DMA Engine development
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From: Alexander Kochetkov <al.kochet@gmail.com>
To: Vinod Koul <vkoul@kernel.org>,
	dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: "Nishad Saraf" <nishads@amd.com>, "Lizhi Hou" <lizhi.hou@amd.com>,
	"Jacky Huang" <ychuang3@nuvoton.com>,
	"Shan-Chun Hung" <schung@nuvoton.com>,
	"Florian Fainelli" <florian.fainelli@broadcom.com>,
	"Ray Jui" <rjui@broadcom.com>,
	"Scott Branden" <sbranden@broadcom.com>,
	"Lars-Peter Clausen" <lars@metafoo.de>,
	"Paul Cercueil" <paul@crapouillou.net>,
	"Eugeniy Paltsev" <Eugeniy.Paltsev@synopsys.com>,
	"Manivannan Sadhasivam" <mani@kernel.org>,
	"Frank Li" <Frank.Li@nxp.com>,
	"Zhou Wang" <wangzhou1@hisilicon.com>,
	"Longfang Liu" <liulongfang@huawei.com>,
	"Andy Shevchenko" <andy@kernel.org>,
	"Shawn Guo" <shawnguo@kernel.org>,
	"Sascha Hauer" <s.hauer@pengutronix.de>,
	"Pengutronix Kernel Team" <kernel@pengutronix.de>,
	"Fabio Estevam" <festevam@gmail.com>,
	"Keguang Zhang" <keguang.zhang@gmail.com>,
	"Sean Wang" <sean.wang@mediatek.com>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	"AngeloGioacchino Del Regno"
	<angelogioacchino.delregno@collabora.com>,
	"Andreas Färber" <afaerber@suse.de>,
	"Daniel Mack" <daniel@zonque.org>,
	"Haojian Zhuang" <haojian.zhuang@gmail.com>,
	"Robert Jarzmik" <robert.jarzmik@free.fr>,
	"Paul Walmsley" <paul.walmsley@sifive.com>,
	"Samuel Holland" <samuel.holland@sifive.com>,
	"Orson Zhai" <orsonzhai@gmail.com>,
	"Baolin Wang" <baolin.wang@linux.alibaba.com>,
	"Chunyan Zhang" <zhang.lyra@gmail.com>,
	"Patrice Chotard" <patrice.chotard@foss.st.com>,
	"Amélie Delaunay" <amelie.delaunay@foss.st.com>,
	"Maxime Coquelin" <mcoquelin.stm32@gmail.com>,
	"Alexandre Torgue" <alexandre.torgue@foss.st.com>,
	"Chen-Yu Tsai" <wens@csie.org>,
	"Jernej Skrabec" <jernej.skrabec@gmail.com>,
	"Laxman Dewangan" <ldewangan@nvidia.com>,
	"Jon Hunter" <jonathanh@nvidia.com>,
	"Thierry Reding" <thierry.reding@gmail.com>,
	"Peter Ujfalusi" <peter.ujfalusi@gmail.com>,
	"Kunihiko Hayashi" <hayashi.kunihiko@socionext.com>,
	"Masami Hiramatsu" <mhiramat@kernel.org>,
	"Dave Jiang" <dave.jiang@intel.com>,
	"Amit Vadhavana" <av2082000@gmail.com>,
	"Uwe Kleine-König" <u.kleine-koenig@baylibre.com>,
	"Ulf Hansson" <ulf.hansson@linaro.org>,
	"Md Sadre Alam" <quic_mdalam@quicinc.com>,
	"Alexander Kochetkov" <al.kochet@gmail.com>,
	"Casey Connolly" <casey.connolly@linaro.org>,
	"Kees Cook" <kees@kernel.org>,
	"Fenghua Yu" <fenghua.yu@intel.com>,
	"Jyothi Kumar Seerapu" <quic_jseerapu@quicinc.com>
Subject: [PATCH 0/1] dmaengine: virt-dma: convert tasklet to BH workqueue for callback invocation
Date: Fri, 13 Jun 2025 14:34:43 +0000	[thread overview]
Message-ID: <20250613143605.5748-1-al.kochet@gmail.com> (raw)

Hello!

I have Pine64 (Allwinner A64 ARMv8) board.

I've migrated from 5.4 kernel to 6.12 and noticed that DMA callback latencies
became very high. I noticed that sometimes callbacks get called from
ksoftirqd thread and in that case latencies are about 10 ms.
I found out that tasklet bacame deprecated and decided to rewrite DMA
callback code to use BH workqueue. In my case, that fixed high latencies.

My change affects a lot of drivers, but the change is trivial. I've verified
that affected drivers compile after change. But I cannot test it on all
platforms.


Alexander Kochetkov (1):
  dmaengine: virt-dma: convert tasklet to BH workqueue for callback
    invocation

 drivers/dma/amd/qdma/qdma.c                    |  1 +
 drivers/dma/arm-dma350.c                       |  1 +
 drivers/dma/bcm2835-dma.c                      |  2 +-
 drivers/dma/dma-axi-dmac.c                     |  8 ++++----
 drivers/dma/dma-jz4780.c                       |  2 +-
 drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c |  2 +-
 drivers/dma/dw-edma/dw-edma-core.c             |  2 +-
 drivers/dma/fsl-edma-common.c                  |  2 +-
 drivers/dma/fsl-edma-common.h                  |  1 +
 drivers/dma/fsl-qdma.c                         |  3 ++-
 drivers/dma/hisi_dma.c                         |  2 +-
 drivers/dma/hsu/hsu.c                          |  2 +-
 drivers/dma/idma64.c                           |  3 ++-
 drivers/dma/img-mdc-dma.c                      |  2 +-
 drivers/dma/imx-sdma.c                         |  2 +-
 drivers/dma/k3dma.c                            |  2 +-
 drivers/dma/loongson1-apb-dma.c                |  2 +-
 drivers/dma/mediatek/mtk-cqdma.c               |  2 +-
 drivers/dma/mediatek/mtk-hsdma.c               |  3 ++-
 drivers/dma/mediatek/mtk-uart-apdma.c          |  4 ++--
 drivers/dma/owl-dma.c                          |  2 +-
 drivers/dma/pxa_dma.c                          |  2 +-
 drivers/dma/qcom/bam_dma.c                     |  4 ++--
 drivers/dma/qcom/gpi.c                         |  1 +
 drivers/dma/qcom/qcom_adm.c                    |  2 +-
 drivers/dma/sa11x0-dma.c                       |  2 +-
 drivers/dma/sf-pdma/sf-pdma.c                  |  3 ++-
 drivers/dma/sprd-dma.c                         |  2 +-
 drivers/dma/st_fdma.c                          |  2 +-
 drivers/dma/stm32/stm32-dma.c                  |  1 +
 drivers/dma/stm32/stm32-dma3.c                 |  1 +
 drivers/dma/stm32/stm32-mdma.c                 |  1 +
 drivers/dma/sun6i-dma.c                        |  2 +-
 drivers/dma/tegra186-gpc-dma.c                 |  2 +-
 drivers/dma/tegra210-adma.c                    |  3 ++-
 drivers/dma/ti/edma.c                          |  2 +-
 drivers/dma/ti/k3-udma.c                       | 10 +++++-----
 drivers/dma/ti/omap-dma.c                      |  2 +-
 drivers/dma/uniphier-xdmac.c                   |  1 +
 drivers/dma/virt-dma.c                         |  6 +++---
 drivers/dma/virt-dma.h                         | 10 +++++-----
 41 files changed, 61 insertions(+), 48 deletions(-)

-- 
2.43.0


             reply	other threads:[~2025-06-13 14:36 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-13 14:34 Alexander Kochetkov [this message]
2025-06-13 14:34 ` [PATCH 1/1] dmaengine: virt-dma: convert tasklet to BH workqueue for callback invocation Alexander Kochetkov
2025-06-13 16:33   ` Andy Shevchenko
2025-06-13 18:51     ` Alexander Kochetkov
2025-06-13 20:58       ` Andy Shevchenko

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