netdev - Re: [PATCH v2] net: batch skb dequeueing from softnet input_pkt

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: <x2z412e6f7f1004130638hb72b121cne442d722427de5a4@mail.gmail.com>
Date:	Tue, 13 Apr 2010 21:38:32 +0800
From:	Changli Gao <xiaosuo@...il.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org
Subject: Re: [PATCH v2] net: batch skb dequeueing from softnet input_pkt_queue

On Tue, Apr 13, 2010 at 9:21 PM, Eric Dumazet <eric.dumazet@...il.com> wrote:
>
> This is a problem of cooperation between flush_backlog() and
> process_backlog(). Dont allow flush_backlog() to return if
> process_backlog() is running. Exactly as before, but lock acquisition
> done in flush_backlog() should be a bit smarter.
>

flush_backlog() is called in IRQ context. Unless you disable irq in
process_backlog(), you can't block flush_backlog().

>
>> Oh, my GOD. When RPS is enabled, if flush_backlog(eth0) is called on
>> CPU1 when a skb0(eth0) is dequeued from CPU0's softnet and isn't
>> queued to CPU1's softnet, what will happen?
>>
>
> I am a bit lost here. flush_backlog() drops skbs, not requeue them.
>

I mean flush_backlog() don't drop all the packets, whose dev point to
a special net_device and can't be processed before the net_device
disappers.

-- 
Regards，
Changli Gao(xiaosuo@...il.com)
--
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