Re: [PATCH v5 0/9] mmu notifier provide context informations

From: Jerome Glisse <jglisse@redhat.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: "Linux MM" <linux-mm@kvack.org>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"Christian König" <christian.koenig@amd.com>,
	"Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	"Rodrigo Vivi" <rodrigo.vivi@intel.com>,
	"Jan Kara" <jack@suse.cz>,
	"Andrea Arcangeli" <aarcange@redhat.com>,
	"Peter Xu" <peterx@redhat.com>,
	"Felix Kuehling" <Felix.Kuehling@amd.com>,
	"Jason Gunthorpe" <jgg@mellanox.com>,
	"Ross Zwisler" <zwisler@kernel.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Michal Hocko" <mhocko@kernel.org>,
	"Ralph Campbell" <rcampbell@nvidia.com>,
	"John Hubbard" <jhubbard@nvidia.com>,
	"KVM list" <kvm@vger.kernel.org>,
	"Maling list - DRI developers" <dri-devel@lists.freedesktop.org>,
	linux-rdma <linux-rdma@vger.kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	"Arnd Bergmann" <arnd@arndb.de>
Subject: Re: [PATCH v5 0/9] mmu notifier provide context informations
Date: Tue, 19 Feb 2019 15:57:52 -0500	[thread overview]
Message-ID: <20190219205751.GD3959@redhat.com> (raw)
In-Reply-To: <CAPcyv4gUFSA6u77dGA6XxO41217zQ27DNteiHRG515Gtm_uGgg@mail.gmail.com>

On Tue, Feb 19, 2019 at 12:40:37PM -0800, Dan Williams wrote:
> On Tue, Feb 19, 2019 at 12:30 PM Jerome Glisse <jglisse@redhat.com> wrote:
> >
> > On Tue, Feb 19, 2019 at 12:15:55PM -0800, Dan Williams wrote:
> > > On Tue, Feb 19, 2019 at 12:04 PM <jglisse@redhat.com> wrote:
> > > >
> > > > From: Jérôme Glisse <jglisse@redhat.com>
> > > >
> > > > Since last version [4] i added the extra bits needed for the change_pte
> > > > optimization (which is a KSM thing). Here i am not posting users of
> > > > this, they will be posted to the appropriate sub-systems (KVM, GPU,
> > > > RDMA, ...) once this serie get upstream. If you want to look at users
> > > > of this see [5] [6]. If this gets in 5.1 then i will be submitting
> > > > those users for 5.2 (including KVM if KVM folks feel comfortable with
> > > > it).
> > >
> > > The users look small and straightforward. Why not await acks and
> > > reviewed-by's for the users like a typical upstream submission and
> > > merge them together? Is all of the functionality of this
> > > infrastructure consumed by the proposed users? Last time I checked it
> > > was only a subset.
> >
> > Yes pretty much all is use, the unuse case is SOFT_DIRTY and CLEAR
> > vs UNMAP. Both of which i intend to use. The RDMA folks already ack
> > the patches IIRC, so did radeon and amdgpu. I believe the i915 folks
> > were ok with it too. I do not want to merge things through Andrew
> > for all of this we discussed that in the past, merge mm bits through
> > Andrew in one release and bits that use things in the next release.
> 
> Ok, I was trying to find the links to the acks on the mailing list,
> those references would address my concerns. I see no reason to rush
> SOFT_DIRTY and CLEAR ahead of the upstream user.

I intend to post user for those in next couple weeks for 5.2 HMM bits.
So user for this (CLEAR/UNMAP/SOFTDIRTY) will definitly materialize in
time for 5.2.

ACKS AMD/RADEON https://lkml.org/lkml/2019/2/1/395
ACKS RDMA https://lkml.org/lkml/2018/12/6/1473

For KVM Andrea Arcangeli seems to like the whole idea to restore the
change_pte optimization but i have not got ACK from Radim or Paolo,
however given the small performance improvement figure i get with it
i do not see while they would not ACK.

https://lkml.org/lkml/2019/2/18/1530

Cheers,
Jérôme