Each calll to a KUNIT_EXPECT_*() macro creates a local variable which
contains a struct kunit_assert.
Normally, we'd hope the compiler would be able to optimize this away,
but we've seen cases where it hasn't, see
https://groups.google.com/g/kunit-dev/c/i3fZXgvBrfA/m/GbrMNej2BAAJ.
In changes like commit 21957f90b2 ("kunit: split out part of
kunit_assert into a static const"), we've moved more and more parts out
of struct kunit_assert and its children types (kunit_binary_assert).
This patch removes the final field and gets us to:
sizeof(struct kunit_assert) == 0
sizeof(struct kunit_binary_assert) == 24 (on UML x86_64).
This also reduces the amount of macro plumbing going on at the cost of
passing in one more arg to the base KUNIT_ASSERTION macro and
kunit_do_failed_assertion().
Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
If the compiler doesn't optimize them away, each kunit assertion (use of
KUNIT_EXPECT_EQ, etc.) can use 88 bytes of stack space in the worst and
most common case. This has led to compiler warnings and a suggestion
from Linus to move data from the structs into static const's where
possible [1].
This builds upon [2] which did so for the base struct kunit_assert type.
That only reduced sizeof(struct kunit_binary_assert) from 88 to 64.
Given these are by far the most commonly used asserts, this patch
factors out the textual representations of the operands and comparator
into another static const, saving 16 more bytes.
In detail, KUNIT_EXPECT_EQ(test, 2 + 2, 5) yields the following struct
(struct kunit_binary_assert) {
.assert = <struct kunit_assert>,
.operation = "==",
.left_text = "2 + 2",
.left_value = 4,
.right_text = "5",
.right_value = 5,
}
After this change
static const struct kunit_binary_assert_text __text = {
.operation = "==",
.left_text = "2 + 2",
.right_text = "5",
};
(struct kunit_binary_assert) {
.assert = <struct kunit_assert>,
.text = &__text,
.left_value = 4,
.right_value = 5,
}
This also DRYs the code a bit more since these str fields were repeated
for the string and pointer versions of kunit_binary_assert.
Note: we could name the kunit_binary_assert_text fields left/right
instead of left_text/right_text. But that would require changing the
macros a bit since they have args called "left" and "right" which would
be substituted in `.left = #left` as `.2 + 2 = \"2 + 2\"`.
[1] https://groups.google.com/g/kunit-dev/c/i3fZXgvBrfA/m/VULQg1z6BAAJ
[2] https://lore.kernel.org/linux-kselftest/20220113165931.451305-6-dlatypov@google.com/
Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
We currently have 2 other versions of KUNIT_INIT_BINARY_ASSERT_STRUCT.
The only differences are that
* the format funcition they pass is different
* the types of left_val/right_val should be different (integral,
pointer, string).
The latter doesn't actually matter since these macros are just plumbing
them along to KUNIT_ASSERTION where they will get type checked.
So combine them all into a single KUNIT_INIT_BINARY_ASSERT_STRUCT that
now also takes the format function as a parameter.
Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
The concern is that having a lot of redundant fields in kunit_assert can
blow up stack usage if the compiler doesn't optimize them away [1].
The comment on this field implies that it was meant to be initialized
when the expect/assert was declared, but this only happens when we run
kunit_do_failed_assertion().
We don't need to access it outside of that function, so move it out of
the struct and make it a local variable there.
This change also takes the chance to reduce the number of macros by
inlining the now simplified KUNIT_INIT_ASSERT_STRUCT() macro.
[1] https://groups.google.com/g/kunit-dev/c/i3fZXgvBrfA/m/VULQg1z6BAAJ
Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
This field has been split out from kunit_assert to make the struct less
heavy along with the filename and line number.
This change drops the assert_type field and cleans up all the macros
that were plumbing assert_type into kunit_assert.
Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
This is per Linus's suggestion in [1].
The issue there is that every KUNIT_EXPECT/KUNIT_ASSERT puts a
kunit_assert object onto the stack. Normally we rely on compilers to
elide this, but when that doesn't work out, this blows up the stack
usage of kunit test functions.
We can move some data off the stack by making it static.
This change introduces a new `struct kunit_loc` to hold the file and
line number and then just passing assert_type (EXPECT or ASSERT) as an
argument.
In [1], it was suggested to also move out the format string as well, but
users could theoretically craft a format string at runtime, so we can't.
This change leaves a copy of `assert_type` in kunit_assert for now
because cleaning up all the macros to not pass it around is a bit more
involved.
Here's an example of the expanded code for KUNIT_FAIL():
if (__builtin_expect(!!(!(false)), 0)) {
static const struct kunit_loc loc = { .file = ... };
struct kunit_fail_assert __assertion = { .assert = { .type ... };
kunit_do_failed_assertion(test, &loc, KUNIT_EXPECTATION, &__assertion.assert, ...);
};
[1] https://groups.google.com/g/kunit-dev/c/i3fZXgvBrfA/m/VULQg1z6BAAJ
Signed-off-by: Daniel Latypov <dlatypov@google.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
The `struct kunit* test` field in kunit_assert is unused.
Note: string_stream needs it, but it has its own `test` field. I assume
`test` in `kunit_assert` predates this and was leftover after some
refactoring.
This patch removes the field and cleans up the macros to avoid
needlessly passing around `test`.
Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
When kernel.h is used in the headers it adds a lot into dependency hell,
especially when there are circular dependencies are involved.
Replace kernel.h inclusion with the list of what is really being used.
Link: https://lkml.kernel.org/r/20211213204441.56204-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Tested-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add `struct kunit_assert` and friends which provide a structured way to
capture data from an expectation or an assertion (introduced later in
the series) so that it may be printed out in the event of a failure.
Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
