Subject: Re: [PATCH] ethernet/arc/arc_emac: Fix huge delays in large file copies

From: greg Kroah-Hartman <[email-masked]>
Date: Mon, 16 Sep 2013 12:40:12 -0700

On Mon, Sep 16, 2013 at 11:13:48AM +0530, Vineet Gupta wrote:
> On 09/10/2013 11:57 AM, Vineet Gupta wrote:
> > On 09/05/2013 11:55 PM, David Miller wrote:
> >> From: Vineet Gupta <[email-masked]>
> >> Date: Wed, 4 Sep 2013 17:17:15 +0530
> >>
> >>> copying large files to a NFS mounted host was taking absurdly large
> >>> time.
> >>>
> >>> Turns out that TX BD reclaim had a sublte bug.
> >>>
> >>> Loop starts off from @txbd_dirty cursor and stops when it hits a BD
> >>> still in use by controller. However when it stops it needs to keep the
> >>> cursor at that very BD to resume scanning in next iteration. However it
> >>> was erroneously incrementing the cursor, causing the next scan(s) to
> >>> fail too, unless the BD chain was completely drained out.
> >>>
> >>> [ARCLinux]$ ls -l -sh /disk/log.txt
> >>>  17976 -rw-r--r--    1 root     root       17.5M Sep  /disk/log.txt
> >>>
> >>> ========== Before =====================
> >>> [ARCLinux]$ time cp /disk/log.txt /mnt/.
> >>> real    31m 7.95s
> >>> user    0m 0.00s
> >>> sys     0m 0.10s
> >>>
> >>> ========== After =====================
> >>> [ARCLinux]$ time cp /disk/log.txt /mnt/.
> >>> real    0m 24.33s
> >>> user    0m 0.00s
> >>> sys     0m 0.19s
> >>>
> >>> Signed-off-by: Vineet Gupta <[email-masked]>
> >>
> >> Applied.
> >>
> > 
> > Hi Greg,
> > 
> > This needs a stable backport (3.11).
> > Mainline commit 27082ee1b92f4d41e78b85
> > 
> > Thx,
> > -Vineet
> 
> Hi Greg,
> 
> I didn't spot this one in your stable-queue for 3.11.
> Please apply.

Network patches for the stable tree needs to go through the networking
maintainer.  Please let them know about this and they will forward it on
to me if needed.

thanks,

greg k-h