Date: Tue, 8 Nov 2011 20:03:22 -0500 From: Arnaud Lacombe <lacombar@gmail.com> To: Julian Elischer <julian@freebsd.org> Cc: "K. Macy" <kmacy@freebsd.org>, Alan Cox <alc@rice.edu>, Andriy Gapon <avg@freebsd.org>, Attilio Rao <attilio@freebsd.org>, freebsd-current@freebsd.org, Benjamin Kaduk <kaduk@mit.edu>, Kostik Belousov <kostikbel@gmail.com>, Penta Upa <bsdboot@gmail.com> Subject: Re: Using Instruction Pointer address in debug interfaces [Was: Re: vm_page_t related KBI [Was: Re: panic at vm_page_wire with FreeBSD 9.0 Beta 3]] Message-ID: <CACqU3MU=QXg6JDOS-y6F7j=etnTnUv5h2xAE%2BL6f8V6JfxViiA@mail.gmail.com> In-Reply-To: <4EB9C469.9070208@freebsd.org> References: <CACqU3MU_Bk%2BcObCiUa2XtM7fLkSpSDzOZqoZ=khNOR-_6ptYYQ@mail.gmail.com> <4EB9C469.9070208@freebsd.org>
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Hi, On Tue, Nov 8, 2011 at 7:08 PM, Julian Elischer <julian@freebsd.org> wrote: > On 11/8/11 10:49 AM, Arnaud Lacombe wrote: >> >> Hi, >> To avoid future complaints about the fact that I would be only "talk" >> without "action", I did implement what I suggested above. As it is >> quite a large patch-set, I will not post it directly here, however, it >> is available on github: >> >> https://github.com/lacombar/freebsd/tree/master/topic/kern-lock-debug >> >> It convert a bunch of debug interface to use the caller instruction >> pointer, as well as a proof-of-concept teaching printf(9) to convert >> IP to symbol_name+offset. >> >> It translates in a direct saving of about +250kB on i386's GENERIC, >> just in kernel text size. Even the worst case, ie LOCK_DEBUG =3D=3D 0, >> translates to a save of +80kB. >> >> Please note that this is still WIP code. > > A couple of comments. > Firstly, the idea of a printf method to print the IP as symbol+offset is = an > interesting idea > that should be followed up in its own right. > > However, (comment 2) =A0I would much rather file+line in this case. > I don't want to have the tools to decode the offset into a location in > sources. > this already exists and is called "debug symbols" - Arnaud > We have both systems in operation art work and I far prefer the latter. > >
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