From: Joe Lawrence <joe.lawrence@redhat.com>
To: Josh Poimboeuf <jpoimboe@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 13:03:03 -0400 [thread overview]
Message-ID: <de3672ef-8779-245f-943d-3d5a4b875446@redhat.com> (raw)
In-Reply-To: <20200721230442.5v6ah7bpjx4puqva@treble>
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.
> 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. :)
> 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.
> Also the kpatch-build section can reference the patch author guide which
> we have on github.
>
Good point. I think there are a few kpatch-specific implications
(sibling call changes maybe) to consider.
-- Joe
next prev parent reply other threads:[~2020-07-22 17:03 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 [this message]
2020-07-22 20:51 ` Josh Poimboeuf
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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