On 4/19/21 2:16 PM, Michal Hocko wrote:
On Sat 17-04-21 12:40:32, Peter Enderborg wrote:
This adds a total used dma-buf memory. Details can be found in debugfs, however it is not for everyone and not always available. dma-buf are indirect allocated by userspace. So with this value we can monitor and detect userspace applications that have problems.
The changelog would benefit from more background on why this is needed, and who is the primary consumer of that value.
I cannot really comment on the dma-buf internals but I have two remarks. Documentation/filesystems/proc.rst needs an update with the counter explanation and secondly is this information useful for OOM situations analysis? If yes then show_mem should dump the value as well.
From the implementation point of view, is there any reason why this hasn't used the existing global_node_page_state infrastructure?
I fix doc in next version. Im not sure what you expect the commit message to include.
The function of the meminfo is: (From Documentation/filesystems/proc.rst)
"Provides information about distribution and utilization of memory."
Im not the designed of dma-buf, I think global_node_page_state as a kernel internal. dma-buf is a device driver that provides a function so I might be on the outside. However I also see that it might be relevant for a OOM. It is memory that can be freed by killing userspace processes.
The show_mem thing. Should it be a separate patch?