lkml.org 
[lkml]   [2017]   [Apr]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH] of: introduce event tracepoints for dynamic device_node lifecyle
Date
Frank Rowand <frowand.list@gmail.com> writes:

> On 04/20/17 09:51, Tyrel Datwyler wrote:
>> On 04/19/2017 09:43 PM, Frank Rowand wrote:
...
>>> Which ends up being this code:
>>>
>>> of_platform_default_populate_init()
>>> of_platform_default_populate()
>>> of_platform_populate()
>>> [[ of_find_node_by_path("/") ]]
>>> [[ of_find_node_opts_by_path(path, NULL) ]]
>>> of_node_get(of_root)
>>>
>>> Note that some functions can be left out of the ARM call stack, with
>>> a return going back more than one level. The functions in the call
>>> list above that are enclosed in '[[' and ']]' were found by source
>>> inspection in those cases.
>>
>> The same thing is encountered in ppc64 stack traces. I assume it is
>> generally inlining of small functions, but I've never actually verified
>> that theory. Probably should take the time to investigate, or just ask
>> someone.
>
> Yes, inlining small functions is one reason for this.
>
> Another case I often find is that when function A calls function B calls
> function C. If the final statement of function B is 'return C()' then
> there is no need for function C to return through function B, it can
> instead return directly to function A.

It's called "Tail call optimisation", and that's more or less a good
description.

cheers

\
 
 \ /
  Last update: 2017-04-21 03:58    [W:0.101 / U:1.304 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site