Re: [PATCH] dmabuf: Add the capability to expose DMA-BUF stats in sysfs

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Dec 10, 2020 at 10:58:50AM +0100, Christian König wrote:
> In general a good idea, but I have a few concern/comments here.
> 
> Am 10.12.20 um 05:43 schrieb Hridya Valsaraju:
> > This patch allows statistics to be enabled for each DMA-BUF in
> > sysfs by enabling the config CONFIG_DMABUF_SYSFS_STATS.
> > 
> > The following stats will be exposed by the interface:
> > 
> > /sys/kernel/dmabuf/<inode_number>/exporter_name
> > /sys/kernel/dmabuf/<inode_number>/size
> > /sys/kernel/dmabuf/<inode_number>/dev_map_info
> > 
> > The inode_number is unique for each DMA-BUF and was added earlier [1]
> > in order to allow userspace to track DMA-BUF usage across different
> > processes.
> > 
> > Currently, this information is exposed in
> > /sys/kernel/debug/dma_buf/bufinfo.
> > However, since debugfs is considered unsafe to be mounted in production,
> > it is being duplicated in sysfs.
> 
> Mhm, this makes it part of the UAPI. What is the justification for this?
> 
> In other words do we really need those debug information in a production
> environment?

Production environments seem to want to know who is using up memory :)