Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header,Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header,Re: [PATCH] IB/ipoib: move back the IB LL address into the

From: Doug Ledford Date: Thu, 13 Oct 2016 11:20:59 -0400 > We *had* a safe way to do that. It got broken. What about increasing > the size of skb->cb? Or adding a skb->dgid that is a > u8[INFINIBAND_ALEN]? Or a more generic skb->dest_ll_addr that is sized > to hold the

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header,Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

On 10/13/2016 10:43 AM, David Miller wrote: > From: Doug Ledford > Date: Thu, 13 Oct 2016 10:35:35 -0400 > >> On 10/13/2016 10:24 AM, David Miller wrote: >>> From: Paolo Abeni >>> Date: Tue, 11 Oct 2016 19:15:44 +0200 >>> After the commit

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

On Thu, 2016-10-13 at 10:24 -0400, David Miller wrote: > From: Paolo Abeni > Date: Tue, 11 Oct 2016 19:15:44 +0200 > > > After the commit 9207f9d45b0a ("net: preserve IP control block > > during GSO segmentation"), the GSO CB and the IPoIB CB conflict. > > That destroy the

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

From: Paolo Abeni Date: Tue, 11 Oct 2016 19:15:44 +0200 > After the commit 9207f9d45b0a ("net: preserve IP control block > during GSO segmentation"), the GSO CB and the IPoIB CB conflict. > That destroy the IPoIB address information cached there, > causing a severe performance

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

On 10/13/2016 10:24 AM, David Miller wrote: > From: Paolo Abeni > Date: Tue, 11 Oct 2016 19:15:44 +0200 > >> After the commit 9207f9d45b0a ("net: preserve IP control block >> during GSO segmentation"), the GSO CB and the IPoIB CB conflict. >> That destroy the IPoIB address

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header,Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

From: Doug Ledford Date: Thu, 13 Oct 2016 10:35:35 -0400 > On 10/13/2016 10:24 AM, David Miller wrote: >> From: Paolo Abeni >> Date: Tue, 11 Oct 2016 19:15:44 +0200 >> >>> After the commit 9207f9d45b0a ("net: preserve IP control block >>> during GSO

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

On 10/11/2016 2:50 PM, Doug Ledford wrote: > On 10/11/2016 2:30 PM, Jason Gunthorpe wrote: >> On Tue, Oct 11, 2016 at 02:17:51PM -0400, Doug Ledford wrote: >> >>> Well, not exactly. Even if we put 65520 into the scripts, the kernel >>> will silently drop it down to 65504. It actually won't

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

On 10/11/2016 2:30 PM, Jason Gunthorpe wrote: > On Tue, Oct 11, 2016 at 02:17:51PM -0400, Doug Ledford wrote: > >> Well, not exactly. Even if we put 65520 into the scripts, the kernel >> will silently drop it down to 65504. It actually won't require anyone >> change anything, they just won't

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

On Tue, Oct 11, 2016 at 02:17:51PM -0400, Doug Ledford wrote: > Well, not exactly. Even if we put 65520 into the scripts, the kernel > will silently drop it down to 65504. It actually won't require anyone > change anything, they just won't get the full value. I experimented > with this in the

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

On Tue, 2016-10-11 at 11:42 -0600, Jason Gunthorpe wrote: > On Tue, Oct 11, 2016 at 07:37:32PM +0200, Paolo Abeni wrote: > > On Tue, 2016-10-11 at 11:32 -0600, Jason Gunthorpe wrote: > > > On Tue, Oct 11, 2016 at 07:15:44PM +0200, Paolo Abeni wrote: > > > > > > > Also the connected mode maximum

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

On Tue, Oct 11, 2016 at 08:10:07PM +0200, Paolo Abeni wrote: > The first s/g fragment (the head buffer) is not allocated with the page > allocator, so perhaps there is some not too difficult/costly way out of > this. Keep in mind, there is nothing magic about the 16 SGL limit, other than we know

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

On 10/11/2016 2:10 PM, Paolo Abeni wrote: > On Tue, 2016-10-11 at 12:01 -0600, Jason Gunthorpe wrote: >>> AFAICS the max mtu is already underlying h/w dependent, how does such >>> differences are currently coped by ? (I'm sorry I lack some/a lot of IB >>> back-ground) >> >> It isn't h/w dependent.

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

On Tue, 2016-10-11 at 12:01 -0600, Jason Gunthorpe wrote: > > AFAICS the max mtu is already underlying h/w dependent, how does such > > differences are currently coped by ? (I'm sorry I lack some/a lot of IB > > back-ground) > > It isn't h/w dependent. In CM mode the MTU is 65520 because that is

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

On Tue, Oct 11, 2016 at 01:41:56PM -0400, Doug Ledford wrote: > declare the header. The problem then became that the sg setup is such > that we are limited to 16 4k pages for the sg array, so that header had > to come out of the 64k maximum mtu. Oh, that clarifies things.. Hum, so various

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

On 10/11/2016 1:32 PM, Jason Gunthorpe wrote: > On Tue, Oct 11, 2016 at 07:15:44PM +0200, Paolo Abeni wrote: > >> Also the connected mode maximum mtu is reduced by 16 bytes to >> cope with the increased hard header len. > > Changing the MTU is going to cause annoying interop problems, can you >

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

On Tue, Oct 11, 2016 at 07:37:32PM +0200, Paolo Abeni wrote: > On Tue, 2016-10-11 at 11:32 -0600, Jason Gunthorpe wrote: > > On Tue, Oct 11, 2016 at 07:15:44PM +0200, Paolo Abeni wrote: > > > > > Also the connected mode maximum mtu is reduced by 16 bytes to > > > cope with the increased hard

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

On Tue, 2016-10-11 at 11:32 -0600, Jason Gunthorpe wrote: > On Tue, Oct 11, 2016 at 07:15:44PM +0200, Paolo Abeni wrote: > > > Also the connected mode maximum mtu is reduced by 16 bytes to > > cope with the increased hard header len. > > Changing the MTU is going to cause annoying interop

Re: [PATCH] IB/ipoib: move back the IB LL address into the hard header

On Tue, Oct 11, 2016 at 07:15:44PM +0200, Paolo Abeni wrote: > Also the connected mode maximum mtu is reduced by 16 bytes to > cope with the increased hard header len. Changing the MTU is going to cause annoying interop problems, can you avoid this? Jason

[PATCH] IB/ipoib: move back the IB LL address into the hard header

After the commit 9207f9d45b0a ("net: preserve IP control block during GSO segmentation"), the GSO CB and the IPoIB CB conflict. That destroy the IPoIB address information cached there, causing a severe performance regression, as better described here: