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

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 ]