Hi Robert, > Subject: [PATCH v2] dma-buf/udmabuf: Disable the size limit by default > > As udmabuf increasingly enjoys popularity - being used in projects like > libcamera, Gstreamer, Mesa, KWin and Weston - users more frequently > encounter cases where the current default size limit of 64MB is too low. > Examples include allocating video buffers at a 8K resolution - and even > 4K > is affected when using non-subsampled video formats and high bit > depths. > > In its current form the size limit for individual buffers does not seem to > provide any additional level of protection - such as limiting the amount > of > memory a process can pin - as the later can just allocate multiple > buffers. > If additional guardrails are desired, they would likely require some kind > accounting not limited to individual buffers. > > Therefor let's disable the size limit by default by setting it to the > maximal possible value, INT_MAX. > > Signed-off-by: Robert Mader <[email protected]> > > --- > > Changes in V2: > - Use INT_MAX instead of 0 in order to not change behavior otherwise. > > See > https://lore.kernel.org/dri-devel/20260711144814.8205-1- > [email protected]/ > for a previous attempt to make the value configurable via kconfig - and > in particular > https://lore.kernel.org/dri-devel/6764ca6f-b4d8-4baa-9d27- > [email protected]/ > for the suggestion and discussion to remove the default limit. > --- > drivers/dma-buf/udmabuf.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c > index bced421c0d65..639e93704924 100644 > --- a/drivers/dma-buf/udmabuf.c > +++ b/drivers/dma-buf/udmabuf.c > @@ -20,9 +20,9 @@ static int list_limit = 1024; > module_param(list_limit, int, 0644); > MODULE_PARM_DESC(list_limit, "udmabuf_create_list->count limit. > Default is 1024."); > > -static int size_limit_mb = 64; > +static int size_limit_mb = INT_MAX; > 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 INT_MAX.");
Acked-by: Vivek Kasireddy <[email protected]> If there are no further concerns/questions from anyone, I'll push it to drm-misc-next soon. Thanks, Vivek > > struct udmabuf { > pgoff_t pagecount; > -- > 2.55.0
