On Wed, Dec 09, 2020 at 08:43:57PM -0800, Hridya Valsaraju wrote:
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.
This information is intended to help with root-causing low-memory kills and the debugging/analysis of other memory-related issues.
It will also be used to derive DMA-BUF per-exporter stats and per-device usage stats for Android Bug reports.
Signed-off-by: Hridya Valsaraju hridya@google.com
Thanks for adding all of this, nice work!
Reviewed-by: Greg Kroah-Hartman gregkh@linuxfoundation.org