On 02/09/2016 10:43 AM, Tom Rini wrote:
On Tue, Feb 09, 2016 at 10:26:14AM -0700, Stephen Warren wrote:
On 02/09/2016 10:01 AM, Tom Rini wrote:
On Tue, Feb 09, 2016 at 08:11:15AM -0800, James Chargin wrote:
On 02/08/2016 05:32 PM, Stephen Warren wrote:
From: Stephen Warren swarren@nvidia.com
If BUILD_TAG is part of KBUILD_CFLAGS, then any time the value changes, all files get rebuilt. In a continuous integration environment, the value will change every build. This wastes time assuming that incremental builds would otherwise occur.
To solve this, remove BUILD_TAG from KBUILD_FLAGS and add it to the end of "local version".
This has other advantages too:
- The special case for BUILD_TAG in display_options.c can be removed.
- The version printed by the "version" command exactly matches what is printed at boot.
Old sign-on message: U-Boot 2016.03-rc1-00044-g4085db5e767b (Feb ...), Build: bar-bas
New sign-on message: U-Boot 2016.03-rc1-00044-g4085db5e767b-bar-baz (Feb ...)
I would urge this not be done. The display of the BUILD_TAG on startup is pretty useful in my environment. It's been there for a long time and some of my users have grown used to it.
Of all the parts of the sign-on message, I'd rather the git hash go away than the BUILD_TAG. None of my users really care about the level of detail of the git hash and won't spend the time required to use this hash to determine if they have the version they want. (Some don't have a repo clone, and don't care to, and so can't easily make the correspondence even if they wanted to).
Yeah, I think this is too widely used of a thing to change. FWIW, I really like githashes since it means you can see if $random-binary is something you have in $vendor-tree or not. So I think in this case, NAK on the patch and maybe need to poke Travis-CI on how to or not to tag things?
Do you mean you think people currently rely upon the ", Build: xxx" format in the sign-on message, and the "version" command /not/ printing that information?
I mean that the places we construct strings like this are likely relied upon by people, yes.
If so, I'll go back to trying to work out how to get Kbuild to transfer the environment variable into a CONFIG_XXX option so that modifying it only causes a rebuild of the one file that uses the value.
A quick peak and I think that: (a) LOCALVERSION needs a little love somewhere to ensure that it in fact does not exceed 64 characters (and pushing upstream to the kernel anything relevant here) (b) Yes, adjusting BUILD_TAG into CONFIG_BUILD_TAG is probably the best answer and probably not even that bad. I don't think we need an automagic conversion, just noting it in the release emails and the sudden lack of Build: should get people that are using it to update their scripts.
Unfortunately, simply renaming the variable won't work; Kconfig/Kbuild need to know something about it in order to do their rebuild-only-on-change magic (and the value must be removed from CFLAGS too). I was having a hard time getting that to work, but I'll take another look.