52 lines
1.7 KiB
Diff
52 lines
1.7 KiB
Diff
From 65033574ade97afccba074d837fd269903a83a9a Mon Sep 17 00:00:00 2001
|
|
From: Catalin Marinas <catalin.marinas@arm.com>
|
|
Date: Thu, 5 Oct 2023 16:40:30 +0100
|
|
Subject: [PATCH] arm64: swiotlb: Reduce the default size if no ZONE_DMA
|
|
bouncing needed
|
|
|
|
With CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC enabled, the arm64 kernel still
|
|
allocates the default SWIOTLB buffer (64MB) even if ZONE_DMA is disabled
|
|
or all the RAM fits into this zone. However, this potentially wastes a
|
|
non-negligible amount of memory on platforms with little RAM.
|
|
|
|
Reduce the SWIOTLB size to 1MB per 1GB of RAM if only needed for
|
|
kmalloc() buffer bouncing.
|
|
|
|
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
|
|
Suggested-by: Ross Burton <ross.burton@arm.com>
|
|
Cc: Ross Burton <ross.burton@arm.com>
|
|
Cc: Will Deacon <will@kernel.org>
|
|
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
|
|
---
|
|
arch/arm64/mm/init.c | 11 ++++++++++-
|
|
1 file changed, 10 insertions(+), 1 deletion(-)
|
|
|
|
--- a/arch/arm64/mm/init.c
|
|
+++ b/arch/arm64/mm/init.c
|
|
@@ -16,6 +16,7 @@
|
|
#include <linux/nodemask.h>
|
|
#include <linux/initrd.h>
|
|
#include <linux/gfp.h>
|
|
+#include <linux/math.h>
|
|
#include <linux/memblock.h>
|
|
#include <linux/sort.h>
|
|
#include <linux/of.h>
|
|
@@ -493,8 +494,16 @@ void __init mem_init(void)
|
|
{
|
|
bool swiotlb = max_pfn > PFN_DOWN(arm64_dma_phys_limit);
|
|
|
|
- if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC))
|
|
+ if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) && !swiotlb) {
|
|
+ /*
|
|
+ * If no bouncing needed for ZONE_DMA, reduce the swiotlb
|
|
+ * buffer for kmalloc() bouncing to 1MB per 1GB of RAM.
|
|
+ */
|
|
+ unsigned long size =
|
|
+ DIV_ROUND_UP(memblock_phys_mem_size(), 1024);
|
|
+ swiotlb_adjust_size(min(swiotlb_size_or_default(), size));
|
|
swiotlb = true;
|
|
+ }
|
|
|
|
swiotlb_init(swiotlb, SWIOTLB_VERBOSE);
|
|
|