On Sat, Nov 20, 2021 at 5:17 AM Daniel Latypov <dlatypov@xxxxxxxxxx> wrote: > > On Thu, Nov 18, 2021 at 11:04 PM David Gow <davidgow@xxxxxxxxxx> wrote: > > > > On Fri, Nov 19, 2021 at 3:03 AM 'Daniel Latypov' via KUnit Development > > <kunit-dev@xxxxxxxxxxxxxxxx> wrote: > > > > > > Problem: currently, if you remove something from your kunitconfig, > > > kunit.py will not regenerate the .config file. > > > The same thing happens if you did --kunitconfig_add=CONFIG_KASAN=y [1] > > > and then ran again without it. Your new run will still have KASAN. > > > > > > The reason is that kunit.py won't regenerate the .config file if it's a > > > superset of the kunitconfig. This speeds it up a bit for iterating. > > > > > > This patch adds an additional check that forces kunit.py to regenerate > > > the .config file if the current kunitconfig doesn't match the previous > > > one. > > > > > > What this means: > > > * deleting entries from .kunitconfig works as one would expect > > > * dropping a --kunitconfig_add also triggers a rebuild > > > * you can still edit .config directly to turn on new options > > > > > > We implement this by creating a `last_used_kunitconfig` file in the > > > build directory (so .kunit, by default) after we generate the .config. > > > When comparing the kconfigs, we compare python sets, so duplicates and > > > permutations don't trip us up. > > > > > > The majority of this patch is adding unit tests for the existing logic > > > and for the new case where `last_used_kunitconfig` differs. > > > > > > [1] https://lore.kernel.org/linux-kselftest/20211106013058.2621799-2-dlatypov@xxxxxxxxxx/ > > > > > > Signed-off-by: Daniel Latypov <dlatypov@xxxxxxxxxx> > > > --- > > > > Note that this patch has some prerequisites before it applies cleanly, > > notably this series: > > https://patchwork.kernel.org/project/linux-kselftest/list/?series=576317 > > > > I'm also seeing a couple of issues with this, though I haven't had a > > chance to track down the cause fully, so it could just be another > > missing prerequisite, or me doing something silly. > > > > In particular: > > - Removing items from .kunit/.kunitconfig still wasn't triggering a reconfig. > > This is an edge case that only comes up the absolute first time you > switch to using kunit.py with this change. > > If there's no last_used_kunitconfig file, this new check doesn't do anything. > See how it returns False when the file doesn't exist in _kconfig_changed(). > > Given you hit the error below about last_used_kunitconfig not > existing, I'm 99% this is what you ran into. > > The file is currently only generated if we actually call `make oldefconfig`. > So if you just run `kunit.py run` a few times after this change with > no config changes, last_used_kunitconfig won't be created, and the new > check won't kick in. > > We can avoid this one-time confusion by > * make _kconfig_changed() return True if last_used_kunitconfig doesn't > exist, since maybe the config did change. > * or always write last_used_kunitconfig on every invocation. > > The first would trigger a false positive the first time a user uses > kunit.py after this change goes in. > It also lightly penalizes the user for messing with `last_used_kunitconfig`. This seems like a good compromise to me: people are likely to get this change only after a major kernel release, and re-configuring then (even if not strictly necessary) doesn't seem totally silly. Equally, I think it's best for the behaviour to change exactly when the change goes in, rather than some unspecified time afterwards. > > The second adds some overhead that isn't really necessary most of the time. > It also won't help with the absolute first time you run kunit.py after > this change. > But it will make it so the second time onwards will have the logic enabled. > > So I'd personally prefer we leave it as-is. > To most users, this will be a transparent change, so there's no > expectations about it coming into play immediately. As mentioned above, I'd prefer this be a little less transparent and come into play immediately. I don't think one extra reconfigure will be a problem for most users, and it'll be obvious it's caused by an update. Equally, I don't expect people will mess with `last_used_kunitconfig`, so that shouldn't be a problem? > > > - Running with --arch=x86_64 was giving me a "FileNotFoundError: > > Ah, this should be unrelated to --arch. > os.remove() throws an exception if the argument doesn't exist. > > So the fix is > + if os.path.exists(old_path) > os.remove(old_path) # write_to_file appends to the file Ah... makes sense. Let's fix this in the next revision. > And ah, that didn't get caught by the added unit test since > build_config() is mocked out and it's in there, no build_reconfig(). > > So, could we have these changes for v2: - Reconfigure if there's no last_used_kunitconfig - Fix the os.remove() issue if last_used_kunitconfig doesn't exist. - Note the dependencies for this to merge cleanly in the email. Does that sound sensible? -- David
