On 3/31/22 16:03, Stéphane Graber wrote:
> Commit 64dd68497be76 relocated and renamed the alloc_calls and
> free_calls files from /sys/kernel/slab/NAME/*_calls over to
> /sys/kernel/debug/slab/NAME/*_calls but didn't update the slabinfo tool
> with the new location.
>
> This change will now have slabinfo look at the new location (and filenames)
> with a fallback to the prior files.
>
> Fixes: 64dd68497be76 ("mm: slub: move sysfs slab alloc/free interfaces to debugfs")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Stéphane Graber <stgraber@xxxxxxxxxx>
> Tested-by: Stéphane Graber <stgraber@xxxxxxxxxx>
> ---
> tools/vm/slabinfo.c | 26 ++++++++++++++++++++++++--
> 1 file changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/tools/vm/slabinfo.c b/tools/vm/slabinfo.c
> index 9b68658b6bb8..5b98f3ee58a5 100644
> --- a/tools/vm/slabinfo.c
> +++ b/tools/vm/slabinfo.c
> @@ -233,6 +233,24 @@ static unsigned long read_slab_obj(struct slabinfo *s, const char *name)
> return l;
> }
>
> +static unsigned long read_debug_slab_obj(struct slabinfo *s, const char *name)
> +{
> + char x[128];
> + FILE *f;
> + size_t l;
> +
> + snprintf(x, 128, "/sys/kernel/debug/slab/%s/%s", s->name, name);
> + f = fopen(x, "r");
> + if (!f) {
> + buffer[0] = 0;
> + l = 0;
> + } else {
> + l = fread(buffer, 1, sizeof(buffer), f);
> + buffer[l] = 0;
> + fclose(f);
> + }
> + return l;
> +}
slabinfo is not the nicest code already, but still this basically duplicates
read_slab_obj() just to add a prefix to the path, so it could be done in a
unified way?
>
> /*
> * Put a size string together
> @@ -409,14 +427,18 @@ static void show_tracking(struct slabinfo *s)
> {
> printf("\n%s: Kernel object allocation\n", s->name);
> printf("-----------------------------------------------------------------------\n");
> - if (read_slab_obj(s, "alloc_calls"))
> + if (read_debug_slab_obj(s, "alloc_traces"))
> + printf("%s", buffer);
> + else if (read_slab_obj(s, "alloc_calls"))
> printf("%s", buffer);
> else
> printf("No Data\n");
>
> printf("\n%s: Kernel object freeing\n", s->name);
> printf("------------------------------------------------------------------------\n");
> - if (read_slab_obj(s, "free_calls"))
> + if (read_debug_slab_obj(s, "free_traces"))
> + printf("%s", buffer);
> + else if (read_slab_obj(s, "free_calls"))
> printf("%s", buffer);
> else
> printf("No Data\n");
