From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 4F6A82BE7DD; Tue, 21 Jul 2026 04:50:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784609437; cv=none; b=ZfygZ9QIppdTq+vSe2ePsN2sl+S7o0HzoamyW2sTcJH49aNBq2QnMEj9rp8+KWDEu8aW86O16kUYHIwON9myUPMCG79RaGYuZZ7B+WzZVdWRBhKcOSdHg0OmlOVOyWl8btRgAfJWMSg13Stag7CyVynsQbNiHpNTI+nHMceo3b4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784609437; c=relaxed/simple; bh=f44eNukRggsUOpfrKivaXG/WM00O/Km2KdALa95b5q8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=qllktUo9zvMd7m3VXyWh6KUZ6smT27rWmKi7rUMY67yKcF3ZjNvIYZmEPG8S1r9mROredefN5rcIWuQ+KELmxSEh9eo0yTCj0U0aThlV+thC5JFdP6gJ/wzH4KywoY2PFWbXQjDig1Fmz4QNvNyiy5Qt0QHq/cnpNuE/q2KxdOM= 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=Od0A7Geq; arc=none smtp.client-ip=148.163.158.5 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="Od0A7Geq" Received: from pps.filterd (m0360072.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 66KNDtfu3562185; Tue, 21 Jul 2026 04:50:18 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=pp1; bh=AaAsoz OWwpCuYCq26EovY7890xu/04NvsGRJ8k2E82c=; b=Od0A7Geq5iOaz/P0XwGLmI 4ht34cL07iSTvV4O6Ca57ocVytOsRBhWI6xrcl4Ytbag1uY/O4j9zo0qTs2Emhen MQuPmUoD7/pdJqbN1dww5LMcgbD7ImFTIT9aDX836qWi8K/HrBb+aFQKrvJSAU8T J8j1LepE4oczse/3Qjg6OQN3A6WyUR/CCJHD0VeqF2q2m/culjSAaWCi3DcLdy4Z DV75hqy/CQAaAEQtzh2B1qOghL7B51nBuJyK9JefQt4Ht0ha+MLIwD0G3HoHFTrh nfeEPc2SRnqlUslUWXmIT/Gjknyby9q25lW2NoHwq9lCGTZ2UEmusaVWjuaXbxmA == 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 4fg7ah2h31-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 21 Jul 2026 04:50:17 +0000 (GMT) Received: from pps.filterd (ppma12.dal12v.mail.ibm.com [127.0.0.1]) by ppma12.dal12v.mail.ibm.com (8.18.1.7/8.18.1.7) with ESMTP id 66L4YsEd029523; Tue, 21 Jul 2026 04:50:16 GMT Received: from smtprelay06.fra02v.mail.ibm.com ([9.218.2.230]) by ppma12.dal12v.mail.ibm.com (PPS) with ESMTPS id 4fgktq0xgc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 21 Jul 2026 04:50:16 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (smtpav02.fra02v.mail.ibm.com [10.20.54.101]) by smtprelay06.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 66L4oC7029688144 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 21 Jul 2026 04:50:12 GMT Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C1C192004E; Tue, 21 Jul 2026 04:50:12 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 88D7620043; Tue, 21 Jul 2026 04:50:04 +0000 (GMT) Received: from [9.39.17.99] (unknown [9.39.17.99]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Tue, 21 Jul 2026 04:50:04 +0000 (GMT) Message-ID: <5bf27f85-6d07-4f40-8604-8b9ac9777db9@linux.ibm.com> Date: Tue, 21 Jul 2026 10:20:03 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] net/sock: Propagate WF_SYNC only when requested To: Srikar Dronamraju , LKML , netdev@vger.kernel.org, David S Miller Cc: Ingo Molnar , Peter Zijlstra , Dietmar Eggemann , Dust Li , D Wythe , Eric Dumazet , Jakub Kicinski , Jon Maloy , Kuniyuki Iwashima , linux-sctp@vger.kernel.org, Mahanta Jambigi , Marcelo Ricardo Leitner , Paolo Abeni , Sidraya Jayagond , Simon Horman , Tony Lu , Wen Gu , Wenjia Zhang , Willem de Bruijn , Xin Long , Vincent Guittot , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak References: <20260714013940.4068189-4-srikar@linux.ibm.com> <20260714013940.4068189-6-srikar@linux.ibm.com> From: Shrikanth Hegde Content-Language: en-US In-Reply-To: <20260714013940.4068189-6-srikar@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-ORIG-GUID: _cuN3Wvogp_F8jne52Pgw_JkWJVrJa_v X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzIxMDA0NSBTYWx0ZWRfX4xYt7JMvz5z1 Bf5LIlFQspUoxRlJ6HekthQZD+gNgr316yeik9ap1kFfY434MojTPU0nQKaGFFJ1Sq2DwVCNmen 3erGPyMgPulX+Yy6a5Rnr34SGFS9Gs6CBFfLQLwVmWWLOKJ9tYOrFuhrvfICVvDIVoCglJj70ef gqEVbWeUalngklFihbsUvBWKjHpNmDlkRG43tpGX7i5VJNWri3pdn3gu/wZghPrCiAuW49zr9GB LkSDAi3sEU2qzFTj14VEyWmqma8na1Zw1XOZrCFJLZmr0jYQntBA4S/XbYykat6GKse8UBYoWLP 4m/JYwxVaDJ++nXmMk+JyAqhp74jhnXD9OkJ68ol5cKQiCo2Bcd3LNCEOBw7JrPGWVt42jJj4+o CeYLUCo8xI28xyWOGXiU96eTzO3weQVITvfbYKJfEZ3MaWRG3BTobTkRYsRu/ASCJve5Y334zhw BR4+zvd2S2+o+HPXVxg== X-Proofpoint-Spam-Info: AW1haW4tMjYwNzIxMDA0NSBTYWx0ZWRfX/dX4ql4EQfVx fmlnV1Ps2rTdKDfvNJbXVRRFpCfqVLB0tyJzFofI4POJoS3npS57+D+AhtNwIMEA6JDxsURIjcS i3aXZICDROMkvRinC4yEItKFH1StpD4= X-Proofpoint-GUID: 4AsqktYc_fNMp6ryw98x1VyCDdoLAjun X-Authority-Analysis: v=2.4 cv=SM5ykuvH c=1 sm=1 tr=0 ts=6a5efa8a cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VnNF1IyMAAAA:8 a=D7B-jMnUd-_QZL7UbJsA:9 a=QEXdDO2ut3YA:10 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=2026-07-20_06,2026-07-20_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1011 lowpriorityscore=0 bulkscore=0 suspectscore=0 adultscore=0 spamscore=0 malwarescore=0 priorityscore=1501 phishscore=0 impostorscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607210045 Hi Srikar, On 7/14/26 7:09 AM, Srikar Dronamraju wrote: > Use SOCK_SYNC_WAKEUP to select between synchronous and asynchronous wakeup > wakeup APIs. This avoids propagating WF_SYNC when no blocking waiter is > expected. All wakeup locations in networking code that currently issue > synchronous poll-style wakeups unconditionally are updated. > You can also add the performance data in the cover-letter to this patch. > Signed-off-by: Srikar Dronamraju > --- > net/core/sock.c | 31 ++++++++++++++++++++++++------- > net/sctp/socket.c | 10 ++++++++-- > net/smc/af_smc.c | 4 ++-- > net/smc/smc_rx.c | 10 ++++++++-- > net/tipc/socket.c | 22 +++++++++++++++++----- > net/unix/af_unix.c | 26 ++++++++++++++++++-------- > 6 files changed, 77 insertions(+), 26 deletions(-) > > diff --git a/net/core/sock.c b/net/core/sock.c > index 8a59bfaa8096..a214e883b14b 100644 > --- a/net/core/sock.c > +++ b/net/core/sock.c > @@ -3652,9 +3652,15 @@ void sock_def_readable(struct sock *sk) > > rcu_read_lock(); > wq = rcu_dereference(sk->sk_wq); > - if (skwq_has_sleeper(wq)) > - wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN | EPOLLPRI | > + if (skwq_has_sleeper(wq)) { > + if (sock_flag(sk, SOCK_SYNC_WAKEUP)) { > + wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN | EPOLLPRI | > + EPOLLRDNORM | EPOLLRDBAND); > + } else { > + wake_up_interruptible_poll(&wq->wait, EPOLLIN | EPOLLPRI | > EPOLLRDNORM | EPOLLRDBAND); > + } > + } > sk_wake_async_rcu(sk, SOCK_WAKE_WAITD, POLL_IN); > rcu_read_unlock(); > } > @@ -3670,9 +3676,15 @@ static void sock_def_write_space(struct sock *sk) > */ > if (sock_writeable(sk)) { > wq = rcu_dereference(sk->sk_wq); > - if (skwq_has_sleeper(wq)) > - wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT | > + if (skwq_has_sleeper(wq)) { > + if (sock_flag(sk, SOCK_SYNC_WAKEUP)) { > + wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT | > + EPOLLWRNORM | EPOLLWRBAND); > + } else { > + wake_up_interruptible_poll(&wq->wait, EPOLLOUT | > EPOLLWRNORM | EPOLLWRBAND); > + } > + } > > /* Should agree with poll, otherwise some programs break */ > sk_wake_async_rcu(sk, SOCK_WAKE_SPACE, POLL_OUT); > @@ -3695,10 +3707,15 @@ static void sock_def_write_space_wfree(struct sock *sk, int wmem_alloc) > > /* rely on refcount_sub from sock_wfree() */ > smp_mb__after_atomic(); > - if (wq && waitqueue_active(&wq->wait)) > - wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT | > + if (wq && waitqueue_active(&wq->wait)) { > + if (sock_flag(sk, SOCK_SYNC_WAKEUP)) { > + wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT | > EPOLLWRNORM | EPOLLWRBAND); > - > + } else { > + wake_up_interruptible_poll(&wq->wait, EPOLLOUT | > + EPOLLWRNORM | EPOLLWRBAND); > + } > + } > /* Should agree with poll, otherwise some programs break */ > sk_wake_async_rcu(sk, SOCK_WAKE_SPACE, POLL_OUT); > } > diff --git a/net/sctp/socket.c b/net/sctp/socket.c > index c7b9e325ec1c..9cb3432f065a 100644 > --- a/net/sctp/socket.c > +++ b/net/sctp/socket.c > @@ -9348,9 +9348,15 @@ void sctp_data_ready(struct sock *sk) > > rcu_read_lock(); > wq = rcu_dereference(sk->sk_wq); > - if (skwq_has_sleeper(wq)) > - wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN | > + if (skwq_has_sleeper(wq)) { > + if (sock_flag(sk, SOCK_SYNC_WAKEUP)) { > + wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN | > + EPOLLRDNORM | EPOLLRDBAND); > + } else { > + wake_up_interruptible_poll(&wq->wait, EPOLLIN | > EPOLLRDNORM | EPOLLRDBAND); > + } > + } > sk_wake_async_rcu(sk, SOCK_WAKE_WAITD, POLL_IN); > rcu_read_unlock(); > } > diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c > index b5db69073e20..1a6ea2e30769 100644 > --- a/net/smc/af_smc.c > +++ b/net/smc/af_smc.c > @@ -819,10 +819,10 @@ static void smc_fback_wakeup_waitqueue(struct smc_sock *smc, void *key) > wake_up_interruptible_all(&wq->wait); > } else { > flags = key_to_poll(key); > - if (flags & (EPOLLIN | EPOLLOUT)) > + if (flags & (EPOLLIN | EPOLLOUT) && sock_flag(&smc->sk, SOCK_SYNC_WAKEUP)) > /* sk_data_ready or sk_write_space */ > wake_up_interruptible_sync_poll(&wq->wait, flags); > - else if (flags & EPOLLERR) > + else > /* sk_error_report */ > wake_up_interruptible_poll(&wq->wait, flags); > } > diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c > index c1d9b923938d..4e288a2364d2 100644 > --- a/net/smc/smc_rx.c > +++ b/net/smc/smc_rx.c > @@ -39,9 +39,15 @@ static void smc_rx_wake_up(struct sock *sk) > /* called already in smc_listen_work() */ > rcu_read_lock(); > wq = rcu_dereference(sk->sk_wq); > - if (skwq_has_sleeper(wq)) > - wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN | EPOLLPRI | > + if (skwq_has_sleeper(wq)) { > + if (sock_flag(sk, SOCK_SYNC_WAKEUP)) { > + wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN | EPOLLPRI | > EPOLLRDNORM | EPOLLRDBAND); > + } else { > + wake_up_interruptible_poll(&wq->wait, EPOLLIN | EPOLLPRI | > + EPOLLRDNORM | EPOLLRDBAND); > + } > + } > sk_wake_async_rcu(sk, SOCK_WAKE_WAITD, POLL_IN); > if ((sk->sk_shutdown == SHUTDOWN_MASK) || > (sk->sk_state == SMC_CLOSED)) > diff --git a/net/tipc/socket.c b/net/tipc/socket.c > index e564341e0216..9fa83a89882c 100644 > --- a/net/tipc/socket.c > +++ b/net/tipc/socket.c > @@ -2116,9 +2116,15 @@ static void tipc_write_space(struct sock *sk) > > rcu_read_lock(); > wq = rcu_dereference(sk->sk_wq); > - if (skwq_has_sleeper(wq)) > - wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT | > + if (skwq_has_sleeper(wq)) { > + if (sock_flag(sk, SOCK_SYNC_WAKEUP)) { > + wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT | > EPOLLWRNORM | EPOLLWRBAND); > + } else { > + wake_up_interruptible_poll(&wq->wait, EPOLLOUT | > + EPOLLWRNORM | EPOLLWRBAND); > + } > + } > rcu_read_unlock(); > } > > @@ -2134,9 +2140,15 @@ static void tipc_data_ready(struct sock *sk) > > rcu_read_lock(); > wq = rcu_dereference(sk->sk_wq); > - if (skwq_has_sleeper(wq)) > - wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN | > - EPOLLRDNORM | EPOLLRDBAND); > + if (skwq_has_sleeper(wq)) { > + if (sock_flag(sk, SOCK_SYNC_WAKEUP)) { > + wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN | > + EPOLLRDNORM | EPOLLRDBAND); > + } else { > + wake_up_interruptible_poll(&wq->wait, EPOLLIN | > + EPOLLRDNORM | EPOLLRDBAND); > + } > + } > rcu_read_unlock(); > } > > diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c > index f7a9d55eee8a..15ebcc2d9d58 100644 > --- a/net/unix/af_unix.c > +++ b/net/unix/af_unix.c > @@ -601,9 +601,15 @@ static void unix_write_space(struct sock *sk) > rcu_read_lock(); > if (unix_writable(sk, READ_ONCE(sk->sk_state))) { > wq = rcu_dereference(sk->sk_wq); > - if (skwq_has_sleeper(wq)) > - wake_up_interruptible_sync_poll(&wq->wait, > - EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND); > + if (skwq_has_sleeper(wq)) { > + if (sock_flag(sk, SOCK_SYNC_WAKEUP)) { > + wake_up_interruptible_sync_poll(&wq->wait, > + EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND); > + } else { > + wake_up_interruptible_poll(&wq->wait, > + EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND); > + } > + } > sk_wake_async_rcu(sk, SOCK_WAKE_SPACE, POLL_OUT); > } > rcu_read_unlock(); > @@ -2603,11 +2609,15 @@ int __unix_dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t size, > goto out; > } > > - if (wq_has_sleeper(&u->peer_wait)) > - wake_up_interruptible_sync_poll(&u->peer_wait, > - EPOLLOUT | EPOLLWRNORM | > - EPOLLWRBAND); > - > + if (wq_has_sleeper(&u->peer_wait)) { > + if (sock_flag(sk, SOCK_SYNC_WAKEUP)) { > + wake_up_interruptible_sync_poll(&u->peer_wait, > + EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND); > + } else { > + wake_up_interruptible_poll(&u->peer_wait, > + EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND); > + } > + } > if (msg->msg_name) { > unix_copy_addr(msg, skb->sk); > Would it make sense to write a macro or a wrapper function do the same instead of sprinkling the same at all the places? similar comment for patch 1. IMHO, it would make it easier to read.