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[172.10.233.147]) by smtp.gmail.com with ESMTPSA id i2sm13728602qtg.0.2021.04.26.19.23.58 (version=TLS1 cipher=ECDHE-ECDSA-AES128-SHA bits=128/128); Mon, 26 Apr 2021 19:24:00 -0700 (PDT) Date: Mon, 26 Apr 2021 19:23:57 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Axel Rasmussen cc: Alexander Viro , Andrea Arcangeli , Andrew Morton , Hugh Dickins , Jerome Glisse , Joe Perches , Lokesh Gidra , Mike Kravetz , Mike Rapoport , Peter Xu , Shaohua Li , Shuah Khan , Stephen Rothwell , Wang Qing , linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, Brian Geffon , "Dr . David Alan Gilbert" , Mina Almasry , Oliver Upton Subject: Re: [PATCH v4 04/10] userfaultfd/shmem: support minor fault registration for shmem In-Reply-To: <20210420220804.486803-5-axelrasmussen@google.com> Message-ID: References: <20210420220804.486803-1-axelrasmussen@google.com> <20210420220804.486803-5-axelrasmussen@google.com> User-Agent: Alpine 2.11 (LSU 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Stat-Signature: 9pw3t3ad3ra1comkc8hciej44mmgw1rp X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 3D1D45001533 Received-SPF: none (google.com>: No applicable sender policy available) receiver=imf01; identity=mailfrom; envelope-from=""; helo=mail-qk1-f176.google.com; client-ip=209.85.222.176 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1619490236-895256 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 Tue, 20 Apr 2021, Axel Rasmussen wrote: > This patch allows shmem-backed VMAs to be registered for minor faults. > Minor faults are appropriately relayed to userspace in the fault path, > for VMAs with the relevant flag. > > This commit doesn't hook up the UFFDIO_CONTINUE ioctl for shmem-backed > minor faults, though, so userspace doesn't yet have a way to resolve > such faults. > > Acked-by: Peter Xu > Signed-off-by: Axel Rasmussen And if this "04/10" had been numbered 03/10, I would have said Acked-by: Hugh Dickins Just read the comment above: "so userspace doesn't yet have a way to resolve such faults" - if it doesn't by this stage, we're in trouble. > --- > fs/userfaultfd.c | 6 +++--- > include/uapi/linux/userfaultfd.h | 7 ++++++- > mm/memory.c | 8 +++++--- > mm/shmem.c | 12 +++++++++++- > 4 files changed, 25 insertions(+), 8 deletions(-)