Re: [Patch] mm tracepoints

[Larry Woodman]

On Fri, 2009-03-06 at 12:04 +0100, Ingo Molnar wrote:
> * Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> 
> > 
> > On Fri, 6 Mar 2009, KOSAKI Motohiro wrote:
> > 
> > > > I've implemented several mm tracepoints to track page allocation and
> > > > freeing, various types of pagefaults and unmaps, and critical page
> > > > reclamation routines.  This is useful for debugging memory allocation
> > > > issues and system performance problems under heavy memory loads:
> > > > 
> > > > # tracer: mm
> > > > #
> > > > #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
> > > > #              | |       |          |         |
> > > >          pdflush-624   [004]   184.293169: wb_kupdate:
> > > > (mm_pdflush_kupdate) count=3e48
> > > >          pdflush-624   [004]   184.293439: get_page_from_freelist:
> > > > (mm_page_allocation) pfn=447c27 zone_free=1940910
> > > >         events/6-33    [006]   184.962879: free_hot_cold_page:
> > > > (mm_page_free) pfn=44bba9
> > > >       irqbalance-8313  [001]   188.042951: unmap_vmas:
> > > > (mm_anon_userfree) mm=ffff88044a7300c0 address=7f9a2eb70000 pfn=24c29a
> > > >              cat-9122  [005]   191.141173: filemap_fault:
> > > > (mm_filemap_fault) primary fault: mm=ffff88024c9d8f40 address=3cea2dd000
> > > > pfn=44d68e
> > > >              cat-9122  [001]   191.143036: handle_mm_fault:
> > > > (mm_anon_fault) mm=ffff88024c8beb40 address=7fffbde99f94 pfn=24ce22
> > > > ...
> > > 
> > > Hi Larry,
> > > 
> > > I've started to evaluate your patch.
> > > 
> > > firstly, this patch can't apply tip/master.
> 
> yeah, would be nice to have a patch against:
> 
>   http://people.redhat.com/mingo/tip.git/README

Yeah I'll fix that, it is a moving target.
> 
> > > secondly, I don't think the address of mm_struct and pfn 
> > > help to analysis. administrator don't know the page is which 
> > > file's cache.
> > 
> > The mm_struct may not be helpful since there should be a 1 to 
> > 1 mapping between user tasks and the mm struct. Hmm, maybe 
> > not, due to threads?
> 
> Correct - so the mm ID looks useful.
> 
> > But the pfn is helpful since it is a unique identifier for 
> > what physical page was mapped.
> 
> Yeah. Nevertheless some sort of filename:offset indicator would 
> be nice too. (as an add-on)

You mean in the filemap pagefault case???

Thanks, Larry

> 
> 	Ingo

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