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[172.10.233.147]) by smtp.gmail.com with ESMTPSA id 185-20020a2506c2000000b00b8f2d726471sm3464611ybg.3.2023.04.17.21.31.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Apr 2023 21:31:30 -0700 (PDT) Date: Mon, 17 Apr 2023 21:31:20 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@ripple.attlocal.net To: Luis Chamberlain cc: hughd@google.com, akpm@linux-foundation.org, willy@infradead.org, brauner@kernel.org, linux-mm@kvack.org, p.raghav@samsung.com, da.gomez@samsung.com, a.manzanares@samsung.com, dave@stgolabs.net, yosryahmed@google.com, keescook@chromium.org, patches@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 0/6] tmpfs: add the option to disable swap In-Reply-To: <20230309230545.2930737-1-mcgrof@kernel.org> Message-ID: <3382819f-4a4-8622-5642-78c03ecfb878@google.com> References: <20230309230545.2930737-1-mcgrof@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspamd-Queue-Id: 064EC40015 X-Stat-Signature: dg9fxxogqe9gwscz1icg4s17iruoqu78 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1681792291-27872 X-HE-Meta: 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 ZxtPbPfA XTwaXbm0zb6WRh27oZ11UHYHcWYJcy5ZCTH94bUAA1RsjKn7LfdH9OLDJ+fSxLF2NccFUaGDvNiIjhyKpy/SyhpwDiXXzyg4kat+edSf8gIpQLeIq6N+xzZg06EujVoTXckXMuuuUJ/zWeMDOqxi8CR6LylpizyJ9j+fWgT5T4kQSwdX1GoHXbEMDAvxU3SjPbVfyGAhLkI8OsI+mHz2YjmfD8x2zjhrzWAhbr9VyI5ZkiPSSqEancC2IVSH31Nf/Ikd0CgEoV8agOIdRxmbbLam6IINmq+2DSDAVbZGgXQzkg6gyGDQ9F6U3HDLiZRT6LSUZXGCfjICyRLAMgRU6hG869FmuLst+0t2dlWL4WVEjFjt01i4LSQ68z+oEwOq+LfFB X-Bogosity: Ham, tests=bogofilter, spamicity=0.001614, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, 9 Mar 2023, Luis Chamberlain wrote: > I'm doing this work as part of future experimentation with tmpfs and the > page cache, but given a common complaint found about tmpfs is the > innability to work without the page cache I figured this might be useful > to others. It turns out it is -- at least Christian Brauner indicates > systemd uses ramfs for a few use-cases because they don't want to use > swap and so having this option would let them move over to using tmpfs > for those small use cases, see systemd-creds(1). Thanks for your thorough work on tmpfs "noswap": seems well-received by quite a few others, that's good. I've just a few comments on later patches (I don't understand why you went into those little rearrangements at the start of shmem_writepage(), but they seem harmless so I don't object), but wanted to ask here: You say "a common complaint about tmpfs is the inability to work without the page cache". Ehh? I don't understand that at all, and have never heard such a complaint. It doesn't affect the series itself (oh, Andrew has copied that text into the first patch), but please illuminate! Thanks, Hugh