From: "Weiny, Ira" <ira.weiny@intel.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Daniel Borkmann <daniel@iogearbox.net>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"Marciniszyn, Mike" <mike.marciniszyn@intel.com>,
"Dalessandro, Dennis" <dennis.dalessandro@intel.com>,
Doug Ledford <dledford@redhat.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
"Williams, Dan J" <dan.j.williams@intel.com>
Subject: RE: [PATCH 0/3] Add gup fast + longterm and use it in HFI1
Date: Mon, 11 Feb 2019 22:40:02 +0000 [thread overview]
Message-ID: <2807E5FD2F6FDA4886F6618EAC48510E79BCF37B@CRSMSX101.amr.corp.intel.com> (raw)
In-Reply-To: <20190211222208.GJ24692@ziepe.ca>
> On Mon, Feb 11, 2019 at 01:42:57PM -0800, Ira Weiny wrote:
> > On Mon, Feb 11, 2019 at 01:47:10PM -0700, Jason Gunthorpe wrote:
> > > On Mon, Feb 11, 2019 at 12:34:17PM -0800, Davidlohr Bueso wrote:
> > > > On Mon, 11 Feb 2019, ira.weiny@intel.com wrote:
> > > > > Ira Weiny (3):
> > > > > mm/gup: Change "write" parameter to flags
> > > > > mm/gup: Introduce get_user_pages_fast_longterm()
> > > > > IB/HFI1: Use new get_user_pages_fast_longterm()
> > > >
> > > > Out of curiosity, are you planning on having all rdma drivers use
> > > > get_user_pages_fast_longterm()? Ie:
> > > >
> > > > hw/mthca/mthca_memfree.c: ret = get_user_pages_fast(uaddr &
> PAGE_MASK, 1, FOLL_WRITE, pages);
> > >
> > > This one is certainly a mistake - this should be done with a umem.
> >
> > It looks like this is mapping a page allocated by user space for a
> > doorbell?!?!
>
> Many drivers do this, the 'doorbell' is a PCI -> CPU thing of some sort
My surprise is why does _userspace_ allocate this memory?
>
> > This does not seem to be allocating memory regions. Jason, do you
> > want a patch to just convert these calls and consider it legacy code?
>
> It needs to use umem like all the other drivers on this path.
> Otherwise it doesn't get the page pinning logic right
Not sure what you mean regarding the pinning logic?
>
> There is also something else rotten with these longterm callsites, they seem
> to have very different ideas how to handle RLIMIT_MEMLOCK.
>
> ie vfio doesn't even touch pinned_vm.. and rdma is applying
> RLIMIT_MEMLOCK to mm->pinned_vm, while vfio is using locked_vm.. No
> idea which is right, but they should be the same, and this pattern should
> probably be in core code someplace.
Neither do I. But AFAIK pinned_vm is a subset of locked_vm.
So should we be accounting both of the counters?
Ira
next prev parent reply other threads:[~2019-02-11 22:40 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-11 20:16 [PATCH 0/3] Add gup fast + longterm and use it in HFI1 ira.weiny
2019-02-11 20:16 ` [PATCH 1/3] mm/gup: Change "write" parameter to flags ira.weiny
2019-02-11 20:16 ` [PATCH 2/3] mm/gup: Introduce get_user_pages_fast_longterm() ira.weiny
2019-02-11 20:39 ` Jason Gunthorpe
2019-02-11 21:13 ` John Hubbard
2019-02-11 21:26 ` Ira Weiny
2019-02-11 21:39 ` John Hubbard
2019-02-11 21:45 ` Dan Williams
2019-02-11 21:52 ` Ira Weiny
2019-02-11 22:01 ` John Hubbard
2019-02-11 22:06 ` Jason Gunthorpe
2019-02-11 22:55 ` Dan Williams
2019-02-11 23:04 ` Weiny, Ira
2019-02-11 23:25 ` Jason Gunthorpe
2019-02-12 0:08 ` Ira Weiny
2019-02-11 20:16 ` [PATCH 3/3] IB/HFI1: Use new get_user_pages_fast_longterm() ira.weiny
2019-02-11 20:34 ` [PATCH 0/3] Add gup fast + longterm and use it in HFI1 Davidlohr Bueso
2019-02-11 20:47 ` Jason Gunthorpe
2019-02-11 21:42 ` Ira Weiny
2019-02-11 22:22 ` Jason Gunthorpe
2019-02-11 22:40 ` Weiny, Ira [this message]
2019-02-11 22:50 ` Jason Gunthorpe
2019-02-11 21:29 ` Ira Weiny
2019-02-11 20:40 ` Jason Gunthorpe
2019-02-11 21:14 ` Weiny, Ira
2019-02-11 22:23 ` Jason Gunthorpe
2019-02-13 23:04 ` [PATCH V2 0/7] Add FOLL_LONGTERM to GUP fast and use it ira.weiny
2019-02-13 23:04 ` [PATCH V2 1/7] mm/gup: Replace get_user_pages_longterm() with FOLL_LONGTERM ira.weiny
2019-02-13 23:04 ` [PATCH V2 2/7] mm/gup: Change write parameter to flags in fast walk ira.weiny
2019-02-13 23:04 ` [PATCH V2 3/7] mm/gup: Change GUP fast to use flags rather than a write 'bool' ira.weiny
2019-02-13 23:04 ` [PATCH V2 4/7] mm/gup: Add FOLL_LONGTERM capability to GUP fast ira.weiny
2019-02-13 23:04 ` [PATCH V2 5/7] IB/hfi1: Use the new FOLL_LONGTERM flag to get_user_pages_fast() ira.weiny
2019-02-13 23:04 ` [PATCH V2 6/7] IB/qib: " ira.weiny
2019-02-13 23:04 ` [PATCH V2 7/7] IB/mthca: " ira.weiny
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