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Tue, 29 Sep 2020 02:59:47 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 48D80A4053; Tue, 29 Sep 2020 02:59:47 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 39DE8A4040; Tue, 29 Sep 2020 02:59:44 +0000 (GMT) Received: from in.ibm.com (unknown [9.199.52.162]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Tue, 29 Sep 2020 02:59:44 +0000 (GMT) Date: Tue, 29 Sep 2020 08:29:41 +0530 From: Bharata B Rao To: Ralph Campbell Cc: linux-mm@kvack.org, kvm-ppc@vger.kernel.org, nouveau@lists.freedesktop.org, linux-kernel@vger.kernel.org, Dan Williams , Ira Weiny , Matthew Wilcox , Jerome Glisse , John Hubbard , Alistair Popple , Christoph Hellwig , Jason Gunthorpe , Zi Yan , "Kirill A . Shutemov" , Yang Shi , Paul Mackerras , Ben Skeggs , Andrew Morton Subject: Re: [PATCH 2/2] mm: remove extra ZONE_DEVICE struct page refcount Message-ID: <20200929025941.GA257792@in.ibm.com> Reply-To: bharata@linux.ibm.com References: <20200925204442.31348-1-rcampbell@nvidia.com> <20200925204442.31348-3-rcampbell@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200925204442.31348-3-rcampbell@nvidia.com> X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-09-28_25:2020-09-28,2020-09-28 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 adultscore=0 bulkscore=0 clxscore=1011 malwarescore=0 phishscore=0 suspectscore=1 priorityscore=1501 lowpriorityscore=0 impostorscore=0 spamscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009290019 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Sep 25, 2020 at 01:44:42PM -0700, Ralph Campbell 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 ZONE_DEVICE. > > Signed-off-by: Ralph Campbell > --- > arch/powerpc/kvm/book3s_hv_uvmem.c | 2 +- > drivers/gpu/drm/nouveau/nouveau_dmem.c | 2 +- > include/linux/dax.h | 2 +- > include/linux/memremap.h | 7 ++- > include/linux/mm.h | 44 -------------- > lib/test_hmm.c | 2 +- > mm/gup.c | 44 -------------- > mm/internal.h | 8 +++ > mm/memremap.c | 82 ++++++-------------------- > mm/migrate.c | 5 -- > mm/page_alloc.c | 3 + > mm/swap.c | 46 +++------------ > 12 files changed, 44 insertions(+), 203 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c > index 7705d5557239..e6ec98325fab 100644 > --- a/arch/powerpc/kvm/book3s_hv_uvmem.c > +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c > @@ -711,7 +711,7 @@ static struct page *kvmppc_uvmem_get_page(unsigned long gpa, struct kvm *kvm) > > dpage = pfn_to_page(uvmem_pfn); > dpage->zone_device_data = pvt; > - get_page(dpage); > + init_page_count(dpage); The powerpc change looks good. Passes a quick sanity test of booting/rebooting a secure guest on Power. Tested-by: Bharata B Rao Regards, Bharata.