2021-11-05 17:13:46

by Anders Roxell

Subject: [PATCH 2/2] selftests: cgroup: use function 'labs()' over 'abs()'

When building selftests/cgroup with clang, the compiler warn about the
function abs() see below:

In file included from test_memcontrol.c:21:
./cgroup_util.h:16:9: warning: absolute value function 'abs' given an argument of type 'long' but has parameter of type 'int' which may cause truncation of value [-Wabsolute-value]
return abs(a - b) <= (a + b) / 100 * err;
^
./cgroup_util.h:16:9: note: use function 'labs' instead
return abs(a - b) <= (a + b) / 100 * err;
^~~
labs

The note indicates what to do, Rework to use the function 'labs()'.

Signed-off-by: Anders Roxell <[email protected]>
---
tools/testing/selftests/cgroup/cgroup_util.h | 2 +-
tools/testing/selftests/cgroup/test_kmem.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/cgroup/cgroup_util.h b/tools/testing/selftests/cgroup/cgroup_util.h
index 82e59cdf16e7..76b35d9dffb5 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.h
+++ b/tools/testing/selftests/cgroup/cgroup_util.h
@@ -13,7 +13,7 @@
*/
static inline int values_close(long a, long b, int err)
{
- return abs(a - b) <= (a + b) / 100 * err;
+ return labs(a - b) <= (a + b) / 100 * err;
}

extern int cg_find_unified_root(char *root, size_t len);
diff --git a/tools/testing/selftests/cgroup/test_kmem.c b/tools/testing/selftests/cgroup/test_kmem.c
index 22b31ebb3513..d65bb8fe876a 100644
--- a/tools/testing/selftests/cgroup/test_kmem.c
+++ b/tools/testing/selftests/cgroup/test_kmem.c
@@ -192,7 +192,7 @@ static int test_kmem_memcg_deletion(const char *root)
goto cleanup;

sum = slab + anon + file + kernel_stack + pagetables + percpu + sock;
- if (abs(sum - current) < MAX_VMSTAT_ERROR) {
+ if (labs(sum - current) < MAX_VMSTAT_ERROR) {
ret = KSFT_PASS;
} else {
printf("memory.current = %ld\n", current);
@@ -383,7 +383,7 @@ static int test_percpu_basic(const char *root)
current = cg_read_long(parent, "memory.current");
percpu = cg_read_key_long(parent, "memory.stat", "percpu ");

- if (current > 0 && percpu > 0 && abs(current - percpu) <
+ if (current > 0 && percpu > 0 && labs(current - percpu) <
MAX_VMSTAT_ERROR)
ret = KSFT_PASS;
else
--
2.33.0

2021-11-05 20:31:43

by Nick Desaulniers

Subject: Re: [PATCH 2/2] selftests: cgroup: use function 'labs()' over 'abs()'

On Fri, Nov 5, 2021 at 9:25 AM Anders Roxell <[email protected]> wrote:
>
> When building selftests/cgroup with clang, the compiler warn about the
> function abs() see below:
>
> In file included from test_memcontrol.c:21:
> ./cgroup_util.h:16:9: warning: absolute value function 'abs' given an argument of type 'long' but has parameter of type 'int' which may cause truncation of value [-Wabsolute-value]
> return abs(a - b) <= (a + b) / 100 * err;
> ^
> ./cgroup_util.h:16:9: note: use function 'labs' instead
> return abs(a - b) <= (a + b) / 100 * err;
> ^~~
> labs
>
> The note indicates what to do, Rework to use the function 'labs()'.
>
> Signed-off-by: Anders Roxell <[email protected]>

Thanks for the patch!
Reviewed-by: Nick Desaulniers <[email protected]>

> ---
> tools/testing/selftests/cgroup/cgroup_util.h | 2 +-
> tools/testing/selftests/cgroup/test_kmem.c | 4 ++--
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/tools/testing/selftests/cgroup/cgroup_util.h b/tools/testing/selftests/cgroup/cgroup_util.h
> index 82e59cdf16e7..76b35d9dffb5 100644
> --- a/tools/testing/selftests/cgroup/cgroup_util.h
> +++ b/tools/testing/selftests/cgroup/cgroup_util.h
> @@ -13,7 +13,7 @@
> */
> static inline int values_close(long a, long b, int err)
> {
> - return abs(a - b) <= (a + b) / 100 * err;
> + return labs(a - b) <= (a + b) / 100 * err;
> }
>
> extern int cg_find_unified_root(char *root, size_t len);
> diff --git a/tools/testing/selftests/cgroup/test_kmem.c b/tools/testing/selftests/cgroup/test_kmem.c
> index 22b31ebb3513..d65bb8fe876a 100644
> --- a/tools/testing/selftests/cgroup/test_kmem.c
> +++ b/tools/testing/selftests/cgroup/test_kmem.c
> @@ -192,7 +192,7 @@ static int test_kmem_memcg_deletion(const char *root)
> goto cleanup;
>
> sum = slab + anon + file + kernel_stack + pagetables + percpu + sock;
> - if (abs(sum - current) < MAX_VMSTAT_ERROR) {
> + if (labs(sum - current) < MAX_VMSTAT_ERROR) {
> ret = KSFT_PASS;
> } else {
> printf("memory.current = %ld\n", current);
> @@ -383,7 +383,7 @@ static int test_percpu_basic(const char *root)
> current = cg_read_long(parent, "memory.current");
> percpu = cg_read_key_long(parent, "memory.stat", "percpu ");
>
> - if (current > 0 && percpu > 0 && abs(current - percpu) <
> + if (current > 0 && percpu > 0 && labs(current - percpu) <
> MAX_VMSTAT_ERROR)
> ret = KSFT_PASS;
> else
> --
> 2.33.0
>


--
Thanks,
~Nick Desaulniers

2021-11-09 23:59:30

by Christian Brauner

Subject: Re: [PATCH 2/2] selftests: cgroup: use function 'labs()' over 'abs()'

On Fri, Nov 05, 2021 at 05:25:30PM +0100, Anders Roxell wrote:
> When building selftests/cgroup with clang, the compiler warn about the
> function abs() see below:
>
> In file included from test_memcontrol.c:21:
> ./cgroup_util.h:16:9: warning: absolute value function 'abs' given an argument of type 'long' but has parameter of type 'int' which may cause truncation of value [-Wabsolute-value]
> return abs(a - b) <= (a + b) / 100 * err;
> ^
> ./cgroup_util.h:16:9: note: use function 'labs' instead
> return abs(a - b) <= (a + b) / 100 * err;
> ^~~
> labs
>
> The note indicates what to do, Rework to use the function 'labs()'.
>
> Signed-off-by: Anders Roxell <[email protected]>
> ---

Thanks!
Acked-by: Christian Brauner <[email protected]>