From: Christoph Hellwig <hch@lst.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>,
Linux MM <linux-mm@kvack.org>,
kvm-ppc@vger.kernel.org, nouveau@lists.freedesktop.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ira Weiny <ira.weiny@intel.com>,
Matthew Wilcox <willy@infradead.org>,
Jerome Glisse <jglisse@redhat.com>,
John Hubbard <jhubbard@nvidia.com>,
Alistair Popple <apopple@nvidia.com>,
Christoph Hellwig <hch@lst.de>, Jason Gunthorpe <jgg@nvidia.com>,
Zi Yan <ziy@nvidia.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Yang Shi <yang.shi@linux.alibaba.com>,
Paul Mackerras <paulus@ozlabs.org>,
Ben Skeggs <bskeggs@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v2] mm/hmm: make device private reference counts zero based
Date: Thu, 15 Oct 2020 09:44:23 +0200 [thread overview]
Message-ID: <20201015074423.GC14082@lst.de> (raw)
In-Reply-To: <CAPcyv4ijD+=3rje1CfSG4XKuRNfuAWOui93NQV09NmBte_gc0w@mail.gmail.com>
On Mon, Oct 12, 2020 at 02:14:07PM -0700, Dan Williams wrote:
> > ZONE_DEVICE struct pages have an extra reference count that complicates the
> > code for put_page() and several places in the kernel that need to check the
> > reference count to see that a page is not being used (gup, compaction,
> > migration, etc.). Clean up the code so the reference count doesn't need to
> > be treated specially for device private pages, leaving DAX as still being
> > a special case.
>
> Please no half-step to removing the special casing...
Agreed. I really like where the refcount changes are heading, but
I don't think this half-step is helpful.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>,
Linux MM <linux-mm@kvack.org>,
kvm-ppc@vger.kernel.org, nouveau@lists.freedesktop.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ira Weiny <ira.weiny@intel.com>,
Matthew Wilcox <willy@infradead.org>,
Jerome Glisse <jglisse@redhat.com>,
John Hubbard <jhubbard@nvidia.com>,
Alistair Popple <apopple@nvidia.com>,
Christoph Hellwig <hch@lst.de>, Jason Gunthorpe <jgg@nvidia.com>,
Zi Yan <ziy@nvidia.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Yang Shi <yang.shi@linux.alibaba.com>,
Paul Mackerras <paulus@ozlabs.org>,
Ben Skeggs <bskeggs@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v2] mm/hmm: make device private reference counts zero based
Date: Thu, 15 Oct 2020 07:44:23 +0000 [thread overview]
Message-ID: <20201015074423.GC14082@lst.de> (raw)
In-Reply-To: <CAPcyv4ijD+=3rje1CfSG4XKuRNfuAWOui93NQV09NmBte_gc0w@mail.gmail.com>
On Mon, Oct 12, 2020 at 02:14:07PM -0700, Dan Williams wrote:
> > ZONE_DEVICE struct pages have an extra reference count that complicates the
> > code for put_page() and several places in the kernel that need to check the
> > reference count to see that a page is not being used (gup, compaction,
> > migration, etc.). Clean up the code so the reference count doesn't need to
> > be treated specially for device private pages, leaving DAX as still being
> > a special case.
>
> Please no half-step to removing the special casing...
Agreed. I really like where the refcount changes are heading, but
I don't think this half-step is helpful.
next prev parent reply other threads:[~2020-10-15 7:44 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-12 17:45 [PATCH v2] mm/hmm: make device private reference counts zero based Ralph Campbell
2020-10-12 17:45 ` Ralph Campbell
2020-10-12 17:45 ` Ralph Campbell
2020-10-12 21:14 ` Dan Williams
2020-10-12 21:14 ` Dan Williams
2020-10-12 21:14 ` Dan Williams
2020-10-15 7:44 ` Christoph Hellwig [this message]
2020-10-15 7:44 ` Christoph Hellwig
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