Re: [PATCH v12 04/31] arm64/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT

[Laurent Dufour]

Le 23/04/2019 Ã 18:19, Mark Rutland a ÃcritÂ:
> On Tue, Apr 23, 2019 at 05:36:31PM +0200, Laurent Dufour wrote:
> > Le 18/04/2019 Ã 23:51, Jerome Glisse a ÃcritÂ:
> > > On Tue, Apr 16, 2019 at 03:41:56PM +0100, Mark Rutland wrote:
> > > > On Tue, Apr 16, 2019 at 04:31:27PM +0200, Laurent Dufour wrote:
> > > > > Le 16/04/2019 Ã 16:27, Mark Rutland a ÃcritÂ:
> > > > > > On Tue, Apr 16, 2019 at 03:44:55PM +0200, Laurent Dufour wrote:
> > > > > > > From: Mahendran Ganesh <opensource.ganesh@xxxxxxxxx>
> > > > > > >
> > > > > > > Set ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT for arm64. This
> > > > > > > enables Speculative Page Fault handler.
> > > > > > >
> > > > > > > Signed-off-by: Ganesh Mahendran <opensource.ganesh@xxxxxxxxx>
> > > > > >
> > > > > > This is missing your S-o-B.
> > > > >
> > > > > You're right, I missed that...
> > > > >
> > > > > > The first patch noted that the ARCH_SUPPORTS_* option was there because
> > > > > > the arch code had to make an explicit call to try to handle the fault
> > > > > > speculatively, but that isn't addeed until patch 30.
> > > > > >
> > > > > > Why is this separate from that code?
> > > > >
> > > > > Andrew was recommended this a long time ago for bisection purpose. This
> > > > > allows to build the code with CONFIG_SPECULATIVE_PAGE_FAULT before the code
> > > > > that trigger the spf handler is added to the per architecture's code.
> > > >
> > > > Ok. I think it would be worth noting that in the commit message, to
> > > > avoid anyone else asking the same question. :)
> > >
> > > Should have read this thread before looking at x86 and ppc :)
> > >
> > > In any case the patch is:
> > >
> > > Reviewed-by: JÃrÃme Glisse <jglisse@xxxxxxxxxx>
> >
> > Thanks Mark and JÃrÃme for reviewing this.
> >
> > Regarding the change in the commit message, I'm wondering if this would be
> > better to place it in the Series's letter head.
> >
> > But I'm fine to put it in each architecture's commit.
>
> I think noting it in both the cover letter and specific patches is best.
>
> Having something in the commit message means that the intent will be
> clear when the patch is viewed in isolation (e.g. as they will be once
> merged).
>
> All that's necessary is something like:
>
>    Note that this patch only enables building the common speculative page
>    fault code such that this can be bisected, and has no functional
>    impact. The architecture-specific code to make use of this and enable
>    the feature will be addded in a subsequent patch.

Thanks Mark, will do it this way.


> Thanks,
> Mark.