Date: Tue, 15 Nov 2011 15:38:58 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-current@freebsd.org Cc: mdf@freebsd.org, "K. Macy" <kmacy@freebsd.org>, Alan Cox <alc@rice.edu>, Andriy Gapon <avg@freebsd.org>, Benjamin Kaduk <kaduk@mit.edu>, Kostik Belousov <kostikbel@gmail.com>, Penta Upa <bsdboot@gmail.com> Subject: Re: vm_page_t related KBI [Was: Re: panic at vm_page_wire with FreeBSD 9.0 Beta 3] Message-ID: <201111151538.58323.jhb@freebsd.org> In-Reply-To: <20111106164204.GY50300@deviant.kiev.zoral.com.ua> References: <4EB40015.5040100@rice.edu> <CAMBSHm-Egy53818aKTpiPBA22RxqTAyQv0q8PsFUnPPDjt1cBQ@mail.gmail.com> <20111106164204.GY50300@deviant.kiev.zoral.com.ua>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sunday, November 06, 2011 11:42:04 am Kostik Belousov wrote: > On Sun, Nov 06, 2011 at 07:22:51AM -0800, mdf@freebsd.org wrote: > > On Sun, Nov 6, 2011 at 4:43 AM, Kostik Belousov <kostikbel@gmail.com> wrote: > > > Regarding the _vm_page_lock() vs. vm_page_lock_func(), the mutex.h has > > > a lot of violations in regard of the namespaces, IMO. The __* namespace > > > is reserved for the language implementation, so our freestanding program > > > (kernel) ignores the requirements of the C standard with the names like > > > __mtx_lock_spin(). Using the name _vm_page_lock() is valid, but makes > > > it not unreasonable for other developers to introduce reserved names. > > > So I decided to use the suffixes. vm_map.h locking is free of these > > > violations. > > > > I'm pretty sure that when the C standard says, "the implementation", > > they're referring to the compiler and OS it runs on. Which makes the > > FreeBSD kernel part of "the implementation", which is precisely why so > > many headers have defines that start with __ and then, if certain > > posix defines are set, also uses non-__ versions of the name. > > For libc providing parts, required by standard, you are right. > But our kernel is a freestanding program using a compiler, so in-kernel > uses of the reserved namespace is a violation. I don't buy that argument at all. We have a libc for the kernel, it's called libkern and we own that, too. We depend on using _ and __ prefixes all over the kernel and trying to change that now would be excessively gratuitous. -- John Baldwin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201111151538.58323.jhb>