Re: [PATCH v3] IB/ipoib: Scatter-Gather support in connected mode

[Yuval Shaia <yuval.shaia-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>]

On Mon, May 11, 2015 at 01:40:07PM +0200, Yann Droneaud wrote:
> Hi,
> 
> Le lundi 11 mai 2015 à 03:04 -0700, Yuval Shaia a écrit :
> > By default, IPoIB-CM driver uses 64k MTU. Larger MTU gives better performance.
> > This MTU plus overhead puts the memory allocation for IP based packets at 32
> > 4k pages (order 5), which have to be contiguous.
> > When the system memory under pressure, it was observed that allocating 128k
> > contiguous physical memory is difficult and causes serious errors (such as
> > system becomes unusable).
> > 
> > This enhancement resolve the issue by removing the physically contiguous memory
> > requirement using Scatter/Gather feature that exists in Linux stack.
> > 
> > With this fix Scatter-Gather will be supported also in connected mode.
> > 
> > This change reverts the some of the change made in commit
> > e112373fd6aa280bd2cbc0d5cc3809115325a1be
> > ("IPoIB/cm: Reduce connected mode TX object size)".
> > 
> > The ability to use SG in IPoIB CM is possible because the coupling
> > between NETIF_F_SG and NETIF_F_CSUM was removed in commit
> > ec5f061564238892005257c83565a0b58ec79295
> > ("net: Kill link between CSUM and SG features.")
> > 
> > Signed-off-by: Yuval Shaia <yuval.shaia-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
> > ---
> > v2: Enhance commit log message
> > 
> > I'd like to thank John Sobecki <john.sobecki-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> and
> > Christian Marie <christian-x8YiTEMPTCFhl2p70BpVqQ@public.gmane.org> for helping me with reviewing this patch.
> > I will be glad if you can ACK it.
> > 
> > v3: Add an empty line to start a new paragraph and use 12 hex-digits identifier
> 
> Thanks, but you don't have to use the full commit identifier, 12
> characters were enough.
Will do.
> 
> Anyway, you haven't addressed the comments embedded in the patch in my
> reply [1] to your v2 patch.
Changing comments was quite easy, the rest will take a bit more, v4 will address it.
> 
> [1]
> http://marc.info/?i=1431335754.25060.26.camel-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org
> http://mid.gmane.org/1431335754.25060.26.camel-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org
> 
> Regards.
> 
> -- 
> Yann Droneaud
> OPTEYA
> 
> 
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