Re: [PATCH v2] x86, stacktrace: avoid recording save_stack_trace wrappers

[Josh Poimboeuf]

On Fri, Sep 29, 2017 at 11:23:35AM +0200, Vlastimil Babka wrote:
> The save_stack_trace() and save_stack_trace_tsk() wrappers of
> __save_stack_trace() add themselves to the call stack, and thus appear in the
> recorded stacktraces. This is redundant and wasteful when we have limited space
> to record the useful part of the backtrace with e.g. page_owner functionality.
> 
> Fix this by making sure __save_stack_trace() is noinline (which matches the
> current gcc decision) and bumping the skip in the wrappers
> (save_stack_trace_tsk() only when called for the current task). This is similar
> to what was done for arm in 3683f44c42e9 ("ARM: stacktrace: avoid listing
> stacktrace functions in stacktrace") and is pending for arm64.
> 
> Also make sure that __save_stack_trace_reliable() doesn't get this problem in
> the future by marking it __always_inline (which matches current gcc decision),
> per Josh Poimboeuf.
> 
> Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>

Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>

-- 
Josh