jeff Johnson Content-Language: en-US In-Reply-To: <20260723125448.922361-4-pardeep.kaur@oss.qualcomm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Proofpoint-GUID: 5sQoJIqTVvR4Wc32A-IHKFV-I3KXCtiH X-Authority-Analysis: v=2.4 cv=HMHz0Itv c=1 sm=1 tr=0 ts=6a662ad1 cx=c_pps a=0uOsjrqzRL749jD1oC5vDA==:117 a=6VQYfvmiyQ8t40WkS/mQdw==:17 a=IkcTkHD0fZMA:10 a=RAioF0-LDSMA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=rJkE3RaqiGZ5pbrm-msn:22 a=EUspDBNiAAAA:8 a=Jcmr85nzS8LN7tR81WgA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=mQ_c8vxmzFEMiUWkPHU9:22 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzI2MDE1OSBTYWx0ZWRfX1yFumZmafybO CEDyVv9b3QOpGy84GFVcEiuGWufXl++Qziy2/uJ28jWNC5dUAPnwNBmb1jc0GOIxGcfDoqmT5Qz 6Q83HijLCQfy4AhU2U5zhQjE2lzUNNUIZ0z08j+99sX7pk88sX8W8iohCFK4oj40ohp/j4u+2// kB0XDWbzsGHCbd2l6we/ILqCFyydLm+leRmeiIWsa/6RWIo7mzr19gclBTGr+jiOpSFEO2bcID2 5pAWIe860+E+QxErwTPSBxql1lyA3X0fhLu/p3/np+F69QUqca6aGFCGJWezpyCiI8KhzAD19aI 4bFOC58c8eGHMg3V6GhztXGSosb8RH1SXPpkgVeu2Ooh7nU3SVmPT87+M8Mcc4LEWTtHDs9tlfR ZxaFLJwx/zGodtneyX49jL+yrbuZe+ngiGh2YQFIsLTqb/Jb3337VoBAKKxfVISTtn/y9NAi4W7 G1vB/b9bu5QF28ABCoQ== X-Proofpoint-Spam-Info: AW1haW4tMjYwNzI2MDE1OSBTYWx0ZWRfX7LnlrtvhZiX6 v99ZBtn+qyaPocv/dLwyGEyCO0eQnBOr++Exyh2g5wXR2L2RWtnW9yywouJG8sBMLgFv7dK1yQj yx5CHzonVj10qX0Qu0+KsRnLfeHT8X8= X-Proofpoint-ORIG-GUID: 5sQoJIqTVvR4Wc32A-IHKFV-I3KXCtiH X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-26_04,2026-07-24_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 phishscore=0 lowpriorityscore=0 impostorscore=0 suspectscore=0 bulkscore=0 clxscore=1015 priorityscore=1501 malwarescore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607260159 On 7/23/2026 5:54 AM, Pardeep Kaur wrote: > From: Hariharan Ramanathan > > When ath12k_dp_tx_assign_buffer() fails, the TX path returns -ENOMEM > silently with no per-ring visibility into how often this occurs. > Without a counter, buffer pool exhaustion on a specific TCL ring is > invisible during debugging. > > Add txbuf_na[] to ath12k_device_dp_tx_err_stats to track per-ring TX > buffer allocation failures and increment it on assign failure in the > TX path. Expose the per-ring counts in debugfs under a new 'TCL Ring > Buffer Alloc Failures' section. Is this counting the right thing? One of my review agents has the observation: The txbuf_na counter is indexed by ring_id but the exhaustion it measures is from tx_desc[pool_id] So I drilled down with another agent and got: The commit message intent is to answer "why was this frame dropped", which is valid. The practical question is whether ring_id or pool_id is more useful for diagnosis: - pool_id = skb_get_queue_mapping(skb) & 3 — a property of the traffic class/queue - ring_id = smp_processor_id() % max_tx_ring — a property of which CPU processed it If a pool is exhausted, pool_id tells you which traffic class is backpressured. ring_id tells you which CPU happened to observe it — less actionable. So the other finding is a genuine semantic improvement, not just pedantry. The fix (txbuf_na[pool_id]++) would make the stat correctly answer "which traffic class ran out of TX descriptors." So does tracking by ring_id or pool_id make the most sense? > > Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.6.r1-00402-QCAHKSWPL_SILICONZ-1 > > Signed-off-by: Hariharan Ramanathan > Co-developed-by: Pardeep Kaur > Signed-off-by: Pardeep Kaur > --- > drivers/net/wireless/ath/ath12k/debugfs.c | 5 +++++ > drivers/net/wireless/ath/ath12k/dp.h | 2 ++ > drivers/net/wireless/ath/ath12k/wifi7/dp_tx.c | 4 +++- > 3 files changed, 10 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/wireless/ath/ath12k/debugfs.c b/drivers/net/wireless/ath/ath12k/debugfs.c > index d54995b7adb2..0f8b458200a8 100644 > --- a/drivers/net/wireless/ath/ath12k/debugfs.c > +++ b/drivers/net/wireless/ath/ath12k/debugfs.c > @@ -1117,6 +1117,11 @@ static ssize_t ath12k_debugfs_dump_device_dp_stats(struct file *file, > len += scnprintf(buf + len, size - len, "ring%d: %u\n", > i, device_stats->tx_err.desc_na[i]); > > + len += scnprintf(buf + len, size - len, "\nTCL Ring Buffer Alloc Failures:\n"); > + for (i = 0; i < DP_TCL_NUM_RING_MAX; i++) > + len += scnprintf(buf + len, size - len, "ring%d: %u\n", > + i, device_stats->tx_err.txbuf_na[i]); > + > len += scnprintf(buf + len, size - len, > "\nMisc Transmit Failures: %d\n", > atomic_read(&device_stats->tx_err.misc_fail)); > diff --git a/drivers/net/wireless/ath/ath12k/dp.h b/drivers/net/wireless/ath/ath12k/dp.h > index a94bbc337df4..ac125adde258 100644 > --- a/drivers/net/wireless/ath/ath12k/dp.h > +++ b/drivers/net/wireless/ath/ath12k/dp.h > @@ -428,6 +428,8 @@ struct ath12k_dp_arch_ops { > struct ath12k_device_dp_tx_err_stats { > /* TCL Ring Descriptor unavailable */ > u32 desc_na[DP_TCL_NUM_RING_MAX]; > + /* TCL Ring Buffers unavailable */ > + u32 txbuf_na[DP_TCL_NUM_RING_MAX]; > /* Other failures during dp_tx due to mem allocation failure > * idr unavailable etc. > */ > diff --git a/drivers/net/wireless/ath/ath12k/wifi7/dp_tx.c b/drivers/net/wireless/ath/ath12k/wifi7/dp_tx.c > index a0e409452a19..ca0e1369af21 100644 > --- a/drivers/net/wireless/ath/ath12k/wifi7/dp_tx.c > +++ b/drivers/net/wireless/ath/ath12k/wifi7/dp_tx.c > @@ -123,8 +123,10 @@ int ath12k_wifi7_dp_tx(struct ath12k_pdev_dp *dp_pdev, struct ath12k_link_vif *a > tx_ring = &dp->tx_ring[ti.ring_id]; > > tx_desc = ath12k_dp_tx_assign_buffer(dp, pool_id); > - if (!tx_desc) > + if (!tx_desc) { > + dp->device_stats.tx_err.txbuf_na[ti.ring_id]++; > return -ENOMEM; > + } > > dp_link_vif = ath12k_dp_vif_to_dp_link_vif(&ahvif->dp_vif, arvif->link_id); >