From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.72 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793949700; b=RLc7LHq4WVtc25mc/zy9Wnsb2My1xWCMD/cNHpL01ahhAFXWU8FOAnJYLifla/Dpvsrf eu0+4ii5EOISHVDDlZEjQFdnEupqL9+NIl9ao1lIXmOrwoVF9U9vYu9I8isMpFD4tE2lk l+EcJ19VYF7M4isfFUcwyhS+XrL3/59K8u5l79Er1meDg3eRE1B5knKzWLpmnnzYwg3iz PqiUaCwk8dNxqYuq5mZPhWWR/Y49lOQtSfxhKR+IAWneTGgLMcf5ntm2dJGipV7hs4Wq9 73k2aK03aCJZWa8LXH2kahkVVqibgIYFr7dkC0bxprjojsKilQ5XoU5LrU3VU8/ms7w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793949700; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=Q9YYTe4i+4Chs5+YJWhPl441drO/ZQz1qRAsGWnT09I=; b=4wPSrFt+/7CX5aUqpuGT891WB3SoiWKkBUsvGB/UCGVxNoTZG/AEvTW5pmenbJ4iD5+y euaxAIkkFK3XhwqsLUoXz/iOX2y+jpWv4IjESOb4ohu0bHCuefrhLNLVVNDiLGxFfwPpW LPdgDRwSe6myYbRM8PtFdOsc+NOy66TNOZgAbWi5nxSuwFXrCmvkzYWaOFeG2Ku61+bYf 2bbAkzgU5APoIW+BNU0K0qCTuL5Z2mOxBXKszAmugPM3kNEsx7w0Uhm00nBlsvs9/rxs+ 2G5NsroUiOqOddCSOdjM/nEFOLfQRJqoThxOmhl7HZBbdKLLVEOIDXDz7+u4L8sH9cQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=CLjn+X7o; arc=none smtp.remote-ip=91.218.175.72 Received: from mta0.migadu.com (out-72.mta0.migadu.com [91.218.175.72]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 674D0606D801 for ; Fri, 6 Nov 2026 07:21:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 674D0606D801 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=CLjn+X7o X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=RqSggLrOpNcBQyi3pO63AlsgM6jzSKYB2+97JEfd7P8=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793949697; v=1; x=1794554497; b=CLjn+X7oZ1Li6Tw+7+7sk9d54FQu32SslMOusYl8ds8/SJYrAf6MYeMu6y0FSSfv7viPmM8Z awmqNbBtDH6+2/OUuHC19G1gpjGGWudQituxfP6kD/msJPT3YxO2o6m8Ca98VaHTBGj39jl7yZT SyEWav4fM8I7rDVsIg7A7Xp8= X-Envelope-To: linux-kernel@vger.kernel.org Received: by mta10.migadu.com with ESMTPS id 984ea10fba56dac9; Fri, 06 Nov 2026 07:21:37 +0000 X-Mizu-Trace-ID: 984ea10fba56dac9 X-Migadu-Flow: FLOW_OUT Date: Fri, 6 Nov 2026 15:21:26 +0800 From: Hangbin Liu To: ramses@well-founded.dev Cc: Jay Vosburgh , Andrew Lunn , "David S. Miller" , Jakub Kicinski , Paolo Abeni , Jiri Bohac , Eric Dumazet , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Nikolay Aleksandrov Subject: Re: [PATCH net v5 2/2] bonding: give a slave that starts UP a full arp_missed_max window Message-ID: References: <20261030-bonding-last-rx-v5-0-0b9b653f2f94@well-founded.dev> <20261030-bonding-last-rx-v5-2-0b9b653f2f94@well-founded.dev> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261030-bonding-last-rx-v5-2-0b9b653f2f94@well-founded.dev> On Fri, Oct 30, 2026 at 03:51:16PM +0100, Ramses de Norre via B4 Relay wrote: > From: Ramses de Norre > > The ARP monitor marks an UP slave DOWN once jiffies passes > last_rx + arp_missed_max * arp_interval + arp_interval/2. bond_enslave() > seeds last_rx one arp_interval (plus a tick) in the past, which brings > the down deadline of a slave that starts UP forward by one interval > compared to what arp_missed_max promises. > > Active-backup mode hides this with a grace period after enslavement in > bond_ab_arp_inspect(). Load-balance mode has no grace period after > enslavement. With arp_missed_max=1 the deadline is half an interval > after enslavement, and the first monitor run checks the slave before it > sends the first probe. If that run lands in the second half of the > interval, a healthy slave is reported "interface is now down" and comes > back UP on the next run. > > Seed a slave that starts UP with last_link_up instead, so it gets a full > arp_missed_max window for its first reply. bond_arp_rcv() and > bond_na_rcv() only trust ARPs seen on backup slaves once the active > slave's last_rx is after its last_link_up. A seed equal to last_link_up > keeps that check false until a real reply arrives, as it is today. > > This only covers a slave enslaved while the ARP monitor is running. > When the monitor starts later, from bond_open() or when arp_interval is > set at runtime, the seed is still as old as the time since enslavement, > as it was before this patch. > > Fixes: 5944b5abd864 ("Bonding: add arp_missed_max option") > Signed-off-by: Ramses de Norre > --- > drivers/net/bonding/bond_main.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c > index 2f5638f4d3a78..84eafb607c370 100644 > --- a/drivers/net/bonding/bond_main.c > +++ b/drivers/net/bonding/bond_main.c > @@ -2158,9 +2158,13 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev, > new_slave->last_rx = jiffies - > (2 * msecs_to_jiffies(bond->params.arp_interval) + 1); > } else { > + /* Give a slave that starts UP a full arp_missed_max window. > + * Not seeding it later than last_link_up keeps bond_arp_rcv() > + * from trusting ARPs on backup slaves before the active one > + * got a reply. > + */ > new_slave->last_link_up = jiffies; > - new_slave->last_rx = jiffies - > - (msecs_to_jiffies(bond->params.arp_interval) + 1); > + new_slave->last_rx = new_slave->last_link_up; > } > for (i = 0; i < BOND_MAX_ARP_TARGETS; i++) > new_slave->target_last_arp_rx[i] = new_slave->last_rx; > > -- > 2.56.0 > > Sashiko reported some other issues during arp_target/arp_interval set. But none of these introduced by this patch. And we haven't received real user report about these issues. So for this patch Reviewed-by: Hangbin Liu