From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Joe Lawrence <joe.lawrence@redhat.com>
Cc: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] docs/livepatch: Add new compiler considerations doc
Date: Wed, 22 Jul 2020 15:51:39 -0500 [thread overview]
Message-ID: <20200722205139.hwbej2atk2ejq27n@treble> (raw)
In-Reply-To: <de3672ef-8779-245f-943d-3d5a4b875446@redhat.com>
On Wed, Jul 22, 2020 at 01:03:03PM -0400, Joe Lawrence wrote:
> On 7/21/20 7:04 PM, Josh Poimboeuf wrote:
> > On Tue, Jul 21, 2020 at 12:14:06PM -0400, Joe Lawrence wrote:
> > > Compiler optimizations can have serious implications on livepatching.
> > > Create a document that outlines common optimization patterns and safe
> > > ways to livepatch them.
> > >
> > > Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
> >
> > There's a lot of good info here, but I wonder if it should be
> > reorganized a bit and instead called "how to create a livepatch module",
> > because that's really the point of it all.
> >
>
> That would be nice. Would you consider a stand-alone compiler-optimizations
> doc an incremental step towards that end? Note that the other files
> (callbacks, shadow-vars, system-state) in their current form might be as
> confusing to the newbie.
It's an incremental step towards _something_. Whether that's a cohesive
patch creation guide, or just a growing hodgepodge of random documents,
it may be too early to say :-)
> > I'm thinking a newcomer reading this might be lost. It's not
> > necessarily clear that there are currently two completely different
> > approaches to creating a livepatch module, each with their own quirks
> > and benefits/drawbacks. There is one mention of a "source-based
> > livepatch author" but no explanation of what that means.
> >
>
> Yes, the initial draft was light on source-based patching since I only
> really tinker with it for samples/kselftests. The doc was the result of an
> experienced livepatch developer and Sunday afternoon w/the compiler. I'm
> sure it reads as such. :)
Are experienced livepatch developers the intended audience? If so I
question what value this document has in its current form. Presumably
experienced livepatch developers would already know this stuff.
> > Maybe it could begin with an overview of the two approaches, and then
> > delve more into the details of each approach, and then delve even more
> > into the gory details about compiler optimizations.
> >
>
> Up until now, the livepatch documentation has danced around the particular
> creation method and only described the API in abstract. If a compiler
> considerations doc needs to have that complete context then I'd suggest we
> reorganize the entire lot as a prerequisite.
I wouldn't say it *needs* to have that context. But it would be a lot
more useful with it. As you pointed out, the existing documents do need
to be reorganized into a more cohesive whole.
--
Josh
next prev parent reply other threads:[~2020-07-22 20:51 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-21 16:14 [PATCH 0/2] livepatch: Add compiler optimization disclaimer/docs Joe Lawrence
2020-07-21 16:14 ` [PATCH 1/2] docs/livepatch: Add new compiler considerations doc Joe Lawrence
2020-07-21 23:04 ` Josh Poimboeuf
2020-07-22 17:03 ` Joe Lawrence
2020-07-22 20:51 ` Josh Poimboeuf [this message]
2020-08-06 12:03 ` Petr Mladek
2020-08-10 19:46 ` refactoring livepatch documentation was " Joe Lawrence
2020-09-01 17:12 ` Josh Poimboeuf
2020-09-02 14:00 ` Miroslav Benes
2020-09-02 13:45 ` Miroslav Benes
2020-07-21 16:14 ` [PATCH 2/2] samples/livepatch: Add README.rst disclaimer Joe Lawrence
2020-08-06 12:07 ` Petr Mladek
2020-09-02 13:46 ` Miroslav Benes
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