From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C8203379960 for ; Thu, 6 Aug 2026 16:46:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786034802; cv=none; b=ifoddDsa9i3S8PsrfDulBvtHrHLJ8RjZ649Pu4aLO23bEyzqtgjIMWhgDK1sHtb5XtiDSwJn2WSuZI5WuJEYCHSdFTB0Tt0PD10qQjqEU9aWtAO03uu25WxTjFjhXqnnU/5KPFwjwstuDqWb6F7QzX60sIbjQcCBWyPMulQtfEg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786034802; c=relaxed/simple; bh=73PjkmVxvGgNHF+lJCg53zVw6sB4ilPVti4TtsHuc+Q=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=UWoKXuqmHeEYLOnvYXFmB3rpciWmr+0bWYunU0Rx791PuZRZo2jSnJvgU3+nJs3VXieLIFTI9yEZyKJkj0gQnOPUw8Tek9RQ249tMTmObol5pSm4yFyIza++87245tbfy4E90elEE9lK/he8jW0T1NzqXKcO58M8gMwEUDK+Dck= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QnjQPSW+; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QnjQPSW+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 380B11F00A3A; Thu, 6 Aug 2026 16:46:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786034796; bh=HEILB+hVmIf+AGLYg7yQOwLYR1h1+h8jh4vfqNXqMTI=; h=Date:Subject:To:References:From:In-Reply-To; b=QnjQPSW+MrqoItkd2GuOXZhbGiOxx4LChgiXtSsoLilB54gF7urHqkbiRtz4oTKYz h0tyONJEayLNQehQKyjVw94uHvHfK1z7wDoTVohA77N36gtoWUk4FZHBl039Pv9Au4 rfg+YBXYHU583vHpDhC+gklxRu47QgGD/lyEjbd/HpFR3BtgfKWYt0BZP8BmdHXu28 0eRIZxkA3bABQQ0xfjyoa/S3VNEfS7Gcsshvx28X+XX8jdXEWeMRUC+Cn7hJKXSCpq 1ACQbteN3tIQi3CZNbSYd4FJ0dIbUQO5ZazbITz0fom30rZR2x49O7letAatQRkvGQ Bv7yMRQMst0Mg== Message-ID: Date: Thu, 6 Aug 2026 18:46:34 +0200 Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH v2 mptcp-next 7/7] mptcp: implemented OoO queue pruning Content-Language: fr To: Paolo Abeni , mptcp@lists.linux.dev References: <80572775-6e76-4c79-83e2-efdedbd3f3b8@redhat.com> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; keydata= xsFNBFXj+ekBEADxVr99p2guPcqHFeI/JcFxls6KibzyZD5TQTyfuYlzEp7C7A9swoK5iCvf YBNdx5Xl74NLSgx6y/1NiMQGuKeu+2BmtnkiGxBNanfXcnl4L4Lzz+iXBvvbtCbynnnqDDqU c7SPFMpMesgpcu1xFt0F6bcxE+0ojRtSCZ5HDElKlHJNYtD1uwY4UYVGWUGCF/+cY1YLmtfb WdNb/SFo+Mp0HItfBC12qtDIXYvbfNUGVnA5jXeWMEyYhSNktLnpDL2gBUCsdbkov5VjiOX7 CRTkX0UgNWRjyFZwThaZADEvAOo12M5uSBk7h07yJ97gqvBtcx45IsJwfUJE4hy8qZqsA62A nTRflBvp647IXAiCcwWsEgE5AXKwA3aL6dcpVR17JXJ6nwHHnslVi8WesiqzUI9sbO/hXeXw TDSB+YhErbNOxvHqCzZEnGAAFf6ges26fRVyuU119AzO40sjdLV0l6LE7GshddyazWZf0iac nEhX9NKxGnuhMu5SXmo2poIQttJuYAvTVUNwQVEx/0yY5xmiuyqvXa+XT7NKJkOZSiAPlNt6 VffjgOP62S7M9wDShUghN3F7CPOrrRsOHWO/l6I/qJdUMW+MHSFYPfYiFXoLUZyPvNVCYSgs 3oQaFhHapq1f345XBtfG3fOYp1K2wTXd4ThFraTLl8PHxCn4ywARAQABzSRNYXR0aGlldSBC YWVydHMgPG1hdHR0YmVAa2VybmVsLm9yZz7CwZEEEwEIADsCGwMFCwkIBwIGFQoJCAsCBBYC AwECHgECF4AWIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZUDpDAIZAQAKCRD2t4JPQmmgcz33 EACjROM3nj9FGclR5AlyPUbAq/txEX7E0EFQCDtdLPrjBcLAoaYJIQUV8IDCcPjZMJy2ADp7 /zSwYba2rE2C9vRgjXZJNt21mySvKnnkPbNQGkNRl3TZAinO1Ddq3fp2c/GmYaW1NWFSfOmw MvB5CJaN0UK5l0/drnaA6Hxsu62V5UnpvxWgexqDuo0wfpEeP1PEqMNzyiVPvJ8bJxgM8qoC cpXLp1Rq/jq7pbUycY8GeYw2j+FVZJHlhL0w0Zm9CFHThHxRAm1tsIPc+oTorx7haXP+nN0J iqBXVAxLK2KxrHtMygim50xk2QpUotWYfZpRRv8dMygEPIB3f1Vi5JMwP4M47NZNdpqVkHrm jvcNuLfDgf/vqUvuXs2eA2/BkIHcOuAAbsvreX1WX1rTHmx5ud3OhsWQQRVL2rt+0p1DpROI 3Ob8F78W5rKr4HYvjX2Inpy3WahAm7FzUY184OyfPO/2zadKCqg8n01mWA9PXxs84bFEV2mP VzC5j6K8U3RNA6cb9bpE5bzXut6T2gxj6j+7TsgMQFhbyH/tZgpDjWvAiPZHb3sV29t8XaOF BwzqiI2AEkiWMySiHwCCMsIH9WUH7r7vpwROko89Tk+InpEbiphPjd7qAkyJ+tNIEWd1+MlX ZPtOaFLVHhLQ3PLFLkrU3+Yi3tXqpvLE3gO3LM7BTQRV4/npARAA5+u/Sx1n9anIqcgHpA7l 5SUCP1e/qF7n5DK8LiM10gYglgY0XHOBi0S7vHppH8hrtpizx+7t5DBdPJgVtR6SilyK0/mp 9nWHDhc9rwU3KmHYgFFsnX58eEmZxz2qsIY8juFor5r7kpcM5dRR9aB+HjlOOJJgyDxcJTwM 1ey4L/79P72wuXRhMibN14SX6TZzf+/XIOrM6TsULVJEIv1+NdczQbs6pBTpEK/G2apME7vf mjTsZU26Ezn+LDMX16lHTmIJi7Hlh7eifCGGM+g/AlDV6aWKFS+sBbwy+YoS0Zc3Yz8zrdbi Kzn3kbKd+99//mysSVsHaekQYyVvO0KD2KPKBs1S/ImrBb6XecqxGy/y/3HWHdngGEY2v2IP Qox7mAPznyKyXEfG+0rrVseZSEssKmY01IsgwwbmN9ZcqUKYNhjv67WMX7tNwiVbSrGLZoqf Xlgw4aAdnIMQyTW8nE6hH/Iwqay4S2str4HZtWwyWLitk7N+e+vxuK5qto4AxtB7VdimvKUs x6kQO5F3YWcC3vCXCgPwyV8133+fIR2L81R1L1q3swaEuh95vWj6iskxeNWSTyFAVKYYVskG V+OTtB71P1XCnb6AJCW9cKpC25+zxQqD2Zy0dK3u2RuKErajKBa/YWzuSaKAOkneFxG3LJIv Hl7iqPF+JDCjB5sAEQEAAcLBXwQYAQIACQUCVeP56QIbDAAKCRD2t4JPQmmgc5VnD/9YgbCr HR1FbMbm7td54UrYvZV/i7m3dIQNXK2e+Cbv5PXf19ce3XluaE+wA8D+vnIW5mbAAiojt3Mb 6p0WJS3QzbObzHNgAp3zy/L4lXwc6WW5vnpWAzqXFHP8D9PTpqvBALbXqL06smP47JqbyQxj Xf7D2rrPeIqbYmVY9da1KzMOVf3gReazYa89zZSdVkMojfWsbq05zwYU+SCWS3NiyF6QghbW voxbFwX1i/0xRwJiX9NNbRj1huVKQuS4W7rbWA87TrVQPXUAdkyd7FRYICNW+0gddysIwPoa KrLfx3Ba6Rpx0JznbrVOtXlihjl4KV8mtOPjYDY9u+8x412xXnlGl6AC4HLu2F3ECkamY4G6 UxejX+E6vW6Xe4n7H+rEX5UFgPRdYkS1TA/X3nMen9bouxNsvIJv7C6adZmMHqu/2azX7S7I vrxxySzOw9GxjoVTuzWMKWpDGP8n71IFeOot8JuPZtJ8omz+DZel+WCNZMVdVNLPOd5frqOv mpz0VhFAlNTjU1Vy0CnuxX3AM51J8dpdNyG0S8rADh6C8AKCDOfUstpq28/6oTaQv7QZdge0 JY6dglzGKnCi/zsmp2+1w559frz4+IC7j/igvJGX4KDDKUs0mlld8J2u2sBXv7CGxdzQoHaz lzVbFe7fduHbABmYz9cefQpO7wDE/Q== Organization: NGI0 Core In-Reply-To: <80572775-6e76-4c79-83e2-efdedbd3f3b8@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 06/08/2026 18:42, Paolo Abeni wrote: > On 8/6/26 4:45 PM, Paolo Abeni wrote: >> When moving incoming skbs in the msk receive queue and the latter >> is above limits, prune it as needed quite alike what TCP is doing >> at the subflow level. The main difference relies in the stop condition: >> since MPTCP does not perform collapsing, it's better off dropping the >> bare minimum to fit the (newer) incoming packet. >> >> Signed-off-by: Paolo Abeni >> Tested-by: Gang Yan >> Reviewed-by: Matthieu Baerts (NGI0) >> --- >> v -> v: >> - prune only for new data >> - reorganize the code to follow more closely TCP >> --- >> net/mptcp/mib.c | 1 + >> net/mptcp/mib.h | 1 + >> net/mptcp/protocol.c | 81 ++++++++++++++++++++++++++++++++++++++------ >> 3 files changed, 73 insertions(+), 10 deletions(-) >> >> diff --git a/net/mptcp/mib.c b/net/mptcp/mib.c >> index ef65e2df709f..2569385bab7c 100644 >> --- a/net/mptcp/mib.c >> +++ b/net/mptcp/mib.c >> @@ -87,6 +87,7 @@ static const struct snmp_mib mptcp_snmp_list[] = { >> SNMP_MIB_ITEM("WinProbe", MPTCP_MIB_WINPROBE), >> SNMP_MIB_ITEM("BacklogDrop", MPTCP_MIB_BACKLOGDROP), >> SNMP_MIB_ITEM("RcvPruned", MPTCP_MIB_RCVPRUNED), >> + SNMP_MIB_ITEM("OFOPruned", MPTCP_MIB_OFOPRUNED), >> }; >> >> /* mptcp_mib_alloc - allocate percpu mib counters >> diff --git a/net/mptcp/mib.h b/net/mptcp/mib.h >> index 9271205f682e..3a3425e258a7 100644 >> --- a/net/mptcp/mib.h >> +++ b/net/mptcp/mib.h >> @@ -90,6 +90,7 @@ enum linux_mptcp_mib_field { >> MPTCP_MIB_WINPROBE, /* MPTCP-level zero window probe */ >> MPTCP_MIB_BACKLOGDROP, /* Backlog over memory limit */ >> MPTCP_MIB_RCVPRUNED, /* Dropped due to memory constraints */ >> + MPTCP_MIB_OFOPRUNED, /* MPTCP-level OoO queue pruned */ >> __MPTCP_MIB_MAX >> }; >> >> diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c >> index 63f2c18bc01f..ec874d2ead6a 100644 >> --- a/net/mptcp/protocol.c >> +++ b/net/mptcp/protocol.c >> @@ -242,6 +242,65 @@ static bool mptcp_rcvbuf_grow(struct sock *sk, u32 newval) >> return false; >> } >> >> +/* "Inspired" from the TCP version; main difference: stop as soon as the MPTCP >> + * socket is under memory limit. >> + */ >> +static void mptcp_prune_ofo_queue(struct sock *sk, >> + const struct sk_buff *in_skb) >> +{ >> + struct mptcp_sock *msk = mptcp_sk(sk); >> + struct rb_node *node, *prev; >> + bool pruned = false; >> + u64 mem; >> + >> + if (RB_EMPTY_ROOT(&msk->out_of_order_queue)) >> + return; >> + >> + node = &msk->ooo_last_skb->rbnode; >> + >> + do { >> + struct sk_buff *skb = rb_to_skb(node); >> + >> + /* Stop pruning if the incoming skb would land in OoO tail. */ >> + if (after64(MPTCP_SKB_CB(in_skb)->map_seq, >> + MPTCP_SKB_CB(skb)->map_seq)) >> + break; >> + >> + pruned = true; >> + prev = rb_prev(node); >> + rb_erase(node, &msk->out_of_order_queue); >> + mptcp_drop(sk, skb); >> + msk->ooo_last_skb = rb_to_skb(prev); >> + >> + mem = (unsigned int)sk_rmem_alloc_get(sk); >> + if (mem <= sk->sk_rcvbuf) >> + break; >> + >> + node = prev; >> + } while (node); >> + >> + if (pruned) >> + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_OFOPRUNED); >> +} >> + >> +/* The stack can't drop packets for fallback socket at the msk level, or the >> + * stream will break. >> + */ >> +static bool mptcp_can_ingest(const struct sock *sk) >> +{ >> + return unlikely(sk_rmem_alloc_get(sk) <= READ_ONCE(sk->sk_rcvbuf)) || >> + __mptcp_check_fallback(mptcp_sk(sk)); > The above should obviously be: 'likely(...)' > > @Matttbe: please LMK if you prefer a repost or you could adjust that > while applying to the export branch. No problem, I can adjust them when applying them (if there are no other big modifications required, but I guess no). Cheers, Matt -- Sponsored by the NGI0 Core fund.