On Wed 2020-07-22 15:51:39, Josh Poimboeuf wrote: > 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@xxxxxxxxxx> > > > > > > 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 :-) Yes, it would be nice to have a cohesive documentation. But scattered pieces are better than nothing. > > > 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. IMHO, this document is useful even for newbies. They might at least get a clue about these catches. It is better than nothing. I do not want to discourage Joe from creating even better documentation. But if he does not have interest or time to work on it, I am happy even for this piece. Acked-by: Petr Mladek <pmladek@xxxxxxxx> Best Regards, Petr
