Re: revamp vmem_altmap / dev_pagemap handling V3

From: Michal Hocko <mhocko@kernel.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: "Christoph Hellwig" <hch@lst.de>,
	linux-nvdimm@lists.01.org, "X86 ML" <x86@kernel.org>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"Linux MM" <linux-mm@kvack.org>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: revamp vmem_altmap / dev_pagemap handling V3
Date: Mon, 8 Jan 2018 22:50:59 +0100	[thread overview]
Message-ID: <20180108215059.GB1732@dhcp22.suse.cz> (raw)
In-Reply-To: <CAPcyv4ipGv613NgJZ8HEWTV4DrDxRdrMwD=8odZevvBQaQwuCA@mail.gmail.com>

On Mon 08-01-18 13:27:13, Dan Williams wrote:
> On Mon, Jan 8, 2018 at 12:25 PM, Michal Hocko <mhocko@kernel.org> wrote:
> > On Mon 08-01-18 11:44:02, Dan Williams wrote:
> >> On Mon, Jan 8, 2018 at 3:26 AM, Christoph Hellwig <hch@lst.de> wrote:
> >> > Any chance to get this fully reviewed and picked up before the
> >> > end of the merge window?
> >>
> >> I'm fine carrying these through the nvdimm tree, but I'd need an ack
> >> from the mm folks for all the code touches related to arch_add_memory.
> >
> > I am sorry to be slow here but I am out of time right now - yeah having
> > a lot of fun kaiser time. I didn't get to look at these patches at all
> > yet but the changelog suggests that you want to remove vmem_altmap.
> > I've had plans to (ab)use this for self hosted struct pages for memory
> > hotplug http://lkml.kernel.org/r/20170801124111.28881-1-mhocko@kernel.org
> > That work is stalled though because it is buggy and I was too busy to
> > finish that work. Anyway, if you believe that removing vmem_altmap is a
> > good step in general I will find another way. I wasn't really happy how
> > the whole thing is grafted to the memory hotplug and (ab)used it only
> > because it was handy and ready for reuse.
> 
> You misread, these are keeping vmem_altmap and cleaning up the usage
> to pass the vmem_altmap pointer through all paths rather than the
> tricky radix lookup we were doing previously.

Good to hear. I really didn't get further than reading through email
subjects and for some reason I misread those.

> > Anyway if you need a review of mm parts from me, you will have to wait
> > some more. If this requires some priority then go ahead and merge
> > it. Times are just too crazy right now.
> 
> Since you were planning on reusing vmem_altmap I think these patches
> make your job easier. I don't see the risk in merging these, we've
> squeezed out a few bugs and all the nvdimm unit tests are passing.

Good, then really do not wait for me if this aims to get merged soon.

> > Sorry about that.
> 
> No worries, quite a few of us are in that same boat.

Yeah the boat is quite large I suspect...

-- 
Michal Hocko
SUSE Labs

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>