Date: Wed, 01 Mar 2017 08:46:53 -0700 From: Ian Lepore <ian@freebsd.org> To: Julian Elischer <julian@freebsd.org>, Warner Losh <imp@bsdimp.com>, Allan Jude <allanjude@freebsd.org> Cc: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>, Saurav Sachidanand <sauravsachidanand@gmail.com> Subject: Re: [GSoC 2017] Original proposal: Port kernel Lua to FreeBSD Message-ID: <1488383213.60166.10.camel@freebsd.org> In-Reply-To: <f221e624-1342-7548-a3f9-806a1d25b90d@freebsd.org> References: <CACKq%2BiX_V2MY9sNf-buEOO1S87dbhDv%2BPGbUEqRUVkvzz3pdvw@mail.gmail.com> <244231A2-EB18-4E58-A2B2-927F55D54950@FreeBSD.org> <CANCZdfpiiJLyLbEQnk86mfwf07JGByq5oT_1-T43iEhscEEgMg@mail.gmail.com> <f221e624-1342-7548-a3f9-806a1d25b90d@freebsd.org>
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On Wed, 2017-03-01 at 16:14 +0800, Julian Elischer wrote: > On 28/2/17 2:01 am, Warner Losh wrote: > > > > On Mon, Feb 27, 2017 at 8:26 AM, Allan Jude <allanjude@freebsd.org> > > wrote: > > > > > > On February 27, 2017 5:28:41 AM PST, Saurav Sachidanand <sauravsa > > > chidanand@gmail.com> wrote: > > > > > > > > Hello FreeBSD community, > > > > > > > > I'm > > > > Saurav Sachidanand, and I'm > > > > a CS sophomore studying in India > > > > . > > > > I have an interest in operating systems development and wish to > > > > contribute > > > > to the FreeBSD community. I'm proficient with C and have some > > > > experience in > > > > kernel programming. Hence, I'd like to propose an original > > > > project for > > > > GSoC > > > > 2017 that I feel would benefit this community. > > > > > > > > In past years, the Lua interpreter was ported to run inside the > > > > Linux > > > > and > > > > NetBSD kernel [1]. Lua was chosen because it's interpreter is > > > > very > > > > small (~240 > > > > KB) compared to that of Python or Ruby, it's MIT licensed, and > > > > is > > > > almost > > > > freestanding. A working demonstration of it is a packet > > > > filtering > > > > algorithm > > > > written entirely in kernel Lua [2]. > > > > > > > > Specifically, my proposal would be to port the following that > > > > are > > > > currently > > > > written for NetBSD: > > > > - the modified Lua VM source code with _KERNEL preprocessor > > > > directives > > > > to > > > > exclude user-space functionality like floating point, the io > > > > and os > > > > module > > > > in the standard library, etc. [3] > > > > - the kernel module device driver for /dev/lua, to which Lua > > > > scripts > > > > are > > > > fed to be executed [4], [5] > > > > - the luactl user-space program to control the Lua device and a > > > > couple > > > > of > > > > sysctl variables which serve similar purpose [6], [7] > > > > > > > > And then: > > > > - run the Lua test suite targeting whatever we support in the > > > > kernel to > > > > make sure it works [8] > > > > - and write Lua bindings to the kernel interfaces that would > > > > interest > > > > the > > > > FreeBSD community > > > > > > > > Since NetBSD and FreeBSD have similar kernel interfaces > > > > (mutexes, > > > > linked > > > > lists, device switch interface), the porting shouldn't involve > > > > too much > > > > code refactoring. Also, this would all be an experiment in that > > > > we > > > > don't > > > > fully know what the real world use cases might be, but it would > > > > attract > > > > more people to writing kernel code who otherwise wouldn't > > > > because of > > > > having > > > > to do everything in C. And it would be interesting to carry out > > > > it out > > > > in > > > > FreeBSD as well since it has a larger community than NetBSD. > > > > > > > > I humbly request anyone who is interested in this project to be > > > > my > > > > potential mentor(s) for GSoC. > > > > > > > > More slides on kernel Lua in NetBSD - [9], [10]. > > > > > > > > Thanks, > > > > Saurav > > > > > > > > [1] - http://www.netbsd.org/~lneto/dls14.pdf > > > > [2] - https://www.netbsd.org/~lneto/eurobsdcon14.pdf > > > > [3] - https://github.com/jsonn/src/tree/trunk/external/mit/lua/ > > > > dist/src > > > > [4] - > > > > https://github.com/IIJ-NetBSD/netbsd-src/tree/master/sys/module > > > > s/lua > > > > [5] - > > > > https://github.com/IIJ-NetBSD/netbsd-src/tree/master/sys/module > > > > s/luasystm > > > > [6] - https://github.com/IIJ-NetBSD/netbsd-src/tree/master/sbin > > > > /luactl > > > > [7] - http://netbsd.gw.com/cgi-bin/man-cgi?lua+4+NetBSD-current > > > > [8] - http://www.lua.org/tests/ > > > > [9] - > > > > https://www.netbsd.org/gallery/presentations/mbalmer/fosdem2012 > > > > /kernel_mode_lua.pdf > > > > [10] - https://www.lua.org/wshop13/Cormack.pdf > > > > _______________________________________________ > > > > freebsd-hackers@freebsd.org mailing list > > > > https://lists.freebsd.org/mailman/listinfo/freebsd-hackers > > > > To unsubscribe, send any mail to > > > > "freebsd-hackers-unsubscribe@freebsd.org" > > > This may be quite a nice thing to have. Another upcoming use for > > > LUA in the kernel is ZFS Channel Programs. These allow a number > > > of ZFS operations to be completed as a single atomic transaction. > > > > > > I would hope we could structure this in such a way as to not end > > > up with two copies of Lua in the kernel. > > There's also a 3/4 finished lua in the boot loader that you might > > be > > able to leverage as well.... > I'd like to see that finished. While Devin has done Heroic work with > the forth in the loader, I think it's time has come. > It' be nice to have something a little less '60s. > > > > > > > Warner I was under the impression that the "lua in bootloader" work was basically done and just needed testing, which nobody has done. I think it's all sitting in the projects/lua-bootloader branch in svn. -- Ian
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