From: Jason Gunthorpe <jgg@ziepe.ca>
To: Christoph Hellwig <hch@lst.de>
Cc: "Dan Williams" <dan.j.williams@intel.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Felix Kuehling" <Felix.Kuehling@amd.com>,
"Alex Deucher" <alexander.deucher@amd.com>,
"Christian König" <christian.koenig@amd.com>,
"Pan, Xinhui" <Xinhui.Pan@amd.com>,
"Ben Skeggs" <bskeggs@redhat.com>,
"Karol Herbst" <kherbst@redhat.com>,
"Lyude Paul" <lyude@redhat.com>,
"Alistair Popple" <apopple@nvidia.com>,
"Logan Gunthorpe" <logang@deltatee.com>,
"Ralph Campbell" <rcampbell@nvidia.com>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"amd-gfx list" <amd-gfx@lists.freedesktop.org>,
"Maling list - DRI developers" <dri-devel@lists.freedesktop.org>,
nouveau@lists.freedesktop.org,
"Linux NVDIMM" <nvdimm@lists.linux.dev>,
"Linux MM" <linux-mm@kvack.org>
Subject: Re: [PATCH 7/8] mm: remove the extra ZONE_DEVICE struct page refcount
Date: Wed, 9 Feb 2022 08:29:56 -0400 [thread overview]
Message-ID: <20220209122956.GI49147@ziepe.ca> (raw)
In-Reply-To: <20220209062345.GB7739@lst.de>
On Wed, Feb 09, 2022 at 07:23:45AM +0100, Christoph Hellwig wrote:
> On Tue, Feb 08, 2022 at 07:30:11PM -0800, Dan Williams wrote:
> > Interesting. I had expected that to really fix the refcount problem
> > that fs/dax.c would need to start taking real page references as pages
> > were added to a mapping, just like page cache.
>
> I think we should do that eventually. But I think this series that
> just attacks the device private type and extends to the device coherent
> and p2p enhacements is a good first step to stop the proliferation of
> the one off refcount and to allow to deal with the fsdax pages in another
> more focuessed series.
It is nice, but the other series are still impacted by the fsdax mess
- they still stuff pages into ptes without proper refcounts and have
to carry nonsense to dance around this problem.
I certainly would be unhappy if the amd driver, for instance, gained
the fsdax problem as well and started pushing 4k pages into PMDs.
Jason
next prev parent reply other threads:[~2022-02-09 12:29 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-07 6:32 start sorting out the ZONE_DEVICE refcount mess Christoph Hellwig
2022-02-07 6:32 ` [PATCH 1/8] mm: remove a pointless CONFIG_ZONE_DEVICE check in memremap_pages Christoph Hellwig
2022-02-07 18:08 ` Dan Williams
2022-02-07 19:22 ` Jason Gunthorpe
2022-02-08 7:17 ` Chaitanya Kulkarni
2022-02-08 8:06 ` Muchun Song
2022-02-07 6:32 ` [PATCH 2/8] mm: remove the __KERNEL__ guard from <linux/mm.h> Christoph Hellwig
2022-02-07 18:08 ` Dan Williams
2022-02-07 19:26 ` Jason Gunthorpe
2022-02-08 7:21 ` Chaitanya Kulkarni
2022-02-08 8:07 ` Muchun Song
2022-02-07 6:32 ` [PATCH 3/8] mm: remove pointless includes from <linux/hmm.h> Christoph Hellwig
2022-02-07 14:01 ` Jason Gunthorpe
2022-02-08 7:27 ` Chaitanya Kulkarni
2022-02-07 6:32 ` [PATCH 4/8] mm: move free_devmap_managed_page to memremap.c Christoph Hellwig
2022-02-07 19:06 ` Dan Williams
2022-02-07 19:27 ` Jason Gunthorpe
2022-02-08 7:34 ` Chaitanya Kulkarni
2022-02-08 8:09 ` Muchun Song
2022-02-07 6:32 ` [PATCH 5/8] mm: simplify freeing of devmap managed pages Christoph Hellwig
2022-02-07 19:34 ` Jason Gunthorpe
2022-02-07 23:42 ` Dan Williams
2022-02-08 7:50 ` Chaitanya Kulkarni
2022-02-07 6:32 ` [PATCH 6/8] mm: don't include <linux/memremap.h> in <linux/mm.h> Christoph Hellwig
2022-02-07 17:38 ` Logan Gunthorpe
2022-02-07 19:35 ` Jason Gunthorpe
2022-02-07 21:19 ` Felix Kuehling
2022-02-08 6:46 ` Christoph Hellwig
2022-02-09 17:48 ` Christoph Hellwig
2022-02-10 2:10 ` Alistair Popple
2022-02-10 6:45 ` Christoph Hellwig
2022-02-10 21:00 ` Felix Kuehling
2022-02-07 23:49 ` Dan Williams
2022-02-08 23:53 ` Dan Williams
2022-02-09 6:22 ` Christoph Hellwig
2022-02-07 6:32 ` [PATCH 7/8] mm: remove the extra ZONE_DEVICE struct page refcount Christoph Hellwig
2022-02-07 19:21 ` Jason Gunthorpe
2022-02-08 2:25 ` Ralph Campbell
2022-02-09 3:30 ` Dan Williams
2022-02-09 6:23 ` Christoph Hellwig
2022-02-09 12:29 ` Jason Gunthorpe [this message]
2022-02-09 13:53 ` Christoph Hellwig
2022-02-09 14:14 ` Jason Gunthorpe
2022-02-07 6:32 ` [PATCH 8/8] fsdax: depend on ZONE_DEVICE || FS_DAX_LIMITED Christoph Hellwig
2022-02-07 19:36 ` Jason Gunthorpe
2022-02-07 23:51 ` start sorting out the ZONE_DEVICE refcount mess Logan Gunthorpe
2022-02-08 3:03 ` Miaohe Lin
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