From: Jason Gunthorpe <jgg@ziepe.ca>
To: John Hubbard <jhubbard@nvidia.com>
Cc: Ira Weiny <ira.weiny@intel.com>,
Artemy Kovalyov <artemyko@mellanox.com>,
"john.hubbard@gmail.com" <john.hubbard@gmail.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Doug Ledford <dledford@redhat.com>,
"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH v2] RDMA/umem: minor bug fix and cleanup in error handling paths
Date: Mon, 4 Mar 2019 20:53:38 -0400 [thread overview]
Message-ID: <20190305005338.GK8613@ziepe.ca> (raw)
In-Reply-To: <bef8680b-acc5-9f13-f49e-8f36f1939387@nvidia.com>
On Mon, Mar 04, 2019 at 03:11:05PM -0800, John Hubbard wrote:
> get_user_page(): increments page->_refcount by a large amount (1024)
>
> put_user_page(): decrements page->_refcount by a large amount (1024)
>
> ...and just stop doing the odd (to me) technique of incrementing once for
> each tail page. I cannot see any reason why that's actually required, as
> opposed to just "raise the page->_refcount enough to avoid losing the head
> page too soon".
I'd very much like to see this in the infiniband umem code - the extra
work and cost of touching every page in a huge page is very much
undesired.
Jason
next prev parent reply other threads:[~2019-03-05 0:53 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-02 3:27 [PATCH 0/1] RDMA/umem: minor bug fix and cleanup in error handling paths john.hubbard
2019-03-02 3:27 ` [PATCH] " john.hubbard
2019-03-02 16:03 ` kbuild test robot
2019-03-02 16:14 ` kbuild test robot
2019-03-02 20:24 ` [PATCH v2] " john.hubbard
2019-03-02 19:44 ` Ira Weiny
2019-03-03 9:52 ` Artemy Kovalyov
2019-03-03 16:55 ` Ira Weiny
2019-03-04 23:11 ` John Hubbard
2019-03-04 20:13 ` Ira Weiny
2019-03-05 20:10 ` John Hubbard
2019-03-04 23:36 ` John Hubbard
2019-03-05 0:53 ` Jason Gunthorpe [this message]
2019-03-03 22:37 ` John Hubbard
2019-03-04 6:44 ` Leon Romanovsky
2019-03-06 1:02 ` Artemy Kovalyov
2019-03-06 1:32 ` Jason Gunthorpe
2019-03-06 1:34 ` John Hubbard
2019-03-06 1:37 ` John Hubbard
2019-03-06 1:51 ` Jason Gunthorpe
2019-03-06 2:04 ` John Hubbard
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