From: Joe Perches <joe@perches.com>
To: Steven Rostedt <rostedt@goodmis.org>, Petr Mladek <pmladek@suse.com>
Cc: Yue Haibing <yuehaibing@huawei.com>,
sergey.senozhatsky@gmail.com, andriy.shevchenko@linux.intel.com,
geert+renesas@glider.be, me@tobin.cc,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH -next] lib/vsprintf: Make function pointer_string static
Date: Mon, 29 Apr 2019 09:42:30 -0700 [thread overview]
Message-ID: <3078981761ff2a37354221eb79a1c24e43c30896.camel@perches.com> (raw)
In-Reply-To: <20190429103925.6233e45f@gandalf.local.home>
On Mon, 2019-04-29 at 10:39 -0400, Steven Rostedt wrote:
> [ added Joe ]
> > Good question. I have just double checked it. And pointer_string() with
> > "noinline_for_stack" does not make any difference in the stack
> > usage here.
> >
> > I actually played with this before:
> >
> > "noinline_for_stack" is a black magic added by
> > the commit cf3b429b03e827c7180 ("vsprintf.c: use noinline_for_stack").
>
> From what I understand, "noinline_for_stack" is just noinline and the
> "for_stack" part is just to document that the noinline is used for
> stack purposes. If the compiler doesn't inline the function without the
> noinline, then it wont make any difference.
>
> The point was to not inline the function because it can be used in
> stack critical areas, and that it's better to do the call than to
> increase the stack.
It was added because of %pV is recursive and recursive
functions can eat
a lot of stack.
Using noinline_for_stack was just a bit more self-documenting.
I do still think it's a useful notation.
next prev parent reply other threads:[~2019-04-29 16:42 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-26 16:46 [PATCH -next] lib/vsprintf: Make function pointer_string static Yue Haibing
2019-04-26 17:02 ` Steven Rostedt
2019-04-29 11:08 ` Petr Mladek
2019-04-29 13:13 ` Steven Rostedt
2019-04-29 14:30 ` Petr Mladek
2019-04-29 14:39 ` Steven Rostedt
2019-04-29 16:42 ` Joe Perches [this message]
2019-04-30 8:42 ` Petr Mladek
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