linux-kernel - Re: [PATCH v6 5/9] vsprintf: Factor out %pV handler as va

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Message-ID: <20190212130030.s22aamlnmj2lv7zg@pathway.suse.cz>
Date:   Tue, 12 Feb 2019 14:00:30 +0100
From:   Petr Mladek <pmladek@...e.com>
To:     Joe Perches <joe@...ches.com>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        "Tobin C . Harding" <me@...in.cc>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Michal Hocko <mhocko@...e.cz>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 5/9] vsprintf: Factor out %pV handler as va_format()

On Fri 2019-02-08 09:11:17, Joe Perches wrote:
> On Fri, 2019-02-08 at 16:23 +0100, Petr Mladek wrote:
> > Move the code from the long pointer() function. We are going to improve
> > error handling that will make it more complicated.
> > 
> > This patch does not change the existing behavior.
> 
> But doesn't this increase stack use?
> %pV is recursive and increasing the stack is undesired
> for this use.

%pV handler is stack sensitive because the entire vsnprintf()
machinery is called recursively. This one extra call does
not make it much worse.

Best Regards,
Petr