Re: [Patch] mm tracepoints

Steven Rostedt
2009-03-06T02:26:25Z

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.
> 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?

But the pfn is helpful since it is a unique identifier for what physical
page was mapped.

-- Steve