Messages in this thread |  | | Date | Mon, 24 Feb 2014 15:08:31 +0000 | From | Zoltan Kiss <> | Subject | Re: [PATCH net-next v5 4/9] xen-netback: Change RX path for mapped SKB fragments |
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On 24/02/14 13:49, Zoltan Kiss wrote: > On 22/02/14 23:18, Zoltan Kiss wrote: >> On 18/02/14 17:45, Ian Campbell wrote: >>> On Mon, 2014-01-20 at 21:24 +0000, Zoltan Kiss wrote: >>> >>> Re the Subject: change how? Perhaps "handle foreign mapped pages on the >>> guest RX path" would be clearer. >> Ok, I'll do that. >> >>> >>>> RX path need to know if the SKB fragments are stored on pages from >>>> another >>>> domain. >>> Does this not need to be done either before the mapping change or at >>> the >>> same time? -- otherwise you have a window of a couple of commits where >>> things are broken, breaking bisectability. >> I can move this to the beginning, to keep bisectability. I've put it >> here originally because none of these makes sense without the >> previous patches. > Well, I gave it a close look: to move this to the beginning as a > separate patch I would need to put move a lot of definitions from the > first patch to here (ubuf_to_vif helper, xenvif_zerocopy_callback > etc.). That would be the best from bisect point of view, but from > patch review point of view even worse than now. So the only option I > see is to merge this with the first 2 patches, so it will be even bigger. Actually I was stupid, we can move this patch earlier and introduce stubs for those 2 functions. But for the another two patches (#6 and #8) it's still true that we can't move them before, only merge them into the main, as they heavily rely on the main patch. #6 is necessary for Windows frontends, as they are keen to send too many slots. #8 is quite a rare case, happens only if a guest wedge or malicious, and sits on the packet. So my question is still up: do you prefer perfect bisectability or more segmented patches which are not that pain to review?
> And based on that principle, patch #6 and #8 should be merged there as > well, as they solve corner cases introduced by the grant mapping. > I don't know how much the bisecting requirements are written in stone. > At this moment, all the separate patches compile, but after #2 there > are new problems solved in #4, #6 and #8. If someone bisect in the > middle of this range and run into these problems, they could quite > easily figure out what went wrong looking at the adjacent patches. So > I would recommend to keep this current order. > What's your opinion? > > Zoli
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