[RFC PATCH 2/2] dma-buf/udmabuf: Increase default size limit to 256MB
From: Robert Mader
Date: Sat Jul 11 2026 - 10:49:46 EST
While there does not seem to be a particularly strong reason to have a
size limit for udmabufs in the first place, raising the limit moderatly
to 256MB is enough to avoid hitting the limit in increasingly common
use-cases - notably allocating video buffers for 8K resolutions.
Signed-off-by: Robert Mader <robert.mader@xxxxxxxxxxxxx>
---
drivers/dma-buf/Kconfig | 4 ++--
drivers/dma-buf/udmabuf.c | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
index 35f0779cdc80..0e7f5dc978e2 100644
--- a/drivers/dma-buf/Kconfig
+++ b/drivers/dma-buf/Kconfig
@@ -42,9 +42,9 @@ config UDMABUF
config UDMABUF_SIZE_LIMIT_MBYTES
int "Size limit in Mega Bytes"
- default 64
+ default 256
help
- Maximum size of a udmabuf, in megabytes. Default is 64.
+ Maximum size of a udmabuf, in megabytes. Default is 256.
config DMABUF_DEBUG
bool "DMA-BUF debug checks"
diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index a83153326362..c7649a04b865 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -23,10 +23,10 @@ MODULE_PARM_DESC(list_limit, "udmabuf_create_list->count limit. Default is 1024.
#ifdef CONFIG_UDMABUF_SIZE_LIMIT_MBYTES
static int size_limit_mb = CONFIG_UDMABUF_SIZE_LIMIT_MBYTES;
#else
-static int size_limit_mb = 64;
+static int size_limit_mb = 256;
#endif
module_param(size_limit_mb, int, 0644);
-MODULE_PARM_DESC(size_limit_mb, "Max size of a dmabuf, in megabytes. Default is 64.");
+MODULE_PARM_DESC(size_limit_mb, "Max size of a dmabuf, in megabytes. Default is 256.");
struct udmabuf {
pgoff_t pagecount;
--
2.55.0