From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lf1-f53.google.com (mail-lf1-f53.google.com [209.85.167.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 471F92F39BE for ; Thu, 19 Feb 2026 20:55:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.53 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771534555; cv=none; b=OF23N5umVWER23W+PQWnyt5gcnKPxFeJZLU6sp4tncFKyWRBRV32wcnw3HqnPDELCKzbBqGNOBDdlk8o7b+FkSFGe3TzozpBxLoSe+i0wpmtlyYQmpSMo4uPHU5LABKnd0A0IGQeImbqyuABqnp2MP7MEQNt+mRA0pMi3GWK16A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771534555; c=relaxed/simple; bh=uXP1ohjFjM40tecGuIo8ml1RERwnAdFm4HtFsOJ4i1o=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=hsi78SPnJhrmQ71xUAMgpcydCDcOroocFVjMcc6N9CamND7JKRTx2s3HYfkmcijqKo7OEr7a+GuIYGrvEEpfrZWkmM+Kl7Wk7QmSUiOU5g8tG+2NZC6ApZnLg7P1u2ZVD9fzUDuQKU7yt3aJv3+yO09Va9U3kXTOrzapIpBwV9o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=BR68BVrO; arc=none smtp.client-ip=209.85.167.53 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BR68BVrO" Received: by mail-lf1-f53.google.com with SMTP id 2adb3069b0e04-59e5eaa491cso1867188e87.0 for ; Thu, 19 Feb 2026 12:55:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1771534551; x=1772139351; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=oi4HU36xhM0rM4Q26SQ6PvvbnGglLWOBTSAiQhdXIK0=; b=BR68BVrOCmQmtna07PM2tglLLcIe3jP85n4aj350Lb2MChLGKGYoQfzsEqj7ndAgtp lEgZ/xFBvv1rbzB/rkOBwLhIaQU8iFIRxGh2SGI8gREPw0TdLQQiL5HnjvF8CvqoBDBm 69sYMMKrT5TaHjpSP5cjDOpjKZG8QD2rmAgEi+rs2gp4aRtSOCwIqzB9CR5B5bB4lge/ aeBYH3zw1tEwS2TlVFYEEzXAc6wn7lNK5U1HXXA44bcRxCBTzvt5kvonK/OiL+VS6nNo WEH49ZnH1vvVAs5KpVOFTAN7TDKn8WMlEgBFxoj4zCVQfRjRBgTHQ16tu+JRVwRRDhBa uXlw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771534551; x=1772139351; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=oi4HU36xhM0rM4Q26SQ6PvvbnGglLWOBTSAiQhdXIK0=; b=nVTDSroUW4frRo2QKxdNw83WRUjbj1IF64OneOkAhJlvzBFA+EGb1zOqyY4N7WSZJ8 F0gCSfLkWuQmdB3RNg5NIDF4YBE4JDI+yUnHlR/YQv7UxpbjGQMKhVt+2Knux6ZJPxlp rizot8p00pKgBrj3j1EOJkF0IVKLrlFD5TDzOWzwSKmNYEaaa2TIBt0QWccIlZbqGa7h 1WaEBQe+Jq8+IzjJ5ZLVbvbQjwvF6AO/XlC1LzfZM4Gvw6BT9nu5kT8+w2HRxwXfY+33 QAL6CANGszOCSaavpACqVNf3nCwwH96ERbB7E15lIvk5CyHZXkT9CoVlmnJ+0yRODMnh VhjA== X-Forwarded-Encrypted: i=1; AJvYcCVNkKRWDY3osf8e18fA49ZuDfu6liIE2IQ24poChWTGodpy9sLsorHUdQooxKvpUqX+LTed9s9lOLRrWDs=@vger.kernel.org X-Gm-Message-State: AOJu0YxtLBl0/XRe73TuQtwY34uXaUZYbVpcK1YwbV83hpRncQY4hCFS Lucw7w70sJnbWmUxtd3aDBFIaYNSioXt1qsRlop1V621PX/otefKXJZr X-Gm-Gg: AZuq6aLPNgUCg79DyYqGKB9ViBgcQCWf94m8Q8E+6QG7x17ToRkMOwL4Pz3ireegaxy pm/l5cRGPJjPuXAWHCEqOHWCLovYiAGcsncJnoigFb6J2tq3btCwYQps6Z381v0sxJXZLeOZJCc S8ESlQwUPmEGKJewq+pJRcxXON7dffIOXNdGTMO+l2O2Ap3iMEAiwPiNwFW1Wwl/BH1PVeGmrIn EkitlKCin7l/NMYrR7l/7mj2ajZIVCtl7SAgq4CeXRkk6nNaUGK4OF/4X1lD7JjxXKTAHYWJDtZ CFgcMeQSuGFCwu2DiOSv+AKjCN4SSZpbLnHRmDxi4c1UBayAaSzYzqjfenv9t/59lKm0YJrgmGC IJQAGrjpS/2Hki5PEXw6+6F2zZb8pX3FEy82rpYcZBIMgwRwdtQTI8ptuS50hnXrn+fb/ErtajF 9JdbypgZd7wB5dDy54Bjo8ShNk+A06fUfU7ZFjjZmwvzioKn13WOGVEXsCN7+uehxkYWstRBMn3 WOTMs3AEXBxno+qqaYbCmpgfL1r5Cyn/0+ctRqt8fHsBQ== X-Received: by 2002:a05:6512:3a90:b0:59e:38ba:1821 with SMTP id 2adb3069b0e04-59f69c789f9mr7564403e87.48.1771534551239; Thu, 19 Feb 2026 12:55:51 -0800 (PST) Received: from buildhost.darklands.se (h-94-254-104-176.A469.priv.bahnhof.se. [94.254.104.176]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-59e5f89a356sm5443917e87.92.2026.02.19.12.55.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Feb 2026 12:55:50 -0800 (PST) From: Magnus Lindholm To: richard.henderson@linaro.org, mattst88@gmail.com, linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org, corbet@lwn.net, skhan@linuxfoundation.org, linux-doc@vger.kernel.org Cc: glaubitz@physik.fu-berlin.de, macro@orcam.me.uk, macro@redhat.com, mcree@orcon.net.nz, ink@unseen.parts, Magnus Lindholm Subject: [PATCH 0/1] alpha: enable DMA CMA support (HAVE_DMA_CONTIGUOUS) Date: Thu, 19 Feb 2026 21:53:48 +0100 Message-ID: <20260219205514.4434-1-linmag7@gmail.com> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit This series enables CONFIG_DMA_CMA support on Alpha by selecting HAVE_DMA_CONTIGUOUS and wiring up the required architecture hooks. Alpha previously relied solely on high-order page allocator allocations for coherent DMA buffers. With memory compaction now functional, CMA can be safely enabled to provide reliable physically contiguous allocations under fragmentation. Testing was performed on an Alpha UP2000+ (SMP) and a DS10 (UP) using a custom kernel module that verified the following: - Correct CMA reservation via "cma=64M" - CmaTotal/CmaFree reporting in /proc/meminfo - Successful 32 MiB dma_alloc_coherent() allocations - CmaFree reduction and recovery after free - Successful allocations under heavy memory load No allocation failures were observed. Magnus Lindholm (1): alpha: enable DMA CMA support (HAVE_DMA_CONTIGUOUS) .../io/dma-contiguous/arch-support.txt | 2 +- arch/alpha/Kconfig | 1 + arch/alpha/kernel/pci_iommu.c | 46 +++++++++++++++++++ arch/alpha/kernel/setup.c | 16 +++++++ 4 files changed, 64 insertions(+), 1 deletion(-) -- 2.52.0