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From: Michael Matz <matz@suse.de>
To: Pavel Machek <pavel@ucw.cz>
Cc: Jiri Slaby <jslaby@suse.cz>,
	linux-kernel@vger.kernel.org, jirislaby@gmail.com,
	Vojtech Pavlik <vojtech@suse.cz>, Jiri Kosina <jkosina@suse.cz>,
	Udo Seidel <udoseidel@gmx.de>
Subject: Re: kgr: dealing with optimalizations? (was Re: [RFC 06/16] kgr: add Documentat)ion
Date: Fri, 9 May 2014 14:22:52 +0200 (CEST)	[thread overview]
Message-ID: <alpine.LNX.2.00.1405091419430.23942@wotan.suse.de> (raw)
In-Reply-To: <20140509093154.GA4877@xo-6d-61-c0.localdomain>

Hi,

On Fri, 9 May 2014, Pavel Machek wrote:

> Ok, one big question: you are replacing single functions, and assume 
> that's ok, right?
> 
> But ... is it ok? gcc is allowed to do optimalization on whole source 
> file (and whole source tree with LTO).  How do you prevent situation 
> where changing function foo() breaks optimalization in function bar()?

If such situation (behaviour changes with optimization) happens it's 
either compiler or a source bug, so is of no direct concern to kgraft.  
If you want to exchange an inlined function foo you of course have to take 
care of actually exchanging all functions into which foo was inlined.  
For that you need the inline tree for all kernels for which you want to 
support kgrafting.

> Is turning off inter-procedural and inter-module optimalizations needed 
> for kgraft to work?

No.


Ciao,
Michael.

  reply	other threads:[~2014-05-09 12:22 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-30 14:30 [RFC 00/16] kGraft Jiri Slaby
2014-04-30 14:30 ` [RFC 01/16] ftrace: Add function to find fentry of function Jiri Slaby
2014-04-30 14:48   ` Steven Rostedt
2014-04-30 14:58     ` Jiri Slaby
2014-04-30 14:30 ` [RFC 02/16] ftrace: Make ftrace_is_dead available globally Jiri Slaby
2014-04-30 14:30 ` [RFC 03/16] kgr: initial code Jiri Slaby
2014-04-30 14:56   ` Steven Rostedt
2014-04-30 14:57     ` Jiri Slaby
2014-05-01 20:20   ` Andi Kleen
2014-05-01 20:37     ` Jiri Kosina
2014-05-14  9:28   ` Aravinda Prasad
2014-05-14 10:12     ` Jiri Slaby
2014-05-14 10:41       ` Aravinda Prasad
2014-05-14 10:44         ` Jiri Slaby
2014-05-14 11:19           ` Aravinda Prasad
2014-05-20 11:36     ` Jiri Slaby
2014-05-21 18:28       ` Aravinda Prasad
2014-05-26  8:50       ` Jiri Kosina
2014-04-30 14:30 ` [RFC 04/16] kgr: add testing kgraft patch Jiri Slaby
2014-05-06 11:03   ` Pavel Machek
2014-05-12 12:50     ` Jiri Slaby
2014-04-30 14:30 ` [RFC 05/16] kgr: update Kconfig documentation Jiri Slaby
2014-05-03 14:32   ` Randy Dunlap
2014-04-30 14:30 ` [RFC 06/16] kgr: add Documentation Jiri Slaby
2014-05-06 11:03   ` Pavel Machek
2014-05-09  9:31     ` kgr: dealing with optimalizations? (was Re: [RFC 06/16] kgr: add Documentat)ion Pavel Machek
2014-05-09 12:22       ` Michael Matz [this message]
2014-04-30 14:30 ` [RFC 07/16] kgr: trigger the first check earlier Jiri Slaby
2014-04-30 14:30 ` [RFC 08/16] kgr: sched.h, introduce kgr_task_safe helper Jiri Slaby
2014-04-30 14:30 ` [RFC 09/16] kgr: mark task_safe in some kthreads Jiri Slaby
2014-04-30 15:49   ` Greg Kroah-Hartman
2014-04-30 16:55   ` Paul E. McKenney
2014-04-30 18:33     ` Vojtech Pavlik
2014-04-30 19:07       ` Paul E. McKenney
2014-05-01 14:24   ` Tejun Heo
2014-05-01 20:17     ` Jiri Kosina
2014-05-01 21:02       ` Tejun Heo
2014-05-01 21:09         ` Tejun Heo
2014-05-14 14:59           ` Jiri Slaby
2014-05-14 15:15             ` Vojtech Pavlik
2014-05-14 15:30               ` Paul E. McKenney
2014-05-14 16:32               ` Tejun Heo
2014-05-15  3:53                 ` Mike Galbraith
2014-05-15  4:06                   ` Tejun Heo
2014-05-15  4:46                     ` Mike Galbraith
2014-05-15  4:50                       ` Tejun Heo
2014-05-15  5:04                         ` Mike Galbraith
2014-05-15  5:09                           ` Tejun Heo
2014-05-15  5:32                             ` Mike Galbraith
2014-05-15  6:05                               ` Tejun Heo
2014-05-15  6:32                                 ` Mike Galbraith
2014-04-30 14:30 ` [RFC 10/16] kgr: kthreads support Jiri Slaby
2014-04-30 14:30 ` [RFC 11/16] kgr: handle irqs Jiri Slaby
2014-04-30 14:30 ` [RFC 12/16] kgr: add tools Jiri Slaby
2014-05-06 11:03   ` Pavel Machek
2014-04-30 14:30 ` [RFC 13/16] kgr: add MAINTAINERS entry Jiri Slaby
2014-04-30 14:30 ` [RFC 14/16] kgr: x86: refuse to build without fentry support Jiri Slaby
2014-04-30 14:30 ` [RFC 15/16] kgr: add procfs interface for per-process 'kgr_in_progress' Jiri Slaby
2014-04-30 14:30 ` [RFC 16/16] kgr: make a per-process 'in progress' flag a single bit Jiri Slaby

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