Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 2 Oct 2014 11:10:20 -0400
From:      Ed Maste <emaste@freebsd.org>
To:        Konstantin Belousov <kostikbel@gmail.com>,  "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>
Subject:   Re: Kernel/Compiler bug
Message-ID:  <CAPyFy2CCViaUifsO-1xTZ8k22Y5SH5n2Hauo5nU5hyQdHVx=og@mail.gmail.com>
In-Reply-To: <20141002075537.GU26076@kib.kiev.ua>
References:  <20141001031553.GA14360@gta.com> <CAFMmRNxAYcr8eEY0SJsX3zkRadjT29-mfsGcSTmG_Yx-Hidi6w@mail.gmail.com> <20141001134044.GA57022@gta.com> <FBB9E4C3-55B9-4917-9953-F8BC9AE43619@FreeBSD.org> <542C8C75.30007@FreeBSD.org> <20141002075537.GU26076@kib.kiev.ua>

next in thread | previous in thread | raw e-mail | index | archive | help
On 2 October 2014 03:55, Konstantin Belousov <kostikbel@gmail.com> wrote:
>
> The cost of the increased size for kernel stack is significant, even
> on architectures with ample KVA.  This must not be done just because
> some non-default kernel settings cause stack overflow.  If somebody
> feels himself qualified enough to tune compiler options, it must
> understand the consequences and do other required adjustments,
> including kernel stack size tuning.

I wonder if we should have a comment in kern.pre.mk, even if it's just
an explicit notice that changing -O can have adverse effects. For
better or worse it's a fairly common desire to try changing the
kernel's -O.

Of course, kern.pre.mk is not intended to accommodate user-facing
changes. I suspect it's reasonably common for developers to grep '-O2'
in sys/conf and discover where it's getting set though.



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAPyFy2CCViaUifsO-1xTZ8k22Y5SH5n2Hauo5nU5hyQdHVx=og>