Re: [RFC] GCC support for live-patching

2018-10-24 Thread Miroslav Benes
On Tue, 23 Oct 2018, Qing Zhao wrote: > > > On Oct 23, 2018, at 4:11 AM, Miroslav Benes wrote: > >> > >> One question here, what’s the major benefit to prepare the patches > >> manually? > > > > I could almost quote what you wrote below. It is a C file, easy to review > > and maintain. You

Re: [RFC] GCC support for live-patching

2018-10-23 Thread Nicolai Stange
Hi Qing, Qing Zhao writes: > thanks a lot for your detailed explanation of the source based live patch > creation procedure. > really interesting and helpful information. > > more questions and comments below: > >>> >>> One question here, what’s the major benefit to prepare the patches >>>

Re: [RFC] GCC support for live-patching

2018-10-23 Thread Qing Zhao
> On Oct 23, 2018, at 4:11 AM, Miroslav Benes wrote: >> >> One question here, what’s the major benefit to prepare the patches >> manually? > > I could almost quote what you wrote below. It is a C file, easy to review > and maintain. You have everything "under control". It allows to impleme

Re: [RFC] GCC support for live-patching

2018-10-23 Thread Nicolai Stange
Hi, Qing Zhao writes: >> >> thanks for the proposal. The others have already expressed some of my >> worries and remarks, but I think it would be only right to write them >> again. Especially since I am part of the team responsible for >> implementation and maintenance of live patches here a

Re: [RFC] GCC support for live-patching

2018-10-23 Thread Miroslav Benes
On Mon, 22 Oct 2018, Qing Zhao wrote: > Hi, > > thanks for the comments. > > > > > thanks for the proposal. The others have already expressed some of my > > worries and remarks, but I think it would be only right to write them > > again. Especially since I am part of the team responsible for

Re: [RFC] GCC support for live-patching

2018-10-22 Thread Qing Zhao
Hi, thanks for the comments. > > thanks for the proposal. The others have already expressed some of my > worries and remarks, but I think it would be only right to write them > again. Especially since I am part of the team responsible for > implementation and maintenance of live patches here

Re: [RFC] GCC support for live-patching

2018-10-22 Thread Miroslav Benes
On Thu, 18 Oct 2018, Qing Zhao wrote: > Hi, > > After more detailed study of GCC’s IPA optimizations, further study of the > current available kernel live patching schemes and > other live-patching user’s request, I came up with the following initial > proposal in GCC to mainly support live-pa

Re: [RFC] GCC support for live-patching

2018-10-19 Thread Andi Kleen
> > Is it because you generate something manually and want to limit that > > work, > > I think that this is one of the reasons. > and as mentioned in my writeup, the targeted users of this new functionality > is for live-patching users who generate > patches by hand. Ok just means they need be

Re: [RFC] GCC support for live-patching

2018-10-19 Thread Bernhard Reutner-Fischer
On 18 October 2018 19:34:52 CEST, Qing Zhao wrote: >A. an option to control GCC's IPA optimizations to provide a safe >compilation for live-patching purpose. At the same time, provides >multiple-level control of patch code-size and run time performance >tradeoff. > >-fease-live-patching={none|