From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: [RESEND PATCH 0/7] Add FOLL_LONGTERM to GUP fast and use it
Date: Wed, 20 Feb 2019 07:19:30 -0800
Message-ID: <20190220151930.GB11695__25895.2301157237$1550676200$gmane$org@infradead.org>
References: <20190220053040.10831-1-ira.weiny@intel.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <virtualization-bounces@lists.linux-foundation.org>
Content-Disposition: inline
In-Reply-To: <20190220053040.10831-1-ira.weiny@intel.com>
List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/virtualization>,
	<mailto:virtualization-request@lists.linux-foundation.org?subject=unsubscribe>
List-Archive: <http://lists.linuxfoundation.org/pipermail/virtualization/>
List-Post: <mailto:virtualization@lists.linux-foundation.org>
List-Help: <mailto:virtualization-request@lists.linux-foundation.org?subject=help>
List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/virtualization>,
	<mailto:virtualization-request@lists.linux-foundation.org?subject=subscribe>
Sender: virtualization-bounces@lists.linux-foundation.org
Errors-To: virtualization-bounces@lists.linux-foundation.org
To: ira.weiny@intel.com
Cc: linux-fbdev@vger.kernel.org, Michal Hocko <mhocko@suse.com>, kvm@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>, James Hogan <jhogan@kernel.org>, linux-fpga@vger.kernel.org, Heiko Carstens <heiko.carstens@de.ibm.com>, dri-devel@lists.freedesktop.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, Rich Felker <dalias@libc.org>, Paul Mackerras <paulus@samba.org>, sparclinux@vger.kernel.org, ceph-devel@vger.kernel.org, devel@driverdev.osuosl.org, linux-s390@vger.kernel.org, rds-devel@oss.oracle.com, Yoshinori Sato <ysato@users.sourceforge.jp>, linux-rdma@vger.kernel.org, Jason Gunthorpe <jgg@ziepe.ca>, Ingo Molnar <mingo@redhat.com>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, xen-devel@lists.xenproject.org, devel@lists.orangefs.org, linux-media@vger.kernel.org, John Hubbard <jhubbard@nvidia.com>, kvm-ppc@vger.kernel.org, Borisla
List-Id: virtualization@lists.linuxfoundation.org

On Tue, Feb 19, 2019 at 09:30:33PM -0800, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
> 
> Resending these as I had only 1 minor comment which I believe we have covered
> in this series.  I was anticipating these going through the mm tree as they
> depend on a cleanup patch there and the IB changes are very minor.  But they
> could just as well go through the IB tree.
> 
> NOTE: This series depends on my clean up patch to remove the write parameter
> from gup_fast_permitted()[1]
> 
> HFI1, qib, and mthca, use get_user_pages_fast() due to it performance
> advantages.  These pages can be held for a significant time.  But
> get_user_pages_fast() does not protect against mapping of FS DAX pages.

This I don't get - if you do lock down long term mappings performance
of the actual get_user_pages call shouldn't matter to start with.

What do I miss?