From nobody Thu Oct 2 06:14:56 2025 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B48E91BD01D; Sun, 21 Sep 2025 21:45:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.156.1 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758491105; cv=none; b=n66Nt1dNbUEUGj4+Qip/ry4usWO4gAn8jGpSrnXhey3nLmBSNs8YCddBxJP5Gf8kUVAPaOMFbvZB5znzM3yszkjyEIiBhVCTrpkqBrw116N3o81IkMLUsYjq88dCcFCRMM8p0LykvgKIn33DMRxhI6NWofrbEy6GJ+2DbnnqNUk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758491105; c=relaxed/simple; bh=bStTx+PS+bydWMK0XCCAFQcJr+IduyrBa2Bcq1EXTUE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KVuT9ZFMv9+9OD6IOjL9mowr3lXTzxMJXa8gDBTvB5i9F7UOrGEU4Sjqbj2E5TvyRgI1uOlnNH7V2I/VFFvdKJ8HOh1L/ft5khSro/euJYO9FJ+CigVYJgBtG5q6k3Y5ovpO63D6KUN6p2tKnr3RV03ZwshmknKSEZdMvsi/Meg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=NNPy8AqA; arc=none smtp.client-ip=148.163.156.1 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="NNPy8AqA" Received: from pps.filterd (m0353729.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 58LLUKe6015979; Sun, 21 Sep 2025 21:44:53 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:date:from:in-reply-to:message-id :mime-version:references:subject:to; s=pp1; bh=XSiMtslDnuPKduMMT QmJwunn7OqI9AsFDs1tIG5wrJ0=; b=NNPy8AqA98Tr4pLQOgb6xUZiV7QP8Hw2Q 7GEvmD+Oz3GcoQop5k9dh5Hut+yozzb1CXQBB8kdMAmzFDcMz3YegpohmUOAnOHa t3TRXvllXL8lL0AG4K0CV5riUmxN1798y9mVHCPO3Wmz8Tj4368YeKpwzxl0Y58j GDDn6pycgBbLxxq6DY1o0s8Av2KQqy5EZGO4txep0ZZfoNPJSKAQBkVq4N+3dUlb uO7AlN5ZRBTug+FLeEVkovf9GTpBPhvGiBET1NmlRJlttf2l2rGmLert24cxSKdr dXohQxwsGbtjkEDjo8TYjq4855EeTzOPB3RGT+cd5kQzNNhLY1oWw== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 499ky5q4qv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 21 Sep 2025 21:44:52 +0000 (GMT) Received: from m0353729.ppops.net (m0353729.ppops.net [127.0.0.1]) by pps.reinject (8.18.1.12/8.18.0.8) with ESMTP id 58LLiqt6009352; Sun, 21 Sep 2025 21:44:52 GMT Received: from ppma22.wdc07v.mail.ibm.com (5c.69.3da9.ip4.static.sl-reverse.com [169.61.105.92]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 499ky5q4qs-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 21 Sep 2025 21:44:52 +0000 (GMT) Received: from pps.filterd (ppma22.wdc07v.mail.ibm.com [127.0.0.1]) by ppma22.wdc07v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 58LHOt6T008311; Sun, 21 Sep 2025 21:44:50 GMT Received: from smtprelay06.fra02v.mail.ibm.com ([9.218.2.230]) by ppma22.wdc07v.mail.ibm.com (PPS) with ESMTPS id 49a6yxkaux-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 21 Sep 2025 21:44:50 +0000 Received: from smtpav05.fra02v.mail.ibm.com (smtpav05.fra02v.mail.ibm.com [10.20.54.104]) by smtprelay06.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 58LLikv228705188 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 21 Sep 2025 21:44:46 GMT Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B1A4B20043; Sun, 21 Sep 2025 21:44:46 +0000 (GMT) Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7BE0E20040; Sun, 21 Sep 2025 21:44:46 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by smtpav05.fra02v.mail.ibm.com (Postfix) with ESMTP; Sun, 21 Sep 2025 21:44:46 +0000 (GMT) From: Halil Pasic To: Jakub Kicinski , Paolo Abeni , Simon Horman , "D. Wythe" , Dust Li , Sidraya Jayagond , Wenjia Zhang , Mahanta Jambigi , Tony Lu , Wen Gu , netdev@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, linux-s390@vger.kernel.org Cc: Halil Pasic Subject: [PATCH net-next v3 1/2] net/smc: make wr buffer count configurable Date: Sun, 21 Sep 2025 23:44:39 +0200 Message-ID: <20250921214440.325325-2-pasic@linux.ibm.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250921214440.325325-1-pasic@linux.ibm.com> References: <20250921214440.325325-1-pasic@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: h_H9pruIBawp2CKIwbP0k4HQ1WU6AODo X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwOTIwMDAyMCBTYWx0ZWRfX/3OypmLm5KMw wS1PlywVBjoM26MMYOBwy59zUDwktFFLyBr9hpGCpbBf8byX7L5zTBFntbmsu+ZKjDbu9P9oOvv KhvuWYmh2kt/CK7aRYF8M8U555mvDYzQ0x+cRxBkjqX+DZKITNu/4v0DDye6Zlv9yu+WcRb5Xsj qNkkd+RtcXL8rbNlveXojdd4LYxWJslD8alnR/nNn2sWJMDcLh4YDG2df7L1S6TGJegpGrGdl0t Aqg0FHZxvTZ7p5s35lpfFLmy8WtM/9jvqjqKdulGQ+iFyNQJlTzyXk2dWG+E7M07eYLPlTaSSwD UVlta4hGiDp8s/JhcFCRotVEzB4Qv/0VSyj/8s9EoOmO0EZVILSxpoQ7F5VJPLMAWW9PSTObNz2 ep4csnmC X-Authority-Analysis: v=2.4 cv=XYGJzJ55 c=1 sm=1 tr=0 ts=68d071d4 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=yJojWOMRYYMA:10 a=VnNF1IyMAAAA:8 a=a6OFRn_g8X_OcWKUc2YA:9 X-Proofpoint-GUID: n-L3avVN_tEcZoF216J6RPBQK6iuoO_K X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1117,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-09-21_08,2025-09-19_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 phishscore=0 clxscore=1015 adultscore=0 malwarescore=0 suspectscore=0 impostorscore=0 priorityscore=1501 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2507300000 definitions=main-2509200020 Content-Type: text/plain; charset="utf-8" Think SMC_WR_BUF_CNT_SEND :=3D SMC_WR_BUF_CNT used in send context and SMC_WR_BUF_CNT_RECV :=3D 3 * SMC_WR_BUF_CNT used in recv context. Those get replaced with lgr->max_send_wr and lgr->max_recv_wr respective. While at it let us also remove a confusing comment that is either not about the context in which it resides (describing qp_attr.cap.max_send_wr and qp_attr.cap.max_recv_wr) or not applicable any more when these values become configurable. Signed-off-by: Halil Pasic Reviewed-by: Sidraya Jayagond --- Documentation/networking/smc-sysctl.rst | 36 +++++++++++++++++++++++++ include/net/netns/smc.h | 2 ++ net/smc/smc_core.h | 6 +++++ net/smc/smc_ib.c | 7 ++--- net/smc/smc_llc.c | 2 ++ net/smc/smc_sysctl.c | 22 +++++++++++++++ net/smc/smc_sysctl.h | 2 ++ net/smc/smc_wr.c | 32 +++++++++++----------- net/smc/smc_wr.h | 2 -- 9 files changed, 89 insertions(+), 22 deletions(-) diff --git a/Documentation/networking/smc-sysctl.rst b/Documentation/networ= king/smc-sysctl.rst index a874d007f2db..c94d750c7c84 100644 --- a/Documentation/networking/smc-sysctl.rst +++ b/Documentation/networking/smc-sysctl.rst @@ -71,3 +71,39 @@ smcr_max_conns_per_lgr - INTEGER acceptable value ranges from 16 to 255. Only for SMC-R v2.1 and later. =20 Default: 255 + +smcr_max_send_wr - INTEGER + So called work request buffers are SMCR link (and RDMA queue pair) level + resources necessary for performing RDMA operations. Since up to 255 + connections can share a link group and thus also a link and the number + of the work request buffers is decided when the link is allocated, + depending on the workload it can a bottleneck in a sense that threads + have to wait for work request buffers to become available. Before the + introduction of this control the maximal number of work request buffers + available on the send path used to be hard coded to 16. With this control + it becomes configurable. The acceptable range is between 2 and 2048. + + Please be aware that all the buffers need to be allocated as a physically + continuous array in which each element is a single buffer and has the size + of SMC_WR_BUF_SIZE (48) bytes. If the allocation fails we give up much + like before having this control. + + Default: 16 + +smcr_max_recv_wr - INTEGER + So called work request buffers are SMCR link (and RDMA queue pair) level + resources necessary for performing RDMA operations. Since up to 255 + connections can share a link group and thus also a link and the number + of the work request buffers is decided when the link is allocated, + depending on the workload it can a bottleneck in a sense that threads + have to wait for work request buffers to become available. Before the + introduction of this control the maximal number of work request buffers + available on the receive path used to be hard coded to 16. With this cont= rol + it becomes configurable. The acceptable range is between 2 and 2048. + + Please be aware that all the buffers need to be allocated as a physically + continuous array in which each element is a single buffer and has the size + of SMC_WR_BUF_SIZE (48) bytes. If the allocation fails we give up much + like before having this control. + + Default: 48 diff --git a/include/net/netns/smc.h b/include/net/netns/smc.h index fc752a50f91b..6ceb12baec24 100644 --- a/include/net/netns/smc.h +++ b/include/net/netns/smc.h @@ -24,5 +24,7 @@ struct netns_smc { int sysctl_rmem; int sysctl_max_links_per_lgr; int sysctl_max_conns_per_lgr; + unsigned int sysctl_smcr_max_send_wr; + unsigned int sysctl_smcr_max_recv_wr; }; #endif diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h index 48a1b1dcb576..ab2d15929cb2 100644 --- a/net/smc/smc_core.h +++ b/net/smc/smc_core.h @@ -33,6 +33,8 @@ * distributions may modify it to a value between * 16-255 as needed. */ +#define SMCR_MAX_SEND_WR_DEF 16 /* Default number of work requests per sen= d queue */ +#define SMCR_MAX_RECV_WR_DEF 48 /* Default number of work requests per rec= v queue */ =20 struct smc_lgr_list { /* list of link group definition */ struct list_head list; @@ -361,6 +363,10 @@ struct smc_link_group { /* max conn can be assigned to lgr */ u8 max_links; /* max links can be added in lgr */ + u16 max_send_wr; + /* number of WR buffers on send */ + u16 max_recv_wr; + /* number of WR buffers on recv */ }; struct { /* SMC-D */ struct smcd_gid peer_gid; diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c index 0052f02756eb..e8d35c22c525 100644 --- a/net/smc/smc_ib.c +++ b/net/smc/smc_ib.c @@ -669,11 +669,6 @@ int smc_ib_create_queue_pair(struct smc_link *lnk) .recv_cq =3D lnk->smcibdev->roce_cq_recv, .srq =3D NULL, .cap =3D { - /* include unsolicited rdma_writes as well, - * there are max. 2 RDMA_WRITE per 1 WR_SEND - */ - .max_send_wr =3D SMC_WR_BUF_CNT * 3, - .max_recv_wr =3D SMC_WR_BUF_CNT * 3, .max_send_sge =3D SMC_IB_MAX_SEND_SGE, .max_recv_sge =3D lnk->wr_rx_sge_cnt, .max_inline_data =3D 0, @@ -683,6 +678,8 @@ int smc_ib_create_queue_pair(struct smc_link *lnk) }; int rc; =20 + qp_attr.cap.max_send_wr =3D 3 * lnk->lgr->max_send_wr; + qp_attr.cap.max_recv_wr =3D lnk->lgr->max_recv_wr; lnk->roce_qp =3D ib_create_qp(lnk->roce_pd, &qp_attr); rc =3D PTR_ERR_OR_ZERO(lnk->roce_qp); if (IS_ERR(lnk->roce_qp)) diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c index f865c58c3aa7..f5d5eb617526 100644 --- a/net/smc/smc_llc.c +++ b/net/smc/smc_llc.c @@ -2157,6 +2157,8 @@ void smc_llc_lgr_init(struct smc_link_group *lgr, str= uct smc_sock *smc) init_waitqueue_head(&lgr->llc_msg_waiter); init_rwsem(&lgr->llc_conf_mutex); lgr->llc_testlink_time =3D READ_ONCE(net->smc.sysctl_smcr_testlink_time); + lgr->max_send_wr =3D (u16)(READ_ONCE(net->smc.sysctl_smcr_max_send_wr)); + lgr->max_recv_wr =3D (u16)(READ_ONCE(net->smc.sysctl_smcr_max_recv_wr)); } =20 /* called after lgr was removed from lgr_list */ diff --git a/net/smc/smc_sysctl.c b/net/smc/smc_sysctl.c index 2fab6456f765..7b2471904d04 100644 --- a/net/smc/smc_sysctl.c +++ b/net/smc/smc_sysctl.c @@ -29,6 +29,8 @@ static int links_per_lgr_min =3D SMC_LINKS_ADD_LNK_MIN; static int links_per_lgr_max =3D SMC_LINKS_ADD_LNK_MAX; static int conns_per_lgr_min =3D SMC_CONN_PER_LGR_MIN; static int conns_per_lgr_max =3D SMC_CONN_PER_LGR_MAX; +static unsigned int smcr_max_wr_min =3D 2; +static unsigned int smcr_max_wr_max =3D 2048; =20 static struct ctl_table smc_table[] =3D { { @@ -99,6 +101,24 @@ static struct ctl_table smc_table[] =3D { .extra1 =3D SYSCTL_ZERO, .extra2 =3D SYSCTL_ONE, }, + { + .procname =3D "smcr_max_send_wr", + .data =3D &init_net.smc.sysctl_smcr_max_send_wr, + .maxlen =3D sizeof(int), + .mode =3D 0644, + .proc_handler =3D proc_dointvec_minmax, + .extra1 =3D &smcr_max_wr_min, + .extra2 =3D &smcr_max_wr_max, + }, + { + .procname =3D "smcr_max_recv_wr", + .data =3D &init_net.smc.sysctl_smcr_max_recv_wr, + .maxlen =3D sizeof(int), + .mode =3D 0644, + .proc_handler =3D proc_dointvec_minmax, + .extra1 =3D &smcr_max_wr_min, + .extra2 =3D &smcr_max_wr_max, + }, }; =20 int __net_init smc_sysctl_net_init(struct net *net) @@ -130,6 +150,8 @@ int __net_init smc_sysctl_net_init(struct net *net) WRITE_ONCE(net->smc.sysctl_rmem, net_smc_rmem_init); net->smc.sysctl_max_links_per_lgr =3D SMC_LINKS_PER_LGR_MAX_PREFER; net->smc.sysctl_max_conns_per_lgr =3D SMC_CONN_PER_LGR_PREFER; + net->smc.sysctl_smcr_max_send_wr =3D SMCR_MAX_SEND_WR_DEF; + net->smc.sysctl_smcr_max_recv_wr =3D SMCR_MAX_RECV_WR_DEF; /* disable handshake limitation by default */ net->smc.limit_smc_hs =3D 0; =20 diff --git a/net/smc/smc_sysctl.h b/net/smc/smc_sysctl.h index eb2465ae1e15..8538915af7af 100644 --- a/net/smc/smc_sysctl.h +++ b/net/smc/smc_sysctl.h @@ -25,6 +25,8 @@ static inline int smc_sysctl_net_init(struct net *net) net->smc.sysctl_autocorking_size =3D SMC_AUTOCORKING_DEFAULT_SIZE; net->smc.sysctl_max_links_per_lgr =3D SMC_LINKS_PER_LGR_MAX_PREFER; net->smc.sysctl_max_conns_per_lgr =3D SMC_CONN_PER_LGR_PREFER; + net->smc.sysctl_smcr_max_send_wr =3D SMCR_MAX_SEND_WR_DEF; + net->smc.sysctl_smcr_max_recv_wr =3D SMCR_MAX_RECV_WR_DEF; return 0; } =20 diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c index b04a21b8c511..f5b2772414fd 100644 --- a/net/smc/smc_wr.c +++ b/net/smc/smc_wr.c @@ -34,6 +34,7 @@ #define SMC_WR_MAX_POLL_CQE 10 /* max. # of compl. queue elements in 1 pol= l */ =20 #define SMC_WR_RX_HASH_BITS 4 + static DEFINE_HASHTABLE(smc_wr_rx_hash, SMC_WR_RX_HASH_BITS); static DEFINE_SPINLOCK(smc_wr_rx_hash_lock); =20 @@ -547,9 +548,9 @@ void smc_wr_remember_qp_attr(struct smc_link *lnk) IB_QP_DEST_QPN, &init_attr); =20 - lnk->wr_tx_cnt =3D min_t(size_t, SMC_WR_BUF_CNT, + lnk->wr_tx_cnt =3D min_t(size_t, lnk->lgr->max_send_wr, lnk->qp_attr.cap.max_send_wr); - lnk->wr_rx_cnt =3D min_t(size_t, SMC_WR_BUF_CNT * 3, + lnk->wr_rx_cnt =3D min_t(size_t, lnk->lgr->max_recv_wr, lnk->qp_attr.cap.max_recv_wr); } =20 @@ -741,50 +742,51 @@ int smc_wr_alloc_lgr_mem(struct smc_link_group *lgr) int smc_wr_alloc_link_mem(struct smc_link *link) { /* allocate link related memory */ - link->wr_tx_bufs =3D kcalloc(SMC_WR_BUF_CNT, SMC_WR_BUF_SIZE, GFP_KERNEL); + link->wr_tx_bufs =3D kcalloc(link->lgr->max_send_wr, + SMC_WR_BUF_SIZE, GFP_KERNEL); if (!link->wr_tx_bufs) goto no_mem; - link->wr_rx_bufs =3D kcalloc(SMC_WR_BUF_CNT * 3, link->wr_rx_buflen, + link->wr_rx_bufs =3D kcalloc(link->lgr->max_recv_wr, link->wr_rx_buflen, GFP_KERNEL); if (!link->wr_rx_bufs) goto no_mem_wr_tx_bufs; - link->wr_tx_ibs =3D kcalloc(SMC_WR_BUF_CNT, sizeof(link->wr_tx_ibs[0]), - GFP_KERNEL); + link->wr_tx_ibs =3D kcalloc(link->lgr->max_send_wr, + sizeof(link->wr_tx_ibs[0]), GFP_KERNEL); if (!link->wr_tx_ibs) goto no_mem_wr_rx_bufs; - link->wr_rx_ibs =3D kcalloc(SMC_WR_BUF_CNT * 3, + link->wr_rx_ibs =3D kcalloc(link->lgr->max_recv_wr, sizeof(link->wr_rx_ibs[0]), GFP_KERNEL); if (!link->wr_rx_ibs) goto no_mem_wr_tx_ibs; - link->wr_tx_rdmas =3D kcalloc(SMC_WR_BUF_CNT, + link->wr_tx_rdmas =3D kcalloc(link->lgr->max_send_wr, sizeof(link->wr_tx_rdmas[0]), GFP_KERNEL); if (!link->wr_tx_rdmas) goto no_mem_wr_rx_ibs; - link->wr_tx_rdma_sges =3D kcalloc(SMC_WR_BUF_CNT, + link->wr_tx_rdma_sges =3D kcalloc(link->lgr->max_send_wr, sizeof(link->wr_tx_rdma_sges[0]), GFP_KERNEL); if (!link->wr_tx_rdma_sges) goto no_mem_wr_tx_rdmas; - link->wr_tx_sges =3D kcalloc(SMC_WR_BUF_CNT, sizeof(link->wr_tx_sges[0]), + link->wr_tx_sges =3D kcalloc(link->lgr->max_send_wr, sizeof(link->wr_tx_s= ges[0]), GFP_KERNEL); if (!link->wr_tx_sges) goto no_mem_wr_tx_rdma_sges; - link->wr_rx_sges =3D kcalloc(SMC_WR_BUF_CNT * 3, + link->wr_rx_sges =3D kcalloc(link->lgr->max_recv_wr, sizeof(link->wr_rx_sges[0]) * link->wr_rx_sge_cnt, GFP_KERNEL); if (!link->wr_rx_sges) goto no_mem_wr_tx_sges; - link->wr_tx_mask =3D bitmap_zalloc(SMC_WR_BUF_CNT, GFP_KERNEL); + link->wr_tx_mask =3D bitmap_zalloc(link->lgr->max_send_wr, GFP_KERNEL); if (!link->wr_tx_mask) goto no_mem_wr_rx_sges; - link->wr_tx_pends =3D kcalloc(SMC_WR_BUF_CNT, + link->wr_tx_pends =3D kcalloc(link->lgr->max_send_wr, sizeof(link->wr_tx_pends[0]), GFP_KERNEL); if (!link->wr_tx_pends) goto no_mem_wr_tx_mask; - link->wr_tx_compl =3D kcalloc(SMC_WR_BUF_CNT, + link->wr_tx_compl =3D kcalloc(link->lgr->max_send_wr, sizeof(link->wr_tx_compl[0]), GFP_KERNEL); if (!link->wr_tx_compl) @@ -905,7 +907,7 @@ int smc_wr_create_link(struct smc_link *lnk) goto dma_unmap; } smc_wr_init_sge(lnk); - bitmap_zero(lnk->wr_tx_mask, SMC_WR_BUF_CNT); + bitmap_zero(lnk->wr_tx_mask, lnk->lgr->max_send_wr); init_waitqueue_head(&lnk->wr_tx_wait); rc =3D percpu_ref_init(&lnk->wr_tx_refs, smcr_wr_tx_refs_free, 0, GFP_KER= NEL); if (rc) diff --git a/net/smc/smc_wr.h b/net/smc/smc_wr.h index f3008dda222a..aa4533af9122 100644 --- a/net/smc/smc_wr.h +++ b/net/smc/smc_wr.h @@ -19,8 +19,6 @@ #include "smc.h" #include "smc_core.h" =20 -#define SMC_WR_BUF_CNT 16 /* # of ctrl buffers per link */ - #define SMC_WR_TX_WAIT_FREE_SLOT_TIME (10 * HZ) =20 #define SMC_WR_TX_SIZE 44 /* actual size of wr_send data (<=3DSMC_WR_BUF_S= IZE) */ --=20 2.48.1 From nobody Thu Oct 2 06:14:56 2025 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B2C0C2C3251; Sun, 21 Sep 2025 21:45:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.156.1 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758491106; cv=none; b=DNGG6qp1uUXQx+CcdhgwLqHwy2QJ9ZIOBrabsS4KJCOST5BUvGkUQiZCoIoGTfFQF8OKK0YoelJG8NvTrJBwiytNj7LjsvPlUB5G2k87+G6zO5Mk8WiymFfqWP7SgLdo7tvKNjt9vTo8qhovUdfcyecM0A5Vqo3zcyXvOP+HBYE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758491106; c=relaxed/simple; bh=CbmDTP8h53MG2g84pS1mnV8p4mkYAcrqZnbCQEF5x/I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=p1I3r3XCYv1grj8fhy72i3skc0RCgUNlR/7uNHnI7giWu/KYri5wPgWaw35HZ0jwEUd6Yp3a6F/aPpu4evJU8n2ZCgQuehIIb2f4TtzUm0w9QgAVAlVPwjjOL0y0EKXfvmTD5+nmei5AVBm5zwszzuUsO4ljFzLMyl8tCJKkcv8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=dG2xKJxu; arc=none smtp.client-ip=148.163.156.1 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="dG2xKJxu" Received: from pps.filterd (m0353729.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 58LBQeoh017068; Sun, 21 Sep 2025 21:44:53 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:date:from:in-reply-to:message-id :mime-version:references:subject:to; s=pp1; bh=rpWAmSzRr0l1DuNzP 6UkVcw3Fb5aM5LXJoByQJyVPIE=; b=dG2xKJxuSA0V0SVs8ILNAVPTWboxCLfOq p95GMYgIhYyXpgYsrRgmYyKMpTCEhPwEf3Wj6hkLLZVISft/IuWF8DJAlq0sQiEk /j0j5kOef0V6/aMglrPYaMW+DbybfFPLaamUiIrjk+p5SGY1FusItrEe8vnVIAFd iEnsyXx5LS9wN4FgM98JwMF4fAj2ZwGZv37p8r7jvCsSe49b8yAOXRnM5ejXDfK0 qttA4/fFVw+TBH08IwBQM8S3kDoNNGZbKRb83jQJ4LXZXdpDn0ic5jn2FxyGLoYQ Vm0MIaX/8HElqku/dFRTkTureioxMIxRatvf94QlJ/jA0qsSqZJ/A== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 499ky5q4qy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 21 Sep 2025 21:44:53 +0000 (GMT) Received: from m0353729.ppops.net (m0353729.ppops.net [127.0.0.1]) by pps.reinject (8.18.1.12/8.18.0.8) with ESMTP id 58LLiqt8009352; Sun, 21 Sep 2025 21:44:52 GMT Received: from ppma12.dal12v.mail.ibm.com (dc.9e.1632.ip4.static.sl-reverse.com [50.22.158.220]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 499ky5q4qt-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 21 Sep 2025 21:44:52 +0000 (GMT) Received: from pps.filterd (ppma12.dal12v.mail.ibm.com [127.0.0.1]) by ppma12.dal12v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 58LGp7OG029540; Sun, 21 Sep 2025 21:44:51 GMT Received: from smtprelay07.fra02v.mail.ibm.com ([9.218.2.229]) by ppma12.dal12v.mail.ibm.com (PPS) with ESMTPS id 49a6krkd63-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 21 Sep 2025 21:44:51 +0000 Received: from smtpav05.fra02v.mail.ibm.com (smtpav05.fra02v.mail.ibm.com [10.20.54.104]) by smtprelay07.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 58LLilrZ37355934 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 21 Sep 2025 21:44:47 GMT Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BE9502004B; Sun, 21 Sep 2025 21:44:47 +0000 (GMT) Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 89C8120043; Sun, 21 Sep 2025 21:44:47 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by smtpav05.fra02v.mail.ibm.com (Postfix) with ESMTP; Sun, 21 Sep 2025 21:44:47 +0000 (GMT) From: Halil Pasic To: Jakub Kicinski , Paolo Abeni , Simon Horman , "D. Wythe" , Dust Li , Sidraya Jayagond , Wenjia Zhang , Mahanta Jambigi , Tony Lu , Wen Gu , netdev@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, linux-s390@vger.kernel.org Cc: Halil Pasic Subject: [PATCH net-next v3 2/2] net/smc: handle -ENOMEM from smc_wr_alloc_link_mem gracefully Date: Sun, 21 Sep 2025 23:44:40 +0200 Message-ID: <20250921214440.325325-3-pasic@linux.ibm.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250921214440.325325-1-pasic@linux.ibm.com> References: <20250921214440.325325-1-pasic@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: IdjHpc584FZtdSjVPQLcTlh5PHPpa3xl X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwOTIwMDAyMCBTYWx0ZWRfXx8zdGlKAw5yH Z98VoLL65NyAaDaOdq1qGBOrOkfp4uPGAsfL8/ydOYlWjibA3gkyJIhPkQB03oYu4HtOxb33gEp H76Wh6VDArcNWhdRFDLM2D8rL9k3GwFxjc6KlBtkyreDorle25uO3SV7EGVTa/aPjgDFUNrYIBR oJt1Kg/zWXOez8nS/YC2K9FxjxVfKJaLoiWMmnu1moOyR/jG7ooo3caOmD8wNdzZnNRVgvSrRzS d6RZuEp7r2/sPXRDIrdz4uSp0qo5DI8RcrSnAK5lAxL1D8jrM0CXMNMPbeM3zxs+0yE4DFL9brt nn0ZZKUzYyQGPtzHOUoNVKGmltBHiPkCdw+ilU2lBonOYVy+IATbbrUs7O7MIkFea9fHhwaSCi1 JvCA4wBZ X-Authority-Analysis: v=2.4 cv=XYGJzJ55 c=1 sm=1 tr=0 ts=68d071d5 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=yJojWOMRYYMA:10 a=VnNF1IyMAAAA:8 a=7VMdMTDjWeNOirE0wYMA:9 X-Proofpoint-GUID: U76d1UJCnSqmq01zK53ZyBeshX9Henck X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1117,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-09-21_08,2025-09-19_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 phishscore=0 clxscore=1015 adultscore=0 malwarescore=0 suspectscore=0 impostorscore=0 priorityscore=1501 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2507300000 definitions=main-2509200020 Content-Type: text/plain; charset="utf-8" Currently if a -ENOMEM from smc_wr_alloc_link_mem() is handled by giving up and going the way of a TCP fallback. This was reasonable before the sizes of the allocations there were compile time constants and reasonably small. But now those are actually configurable. So instead of giving up, keep retrying with half of the requested size unless we dip below the old static sizes -- then give up! Signed-off-by: Halil Pasic Reviewed-by: Wenjia Zhang Reviewed-by: Mahanta Jambigi Reviewed-by: Sidraya Jayagond --- Documentation/networking/smc-sysctl.rst | 8 ++++-- net/smc/smc_core.c | 34 +++++++++++++++++-------- net/smc/smc_core.h | 2 ++ net/smc/smc_wr.c | 28 ++++++++++---------- 4 files changed, 46 insertions(+), 26 deletions(-) diff --git a/Documentation/networking/smc-sysctl.rst b/Documentation/networ= king/smc-sysctl.rst index c94d750c7c84..c8dbe7ac8bdf 100644 --- a/Documentation/networking/smc-sysctl.rst +++ b/Documentation/networking/smc-sysctl.rst @@ -85,7 +85,9 @@ smcr_max_send_wr - INTEGER =20 Please be aware that all the buffers need to be allocated as a physically continuous array in which each element is a single buffer and has the size - of SMC_WR_BUF_SIZE (48) bytes. If the allocation fails we give up much + of SMC_WR_BUF_SIZE (48) bytes. If the allocation fails, we keep retrying + with half of the buffer count until it is ether successful or (unlikely) + we dip below the old hard coded value which is 16 where we give up much like before having this control. =20 Default: 16 @@ -103,7 +105,9 @@ smcr_max_recv_wr - INTEGER =20 Please be aware that all the buffers need to be allocated as a physically continuous array in which each element is a single buffer and has the size - of SMC_WR_BUF_SIZE (48) bytes. If the allocation fails we give up much + of SMC_WR_BUF_SIZE (48) bytes. If the allocation fails, we keep retrying + with half of the buffer count until it is ether successful or (unlikely) + we dip below the old hard coded value which is 16 where we give up much like before having this control. =20 Default: 48 diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index 2a559a98541c..f8131b4dfcd6 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -810,6 +810,8 @@ int smcr_link_init(struct smc_link_group *lgr, struct s= mc_link *lnk, lnk->clearing =3D 0; lnk->path_mtu =3D lnk->smcibdev->pattr[lnk->ibport - 1].active_mtu; lnk->link_id =3D smcr_next_link_id(lgr); + lnk->max_send_wr =3D lgr->max_send_wr; + lnk->max_recv_wr =3D lgr->max_recv_wr; lnk->lgr =3D lgr; smc_lgr_hold(lgr); /* lgr_put in smcr_link_clear() */ lnk->link_idx =3D link_idx; @@ -836,27 +838,39 @@ int smcr_link_init(struct smc_link_group *lgr, struct= smc_link *lnk, rc =3D smc_llc_link_init(lnk); if (rc) goto out; - rc =3D smc_wr_alloc_link_mem(lnk); - if (rc) - goto clear_llc_lnk; rc =3D smc_ib_create_protection_domain(lnk); if (rc) - goto free_link_mem; - rc =3D smc_ib_create_queue_pair(lnk); - if (rc) - goto dealloc_pd; + goto clear_llc_lnk; + do { + rc =3D smc_ib_create_queue_pair(lnk); + if (rc) + goto dealloc_pd; + rc =3D smc_wr_alloc_link_mem(lnk); + if (!rc) + break; + else if (rc !=3D -ENOMEM) /* give up */ + goto destroy_qp; + /* retry with smaller ... */ + lnk->max_send_wr /=3D 2; + lnk->max_recv_wr /=3D 2; + /* ... unless droping below old SMC_WR_BUF_SIZE */ + if (lnk->max_send_wr < 16 || lnk->max_recv_wr < 48) + goto destroy_qp; + smc_ib_destroy_queue_pair(lnk); + } while (1); + rc =3D smc_wr_create_link(lnk); if (rc) - goto destroy_qp; + goto free_link_mem; lnk->state =3D SMC_LNK_ACTIVATING; return 0; =20 +free_link_mem: + smc_wr_free_link_mem(lnk); destroy_qp: smc_ib_destroy_queue_pair(lnk); dealloc_pd: smc_ib_dealloc_protection_domain(lnk); -free_link_mem: - smc_wr_free_link_mem(lnk); clear_llc_lnk: smc_llc_link_clear(lnk, false); out: diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h index ab2d15929cb2..b9addf633d8a 100644 --- a/net/smc/smc_core.h +++ b/net/smc/smc_core.h @@ -174,6 +174,8 @@ struct smc_link { struct completion llc_testlink_resp; /* wait for rx of testlink */ int llc_testlink_time; /* testlink interval */ atomic_t conn_cnt; /* connections on this link */ + u16 max_send_wr; + u16 max_recv_wr; }; =20 /* For now we just allow one parallel link per link group. The SMC protocol diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c index f5b2772414fd..6b14711f0c93 100644 --- a/net/smc/smc_wr.c +++ b/net/smc/smc_wr.c @@ -548,9 +548,9 @@ void smc_wr_remember_qp_attr(struct smc_link *lnk) IB_QP_DEST_QPN, &init_attr); =20 - lnk->wr_tx_cnt =3D min_t(size_t, lnk->lgr->max_send_wr, + lnk->wr_tx_cnt =3D min_t(size_t, lnk->max_send_wr, lnk->qp_attr.cap.max_send_wr); - lnk->wr_rx_cnt =3D min_t(size_t, lnk->lgr->max_recv_wr, + lnk->wr_rx_cnt =3D min_t(size_t, lnk->max_recv_wr, lnk->qp_attr.cap.max_recv_wr); } =20 @@ -742,51 +742,51 @@ int smc_wr_alloc_lgr_mem(struct smc_link_group *lgr) int smc_wr_alloc_link_mem(struct smc_link *link) { /* allocate link related memory */ - link->wr_tx_bufs =3D kcalloc(link->lgr->max_send_wr, + link->wr_tx_bufs =3D kcalloc(link->max_send_wr, SMC_WR_BUF_SIZE, GFP_KERNEL); if (!link->wr_tx_bufs) goto no_mem; - link->wr_rx_bufs =3D kcalloc(link->lgr->max_recv_wr, link->wr_rx_buflen, + link->wr_rx_bufs =3D kcalloc(link->max_recv_wr, link->wr_rx_buflen, GFP_KERNEL); if (!link->wr_rx_bufs) goto no_mem_wr_tx_bufs; - link->wr_tx_ibs =3D kcalloc(link->lgr->max_send_wr, + link->wr_tx_ibs =3D kcalloc(link->max_send_wr, sizeof(link->wr_tx_ibs[0]), GFP_KERNEL); if (!link->wr_tx_ibs) goto no_mem_wr_rx_bufs; - link->wr_rx_ibs =3D kcalloc(link->lgr->max_recv_wr, + link->wr_rx_ibs =3D kcalloc(link->max_recv_wr, sizeof(link->wr_rx_ibs[0]), GFP_KERNEL); if (!link->wr_rx_ibs) goto no_mem_wr_tx_ibs; - link->wr_tx_rdmas =3D kcalloc(link->lgr->max_send_wr, + link->wr_tx_rdmas =3D kcalloc(link->max_send_wr, sizeof(link->wr_tx_rdmas[0]), GFP_KERNEL); if (!link->wr_tx_rdmas) goto no_mem_wr_rx_ibs; - link->wr_tx_rdma_sges =3D kcalloc(link->lgr->max_send_wr, + link->wr_tx_rdma_sges =3D kcalloc(link->max_send_wr, sizeof(link->wr_tx_rdma_sges[0]), GFP_KERNEL); if (!link->wr_tx_rdma_sges) goto no_mem_wr_tx_rdmas; - link->wr_tx_sges =3D kcalloc(link->lgr->max_send_wr, sizeof(link->wr_tx_s= ges[0]), + link->wr_tx_sges =3D kcalloc(link->max_send_wr, sizeof(link->wr_tx_sges[0= ]), GFP_KERNEL); if (!link->wr_tx_sges) goto no_mem_wr_tx_rdma_sges; - link->wr_rx_sges =3D kcalloc(link->lgr->max_recv_wr, + link->wr_rx_sges =3D kcalloc(link->max_recv_wr, sizeof(link->wr_rx_sges[0]) * link->wr_rx_sge_cnt, GFP_KERNEL); if (!link->wr_rx_sges) goto no_mem_wr_tx_sges; - link->wr_tx_mask =3D bitmap_zalloc(link->lgr->max_send_wr, GFP_KERNEL); + link->wr_tx_mask =3D bitmap_zalloc(link->max_send_wr, GFP_KERNEL); if (!link->wr_tx_mask) goto no_mem_wr_rx_sges; - link->wr_tx_pends =3D kcalloc(link->lgr->max_send_wr, + link->wr_tx_pends =3D kcalloc(link->max_send_wr, sizeof(link->wr_tx_pends[0]), GFP_KERNEL); if (!link->wr_tx_pends) goto no_mem_wr_tx_mask; - link->wr_tx_compl =3D kcalloc(link->lgr->max_send_wr, + link->wr_tx_compl =3D kcalloc(link->max_send_wr, sizeof(link->wr_tx_compl[0]), GFP_KERNEL); if (!link->wr_tx_compl) @@ -907,7 +907,7 @@ int smc_wr_create_link(struct smc_link *lnk) goto dma_unmap; } smc_wr_init_sge(lnk); - bitmap_zero(lnk->wr_tx_mask, lnk->lgr->max_send_wr); + bitmap_zero(lnk->wr_tx_mask, lnk->max_send_wr); init_waitqueue_head(&lnk->wr_tx_wait); rc =3D percpu_ref_init(&lnk->wr_tx_refs, smcr_wr_tx_refs_free, 0, GFP_KER= NEL); if (rc) --=20 2.48.1