netdev - Re: [PATCH net V1 1/3] net/mlx4_en: Don't use irq_affinity_notifier to track changes in IRQ affinity map

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <53B27BF5.6080608@mellanox.com>
Date:	Tue, 1 Jul 2014 12:14:29 +0300
From:	Amir Vadai <amirv@...lanox.com>
To:	David Miller <davem@...emloft.net>, <amirv.mellanox@...il.com>
CC:	<eric.dumazet@...il.com>, <netdev@...r.kernel.org>,
	<ogerlitz@...lanox.com>, <yevgenyp@...lanox.com>,
	<tglx@...utronix.de>, <ben@...adent.org.uk>, <amira@...lanox.com>,
	<yuvala@...lanox.com>
Subject: Re: [PATCH net V1 1/3] net/mlx4_en: Don't use irq_affinity_notifier
 to track changes in IRQ affinity map

On 07/01/2014 06:33 AM, David Miller wrote:
> From: Amir Vadai <amirv.mellanox@...il.com>
> Date: Mon, 30 Jun 2014 11:34:22 +0300
>
>> On 6/30/2014 9:41 AM, Eric Dumazet wrote:
>>> You might want to drain whole queue instead of limiting to a 'budget',
>>> otherwise, a cpu might be stuck servicing (soft)irq for the TX
>>> completion, even if irq affinities say otherwise.
>>>
>>
>> TX completions are very quick compared to the skb preparation and
>> sending. Which is not the case for RX completions. Because of that, it
>> is very easy to reproduce the problem in RX flows, but we never had any
>> report of that problem in the TX flow.
>> I prefer not to spend time on the TX, since we plan to send a patch soon
>> to use the same NAPI for both TX and RX.
>
> It is always advised to completely ignore the budget for TX work, this is
> what we tell every driver author when discussion NAPI implementations.
>
> Please make your driver conform to this, thanks.
>

Ok.

Please continue the process on this V1 of the patchset. The fix to TX 
poll is not related to this patch - this patch is fixing a regression 
that broke aRFS in mlx4_en.

I will send a separate fix to purge all packets on TX work later on this 
week.

Thanks,
Amir
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html