Messages in this thread | | | From | David Howells <> | Subject | Re: [RFC] Refactor kenter/kleave/kdebug macros | Date | Mon, 18 May 2015 16:20:36 +0100 |
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Leon Romanovsky <leon@leon.nu> wrote:
> >> Additionally, It looks like the output of these macros can be viewed by > >> ftrace mechanism. > > > > *blink* It can? > I was under strong impression that "function" and "function_graph" > tracers will give similar kenter/kleave information. Do I miss > anything important, except the difference in output format? > > > > >> Maybe we should delete them from mm/nommu.c as was pointed by Joe? > > > > Why? > If ftrace is sufficient to get the debug information, there will no > need to duplicate it.
It isn't sufficient. It doesn't store the parameters or the return value, it doesn't distinguish the return path in a function when there's more than one, eg.:
kleave(" = %d [val]", ret);
vs:
kleave(" = %lx", result);
in do_mmap_pgoff() and it doesn't permit you to retrieve data from where the argument pointers that you don't have pointed to, eg.:
kenter("%p{%d}", region, region->vm_usage);
David
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