Re: [PATCH 1/3] KVM: X86: Add "nopvspin" parameter to disable PV spinlocks

[Zhenzhong Duan]

On 2019/10/3 0:47, Sean Christopherson wrote:
> On Tue, Oct 01, 2019 at 05:47:00PM +0800, Zhenzhong Duan wrote:
> > On 2019/10/1 16:39, Vitaly Kuznetsov wrote:
> > > Zhenzhong Duan<zhenzhong.duan@xxxxxxxxxx>  writes:
> > >
> > > > On 2019/9/30 23:41, Vitaly Kuznetsov wrote:
> > > > > Zhenzhong Duan<zhenzhong.duan@xxxxxxxxxx>   writes:
> > > > >
> > > > > > There are cases where a guest tries to switch spinlocks to bare metal
> > > > > > behavior (e.g. by setting "xen_nopvspin" on XEN platform and
> > > > > > "hv_nopvspin" on HYPER_V).
> > > > > >
> > > > > > That feature is missed on KVM, add a new parameter "nopvspin" to disable
> > > > > > PV spinlocks for KVM guest.
> > > > > >
> > > > > > This new parameter is also intended to replace "xen_nopvspin" and
> > > > > > "hv_nopvspin" in the future.
> > > > > Any reason to not do it right now? We will probably need to have compat
> > > > > code to support xen_nopvspin/hv_nopvspin too but emit a 'is deprecated'
> > > > > warning.
> > > > Sorry the description isn't clear, I'll fix it.
> > > >
> > > > I did the compat work in the other two patches.
> > > > [PATCH 2/3] xen: Mark "xen_nopvspin" parameter obsolete and map it to "nopvspin"
> > > > [PATCH 3/3] x86/hyperv: Mark "hv_nopvspin" parameter obsolete and map it to "nopvspin"
> > > For some reason I got CCed only on the first one and moreover,
> > The three patches have different maintainers/reviewers by get_maintainer.pl, I added
> > "Cc: maintainers/reviewers" to each patch then git-sendemail picked them automaticly.
> > I meaned to not disturb maintainers with the field they aren't in charge of. It looks
> > I'm wrong.
> >
> > So what's the correct way dealing with this? Should I send the whole patchset to all
> > the maintainers/reviewers related to all the patches?
> There's no one right answer to that question, folks have different
> preferences.  My general rule of thumb is to cc everyone on all patches
> unless the series is obnoxiously large *and* isolated to a specific part
> of the kernel.  The idea being that people are more likely to be annoyed
> if they can't find all patches in a relatively small series (this case)
> than they are about receiving a mail or two that they don't care about.
>
> At a minimum I would cc everyone involved on the cover letter, and cc the
> relevant mailing lists on all patches.  Sending everyone the cover letter
> provides people a quick overview of the patches they didn't receive, as
> well as a starting point if they want to find those patches.  Cc'ing the
> mailing list(s) can make it even easier to find the patches.  The cover
> letter is also a good place to explain why you didn't cc everyone on all
> patches (or vice versa).
>
> Also, the cover letter should have the shortlog and overall diffstats.
> 'git format-patch --cover-letter' will do the work for you.

Thanks for your detailed reply, I's clear to me what to do now.

Zhenzhong