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Shutemov" To: Matthew Wilcox Cc: Khalid Aziz , akpm@linux-foundation.org, longpeng2@huawei.com, arnd@arndb.de, dave.hansen@linux.intel.com, david@redhat.com, rppt@kernel.org, surenb@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC PATCH 0/6] Add support for shared PTEs across processes Message-ID: <20220125185705.wf7p2l77vggipfry@box.shutemov.name> References: <20220125114212.ks2qtncaahi6foan@box.shutemov.name> <20220125135917.ezi6itozrchsdcxg@box.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: A68F4C000C X-Stat-Signature: r95guhwrhj9mgjnxxb9y3qm6k8b5eh5z X-Rspam-User: nil Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=shutemov-name.20210112.gappssmtp.com header.s=20210112 header.b=uawUMPNc; spf=none (imf22.hostedemail.com: domain of kirill@shutemov.name has no SPF policy when checking 209.85.208.182) smtp.mailfrom=kirill@shutemov.name; dmarc=none X-HE-Tag: 1643136994-297606 X-Bogosity: Ham, tests=bogofilter, spamicity=0.065204, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Jan 25, 2022 at 02:09:47PM +0000, Matthew Wilcox wrote: > > I think zero-API approach (plus madvise() hints to tweak it) is worth > > considering. > > I think the zero-API approach actually misses out on a lot of > possibilities that the mshare() approach offers. For example, mshare() > allows you to mmap() many small files in the shared region -- you > can't do that with zeroAPI. Do you consider a use-case for many small files to be common? I would think that the main consumer of the feature to be mmap of huge files. And in this case zero enabling burden on userspace side sounds like a sweet deal. -- Kirill A. Shutemov