* [PATCH] MIPS: ralink: reduce ARCH_DMA_MINALIGN
@ 2026-04-28 8:25 Qingfang Deng
2026-05-26 14:42 ` Thomas Bogendoerfer
0 siblings, 1 reply; 2+ messages in thread
From: Qingfang Deng @ 2026-04-28 8:25 UTC (permalink / raw)
To: Thomas Bogendoerfer, Qingfang Deng, linux-mips, linux-kernel
Cc: Mieczyslaw Nalewaj, Felix Fietkau, Hauke Mehrtens,
Aleksander Jan Bajkowski, Christian Marangi, Rosen Penev,
Nick Hainke, openwrt-devel
Currently, Ralink SoCs use the default ARCH_DMA_MINALIGN value of 128
bytes defined in mach-generic. This is excessive for these platforms
and leads to significant memory waste in kmalloc.
Override ARCH_DMA_MINALIGN to use L1_CACHE_BYTES, which is 16 bytes for
RT288X and 32 bytes for other Ralink SoCs.
Signed-off-by: Qingfang Deng <qingfang.deng@linux.dev>
---
arch/mips/include/asm/mach-ralink/kmalloc.h | 9 +++++++++
1 file changed, 9 insertions(+)
create mode 100644 arch/mips/include/asm/mach-ralink/kmalloc.h
diff --git a/arch/mips/include/asm/mach-ralink/kmalloc.h b/arch/mips/include/asm/mach-ralink/kmalloc.h
new file mode 100644
index 000000000000..1693209d3f37
--- /dev/null
+++ b/arch/mips/include/asm/mach-ralink/kmalloc.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_MACH_RALINK_KMALLOC_H
+#define __ASM_MACH_RALINK_KMALLOC_H
+
+#ifdef CONFIG_DMA_NONCOHERENT
+#define ARCH_DMA_MINALIGN L1_CACHE_BYTES
+#endif
+
+#endif /* __ASM_MACH_RALINK_KMALLOC_H */
--
2.43.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] MIPS: ralink: reduce ARCH_DMA_MINALIGN
2026-04-28 8:25 [PATCH] MIPS: ralink: reduce ARCH_DMA_MINALIGN Qingfang Deng
@ 2026-05-26 14:42 ` Thomas Bogendoerfer
0 siblings, 0 replies; 2+ messages in thread
From: Thomas Bogendoerfer @ 2026-05-26 14:42 UTC (permalink / raw)
To: Qingfang Deng
Cc: linux-mips, linux-kernel, Mieczyslaw Nalewaj, Felix Fietkau,
Hauke Mehrtens, Aleksander Jan Bajkowski, Christian Marangi,
Rosen Penev, Nick Hainke, openwrt-devel
On Tue, Apr 28, 2026 at 04:25:40PM +0800, Qingfang Deng wrote:
> Currently, Ralink SoCs use the default ARCH_DMA_MINALIGN value of 128
> bytes defined in mach-generic. This is excessive for these platforms
> and leads to significant memory waste in kmalloc.
>
> Override ARCH_DMA_MINALIGN to use L1_CACHE_BYTES, which is 16 bytes for
> RT288X and 32 bytes for other Ralink SoCs.
>
> Signed-off-by: Qingfang Deng <qingfang.deng@linux.dev>
> ---
> arch/mips/include/asm/mach-ralink/kmalloc.h | 9 +++++++++
> 1 file changed, 9 insertions(+)
> create mode 100644 arch/mips/include/asm/mach-ralink/kmalloc.h
applied to mips-next
Thomas.
--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]
^ permalink raw reply [flat|nested] 2+ messages in thread
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