From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f49.google.com (mail-pj1-f49.google.com [209.85.216.49]) (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 0B05F1A9FBF for ; Wed, 29 Oct 2025 02:32:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.49 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761705161; cv=none; b=h8payQRZB1mEpRKXHlg9IV9c/vLKsReW7ltxtH7X5eZC0IqdsP7NXruAq2DQackp6uWQceAfUiJdVrxx8ewSPaQSKsr8UvOT8yhqLwYTNrwVpH+peN7HSTUv+fXFkNihwhin/591ZHG4fkPeOofG5L64wcPBITdz9fsoVng/7oU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761705161; c=relaxed/simple; bh=FhMdW1amZrDZOTYi1F2Y9ii4zVzoBonKSxbmPFkN9mo=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=qmBSNQfuX1d7fKBiZjA2ImCpnnMZ/3IDMjrbTXYrshWb9cb1GPXMR/5OGAsVZ1DKL6Jzc3vwkjEKx84FMYmqsSMYHn4JYAC8lIYNxGr4lKNQuBep8iJ/KTZExfszFHpz6Gr/2HT9YIrvC6amQWdvOtoK3HWEmVgZYY5uknoExhA= 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=aJEEgQAI; arc=none smtp.client-ip=209.85.216.49 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="aJEEgQAI" Received: by mail-pj1-f49.google.com with SMTP id 98e67ed59e1d1-3401314d845so3324921a91.1 for ; Tue, 28 Oct 2025 19:32:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1761705159; x=1762309959; darn=lists.linux.dev; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=JXLeKP/DtOqQuL8m7vYar3R6RP6+fCAYk9I78/ihr2U=; b=aJEEgQAI0CEHjQfnCpuXpY0fRTnnBplmjxd7oou+5mVJmFjsvkq8w25WuqgF1m3f0T 3fp5zqz5+7KzeetaInX4KGX+4l28Rm4srsnzVjeah5rD6mL2M43kvFQo+dKs4WtlHUaR HFk1oDe/vJR61hn+13RU0I/sEHJWBAQ31BlHhx46df8wZWZt0OfkdD12NIcdzilKjPHh KkJ9NQasoYppOWSzhyTdoeTleBekdKaNS9jGTyRNplL7OhrI3FtiQS0/dNVfQWucwaXZ Eayw0haqsu5n4KMw2iUbXLqLatM+bK68HD2R0aAI06xKLZcHz75Dn9SpPU340JWoM5BL iNNQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1761705159; x=1762309959; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=JXLeKP/DtOqQuL8m7vYar3R6RP6+fCAYk9I78/ihr2U=; b=KalIt5ilbDjYy9Qg7j2nY19+IEf1p9Q6646f9BfUcsh+kriepVDWH1/y6mlt0Nqud9 qqMAamgXwIIw+42H49yO/N/MimBhl+9KAv8tRSVxqYD5q973S5nkLN1i2I7yggbDf/Du lXVgHHnyb77VTekoHFljeEITFujBodNW92D/7alLSvph+EpdnybFZURqejKRPl9L4wuL 43Rkz7HmnMi/zv+mqZSJvExb4Bea2eKV+jIb9BCoGZr+ka5dxieKmIamvwv5XIuVon8k WxiBUiIACHlj+jBQeoCimQdCfkyifaCOLymdi6PC29MXgp9KbbIK07CV/k29oWyFX2RK cVUA== X-Forwarded-Encrypted: i=1; AJvYcCULYFtQ8YodfjnWpsHgHkzLUZhqEgRqCSJYKGj0MgKP8IHTmLEbVNMSqsZS3zgi1ACedxmV+A==@lists.linux.dev X-Gm-Message-State: AOJu0Yygis6EZBKGGnic6NFjtJatBYONXgGDKDCKJcn8MvETqhrOEyrw cpOpBtYp1/agb8eFY7LEjgz1FqCvBVgfBcH384EeWUBs5WvKmIqiYOUg X-Gm-Gg: ASbGncv+f9rFLQ6FHCptqbLEMcBVszGlijqRYsDMYjZUVa3uaumzA4WCrGQce/7edgt QytYNgFJniRlmTs7pV3MCOJFrI7tXybEbFcmpGSGMWCqCUPzM6ukPvtlD2Bcs8Bh04RUMg4L52N WNeXbhnr1/cs6YeOiValGKIajVxqIhs+rLqxhsf/ePaUP7wkNo17p29ycI1mWqdOeMqV9MMk0Sm ngnNe+nM4Sdg7cHUpM/FP7+s/oSKfN62hrOcaa+I5Hv5066mcl69sb15dYbsLWWpGSF3RwYFUny q0ffCUkH27d/Yio/hUAwRGMHoMDrXZa5hPSl1x4H1myp4sNOuNoeWhOfE+KOxl2Ao0819JL6rsG WFRKJIfepUPM+ZSOcBJK0C0t1dRPz8nMHsWDIVoJLC5RypUVHvwYKOBfy0vY4QKJsa2rjxmaZpJ SzzsvPufuXFwy9c3HYt3GzT7PpcNL24J9JE9JFlddqvepXJECUZZzdlwSUyg== X-Google-Smtp-Source: AGHT+IFhBNLyIOct1mE9x8NjCrvkWR0gN9M9H3c4aZoq5oEbAmNrnFsNADSTOspd44npw8jvwAKgSg== X-Received: by 2002:a17:90b:2549:b0:33f:ee05:56e1 with SMTP id 98e67ed59e1d1-3403a143527mr1244236a91.2.1761705159331; Tue, 28 Oct 2025 19:32:39 -0700 (PDT) Received: from localhost.localdomain ([47.72.128.212]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-33fed81a4afsm13649518a91.19.2025.10.28.19.32.33 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Tue, 28 Oct 2025 19:32:38 -0700 (PDT) From: Barry Song <21cnbao@gmail.com> To: Catalin Marinas , Will Deacon , Marek Szyprowski , Robin Murphy Cc: Barry Song , Ada Couprie Diaz , Ard Biesheuvel , Marc Zyngier , Anshuman Khandual , Ryan Roberts , Suren Baghdasaryan , Tangquan Zheng , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, iommu@lists.linux.dev Subject: [RFC PATCH 5/5] dma-mapping: Allow batched DMA sync operations if supported by the arch Date: Wed, 29 Oct 2025 10:31:15 +0800 Message-Id: <20251029023115.22809-6-21cnbao@gmail.com> X-Mailer: git-send-email 2.39.3 (Apple Git-146) In-Reply-To: <20251029023115.22809-1-21cnbao@gmail.com> References: <20251029023115.22809-1-21cnbao@gmail.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Barry Song This enables dma_direct_sync_sg_for_device, dma_direct_sync_sg_for_cpu, dma_direct_map_sg, and dma_direct_unmap_sg to use batched DMA sync operations when possible. This significantly improves performance on devices without hardware cache coherence. Tangquan's initial results show that batched synchronization can reduce dma_map_sg() time by 64.61% and dma_unmap_sg() time by 66.60% on an MTK phone platform (MediaTek Dimensity 9500). The tests were performed by pinning the task to CPU7 and fixing the CPU frequency at 2.6 GHz, running dma_map_sg() and dma_unmap_sg() on 10 MB buffers (10 MB / 4 KB sg entries per buffer) for 200 iterations and then averaging the results. Cc: Catalin Marinas Cc: Will Deacon Cc: Marek Szyprowski Cc: Robin Murphy Cc: Ada Couprie Diaz Cc: Ard Biesheuvel Cc: Marc Zyngier Cc: Anshuman Khandual Cc: Ryan Roberts Cc: Suren Baghdasaryan Cc: Tangquan Zheng Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: iommu@lists.linux.dev Signed-off-by: Barry Song --- kernel/dma/direct.c | 53 +++++++++++++++++++++++++--- kernel/dma/direct.h | 86 +++++++++++++++++++++++++++++++++++++++------ 2 files changed, 123 insertions(+), 16 deletions(-) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 1f9ee9759426..a0b45f84a91f 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -403,9 +403,16 @@ void dma_direct_sync_sg_for_device(struct device *dev, swiotlb_sync_single_for_device(dev, paddr, sg->length, dir); if (!dev_is_dma_coherent(dev)) - arch_sync_dma_for_device(paddr, sg->length, - dir); +#ifdef CONFIG_ARCH_WANT_BATCHED_DMA_SYNC + arch_sync_dma_for_device_batch_add(paddr, sg->length, dir); +#else + arch_sync_dma_for_device(paddr, sg->length, dir); +#endif } +#ifdef CONFIG_ARCH_WANT_BATCHED_DMA_SYNC + if (!dev_is_dma_coherent(dev)) + arch_sync_dma_batch_flush(); +#endif } #endif @@ -422,7 +429,11 @@ void dma_direct_sync_sg_for_cpu(struct device *dev, phys_addr_t paddr = dma_to_phys(dev, sg_dma_address(sg)); if (!dev_is_dma_coherent(dev)) +#ifdef CONFIG_ARCH_WANT_BATCHED_DMA_SYNC + arch_sync_dma_for_cpu_batch_add(paddr, sg->length, dir); +#else arch_sync_dma_for_cpu(paddr, sg->length, dir); +#endif swiotlb_sync_single_for_cpu(dev, paddr, sg->length, dir); @@ -430,8 +441,12 @@ void dma_direct_sync_sg_for_cpu(struct device *dev, arch_dma_mark_clean(paddr, sg->length); } - if (!dev_is_dma_coherent(dev)) + if (!dev_is_dma_coherent(dev)) { arch_sync_dma_for_cpu_all(); +#ifdef CONFIG_ARCH_WANT_BATCHED_DMA_SYNC + arch_sync_dma_batch_flush(); +#endif + } } /* @@ -443,14 +458,29 @@ void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl, { struct scatterlist *sg; int i; +#ifdef CONFIG_ARCH_WANT_BATCHED_DMA_SYNC + bool need_sync = false; +#endif for_each_sg(sgl, sg, nents, i) { - if (sg_dma_is_bus_address(sg)) + if (sg_dma_is_bus_address(sg)) { sg_dma_unmark_bus_address(sg); - else + } else { +#ifdef CONFIG_ARCH_WANT_BATCHED_DMA_SYNC + need_sync = true; + dma_direct_unmap_phys_batch_add(dev, sg->dma_address, + sg_dma_len(sg), dir, attrs); + +#else dma_direct_unmap_phys(dev, sg->dma_address, sg_dma_len(sg), dir, attrs); +#endif + } } +#ifdef CONFIG_ARCH_WANT_BATCHED_DMA_SYNC + if (need_sync && !dev_is_dma_coherent(dev)) + arch_sync_dma_batch_flush(); +#endif } #endif @@ -460,6 +490,9 @@ int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents, struct pci_p2pdma_map_state p2pdma_state = {}; struct scatterlist *sg; int i, ret; +#ifdef CONFIG_ARCH_WANT_BATCHED_DMA_SYNC + bool need_sync = false; +#endif for_each_sg(sgl, sg, nents, i) { switch (pci_p2pdma_state(&p2pdma_state, dev, sg_page(sg))) { @@ -471,8 +504,14 @@ int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents, */ break; case PCI_P2PDMA_MAP_NONE: +#ifdef CONFIG_ARCH_WANT_BATCHED_DMA_SYNC + need_sync = true; + sg->dma_address = dma_direct_map_phys_batch_add(dev, sg_phys(sg), + sg->length, dir, attrs); +#else sg->dma_address = dma_direct_map_phys(dev, sg_phys(sg), sg->length, dir, attrs); +#endif if (sg->dma_address == DMA_MAPPING_ERROR) { ret = -EIO; goto out_unmap; @@ -490,6 +529,10 @@ int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents, sg_dma_len(sg) = sg->length; } +#ifdef CONFIG_ARCH_WANT_BATCHED_DMA_SYNC + if (need_sync && !dev_is_dma_coherent(dev)) + arch_sync_dma_batch_flush(); +#endif return nents; out_unmap: diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h index da2fadf45bcd..a211bab26478 100644 --- a/kernel/dma/direct.h +++ b/kernel/dma/direct.h @@ -64,15 +64,11 @@ static inline void dma_direct_sync_single_for_device(struct device *dev, arch_sync_dma_for_device(paddr, size, dir); } -static inline void dma_direct_sync_single_for_cpu(struct device *dev, - dma_addr_t addr, size_t size, enum dma_data_direction dir) +static inline void __dma_direct_sync_single_for_cpu(struct device *dev, + phys_addr_t paddr, size_t size, enum dma_data_direction dir) { - phys_addr_t paddr = dma_to_phys(dev, addr); - - if (!dev_is_dma_coherent(dev)) { - arch_sync_dma_for_cpu(paddr, size, dir); + if (!dev_is_dma_coherent(dev)) arch_sync_dma_for_cpu_all(); - } swiotlb_sync_single_for_cpu(dev, paddr, size, dir); @@ -80,7 +76,31 @@ static inline void dma_direct_sync_single_for_cpu(struct device *dev, arch_dma_mark_clean(paddr, size); } -static inline dma_addr_t dma_direct_map_phys(struct device *dev, +#ifdef CONFIG_ARCH_WANT_BATCHED_DMA_SYNC +static inline void dma_direct_sync_single_for_cpu_batch_add(struct device *dev, + dma_addr_t addr, size_t size, enum dma_data_direction dir) +{ + phys_addr_t paddr = dma_to_phys(dev, addr); + + if (!dev_is_dma_coherent(dev)) + arch_sync_dma_for_cpu_batch_add(paddr, size, dir); + + __dma_direct_sync_single_for_cpu(dev, paddr, size, dir); +} +#endif + +static inline void dma_direct_sync_single_for_cpu(struct device *dev, + dma_addr_t addr, size_t size, enum dma_data_direction dir) +{ + phys_addr_t paddr = dma_to_phys(dev, addr); + + if (!dev_is_dma_coherent(dev)) + arch_sync_dma_for_cpu(paddr, size, dir); + + __dma_direct_sync_single_for_cpu(dev, paddr, size, dir); +} + +static inline dma_addr_t __dma_direct_map_phys(struct device *dev, phys_addr_t phys, size_t size, enum dma_data_direction dir, unsigned long attrs) { @@ -108,9 +128,6 @@ static inline dma_addr_t dma_direct_map_phys(struct device *dev, } } - if (!dev_is_dma_coherent(dev) && - !(attrs & (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_MMIO))) - arch_sync_dma_for_device(phys, size, dir); return dma_addr; err_overflow: @@ -121,6 +138,53 @@ static inline dma_addr_t dma_direct_map_phys(struct device *dev, return DMA_MAPPING_ERROR; } +#ifdef CONFIG_ARCH_WANT_BATCHED_DMA_SYNC +static inline dma_addr_t dma_direct_map_phys_batch_add(struct device *dev, + phys_addr_t phys, size_t size, enum dma_data_direction dir, + unsigned long attrs) +{ + dma_addr_t dma_addr = __dma_direct_map_phys(dev, phys, size, dir, attrs); + + if (dma_addr != DMA_MAPPING_ERROR && !dev_is_dma_coherent(dev) && + !(attrs & (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_MMIO))) + arch_sync_dma_for_device_batch_add(phys, size, dir); + + return dma_addr; +} +#endif + +static inline dma_addr_t dma_direct_map_phys(struct device *dev, + phys_addr_t phys, size_t size, enum dma_data_direction dir, + unsigned long attrs) +{ + dma_addr_t dma_addr = __dma_direct_map_phys(dev, phys, size, dir, attrs); + + if (dma_addr != DMA_MAPPING_ERROR && !dev_is_dma_coherent(dev) && + !(attrs & (DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_MMIO))) + arch_sync_dma_for_device(phys, size, dir); + + return dma_addr; +} + +#ifdef CONFIG_ARCH_WANT_BATCHED_DMA_SYNC +static inline void dma_direct_unmap_phys_batch_add(struct device *dev, dma_addr_t addr, + size_t size, enum dma_data_direction dir, unsigned long attrs) +{ + phys_addr_t phys; + + if (attrs & DMA_ATTR_MMIO) + /* nothing to do: uncached and no swiotlb */ + return; + + phys = dma_to_phys(dev, addr); + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + dma_direct_sync_single_for_cpu_batch_add(dev, addr, size, dir); + + swiotlb_tbl_unmap_single(dev, phys, size, dir, + attrs | DMA_ATTR_SKIP_CPU_SYNC); +} +#endif + static inline void dma_direct_unmap_phys(struct device *dev, dma_addr_t addr, size_t size, enum dma_data_direction dir, unsigned long attrs) { -- 2.39.3 (Apple Git-146)