Re: [PATCH] mm: mmap_lock: optimize mmap_lock tracepoints

[Shakeel Butt]

On Sat, Nov 23, 2024 at 05:01:57PM +0000, Matthew Wilcox wrote:
> On Fri, Nov 22, 2024 at 10:09:39PM -0800, Shakeel Butt wrote:
> >  	TP_printk(
> > -		"mm=%p memcg_path=%s write=%s",
> > -		__entry->mm,
> > -		__get_str(memcg_path),
> > +		"mm=%p memcg_id=%llu write=%s",
> > +		__entry->mm, __entry->memcg_id,
> >  		__entry->write ? "true" : "false"
> 
> Is it actually useful to print out the (hashed) pointer of the mm?
> Wouldn't the PID be more useful so you could actually associate it with
> a task?
> 

For our usecase i.e. bpftrace, we don't really care about these prints
as we can directly access the arguments like mm in bpftrace. I wonder if
others are using this hased pointer in some other way. I don't mind
chaning it but I think that would be a separate patch.