[PATCH] MIPS: ralink: reduce ARCH_DMA_MINALIGN

Qingfang Deng qingfang.deng at linux.dev
Tue Apr 28 01:25:40 PDT 2026


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 at 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




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