Re: [RFC 5/7] LTTng instrumentation mm

Dave Hansen
2007-11-15T21:07:08Z

> On Tue, 2007-11-13 at 14:33 -0500, Mathieu Desnoyers wrote:
> linux-2.6-lttng/mm/page_io.c 2007-11-13 09:49:35.000000000 -0500
> @@ -114,6 +114,7 @@ int swap_writepage(struct page *page, st
> rw |= (1 << BIO_RW_SYNC);
> count_vm_event(PSWPOUT);
> set_page_writeback(page);
> + trace_mark(mm_swap_out, "address %p", page_address(page));
> unlock_page(page);
> submit_bio(rw, bio);
> out:

I'm not sure all this page_address() stuff makes any sense on highmem
systems. How about page_to_pfn()?

I also have to wonder if you should be hooking into count_vm_event() and
using those. Could you give a high-level overview of exactly why you
need these hooks, and perhaps what you expect from future people adding
things to the VM?

-- Dave