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  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]
Date:	Mon, 5 Nov 2012 16:41:49 +0800
From:	Cong Wang <>
To:	Stephen Hemminger <>
Cc:	Paolo Valente <>,,
	David Miller <>,
	LKML <>,
	Linux Kernel Network Developers <>,,
Subject: Re: [PATCH RFC] pkt_sched: enable QFQ to support TSO/GSO

On Tue, Oct 30, 2012 at 10:24 PM, Stephen Hemminger
<> wrote:
> On Tue, 30 Oct 2012 07:00:56 +0100
> Paolo Valente <> wrote:
>> Hi,
>> if the max packet size for some class (configured through tc) is
>> violated by the actual size of the packets of that class, then QFQ
>> would not schedule classes correctly, and the data structures
>> implementing the bucket lists may get corrupted. This problem occurs
>> with TSO/GSO even if the max packet size is set to the MTU, and is,
>> e.g., the cause of the failure reported in [1]. Two patches have been
>> proposed to solve this problem in [2], one of them is a preliminary
>> version of this patch.
>> This patch addresses the above issues by: 1) setting QFQ parameters to
>> proper values for supporting TSO/GSO (in particular, setting the
>> maximum possible packet size to 64KB), 2) automatically increasing the
>> max packet size for a class, lmax, when a packet with a larger size
>> than the current value of lmax arrives.
>> The drawback of the first point is that the maximum weight for a class
>> is now limited to 4096, which is equal to 1/16 of the maximum weight
>> sum.
>> Finally, this patch also forcibly caps the timestamps of a class if
>> they are too high to be stored in the bucket list. This capping, taken
>> from QFQ+ [3], handles the unfrequent case described in the comment to
>> the function slot_insert.
>> [1]
>> [2]
>> [3]
>> Signed-off-by: Paolo Valente <>
>> Tested-by: Cong Wang <>
> Acked-by: Stephen Hemminger <>

David, could you take this patch? Stephen acked it.

To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to
More majordomo info at

Powered by blists - more mailing lists