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Tue, 09 Sep 2025 07:16:50 -0700 (PDT) Received: from smtpclient.apple ([39.144.103.165]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-24c9c2b12f9sm171757705ad.101.2025.09.09.07.16.47 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 09 Sep 2025 07:16:50 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3826.700.81\)) Subject: Re: [PATCH] mm: shmem: fix too little space for tmpfs only fallback 4KB From: Vernon Yang In-Reply-To: <20250908162220.480d7014cc6c6ad2e14748c5@linux-foundation.org> Date: Tue, 9 Sep 2025 22:16:34 +0800 Cc: Vernon Yang , hughd@google.com, baolin.wang@linux.alibaba.com, da.gomez@samsung.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vernon Yang Content-Transfer-Encoding: 7bit Message-Id: <441CA7B5-4D1C-4334-AC1A-2CDA87530478@gmail.com> References: <20250908123128.900254-1-vernon2gm@gmail.com> <20250908162220.480d7014cc6c6ad2e14748c5@linux-foundation.org> To: Andrew Morton X-Mailer: Apple Mail (2.3826.700.81) X-Stat-Signature: 618pzhyi94nfn3kdckqrik7f5fg95mba X-Rspam-User: X-Rspamd-Queue-Id: 4583B80015 X-Rspamd-Server: rspam04 X-HE-Tag: 1757427412-130824 X-HE-Meta: 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 P6ImdEbq A2Q5Yu0uj0kg2yhEgyBlM5TdLt0K3GiHUYLyjOi6BdCk8SotLZG0LtDnAe6eWYIVx4LxIwJ6xem+1WfG4T6KjS3/CpXUftIqXGuuJ/Q/P4dtHpB+vuLKJLzpd1ZYvhK8JSIkuDvhUWjVmT7UXvcTjUNnLoKT7kg2+bYZBHdERVFZKemoVEWiotZ9CzDVXBEH+9EwBRHOS6RhdhXzh1BaroemymcBYP+BZW+6auTWrKJjqDAdr83a43wq4TCi6sGMA+wB8arzCs2gHJ+SsmSp5LHs1lI7DXN9TNSUBuesNAMjxydtxvQ05JQnpk4KWDZPbHDfHyIlNhcGxlMAN12eva90WyPUBJTh4C+msi+SF2nMQmhnsEJz27WHfBwidBgLmuuLrB3TwoYOv6pqa+N8ygw2Jq4uWdjG+HLYDuuzyOrU+Gk+KdRuisj98M0oDFmIcg5B2IG+2W4zUtXsZ3NWFLgGdg3HLff0aL7sZjRLzsulIvZIH7WmEs2FcaxrJuEIuXxeLo8uJlv3jFGB10Qe5Y06npw== 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: List-Subscribe: List-Unsubscribe: > On Sep 9, 2025, at 07:22, Andrew Morton wrote: > > On Mon, 8 Sep 2025 20:31:28 +0800 Vernon Yang wrote: > >> From: Vernon Yang >> >> When the system memory is sufficient, allocating memory is always >> successful, but when tmpfs size is low (e.g. 1MB), it falls back >> directly from 2MB to 4KB, and other small granularity (8KB ~ 1024KB) >> will not be tried. >> >> Therefore add check whether the remaining space of tmpfs is sufficient >> for allocation. If there is too little space left, try smaller large >> folio. > > Thanks. > > What are the effects of this change? I'm assuming it's an > *improvement*, rather than a fix for some misbehavior? > When we use tmpfs and the tmpfs space is getting smaller and smaller (e.g. less than 2MB), it can still allocate 8KB~1MB large folio. Thank you for your feedback.