Re: [PATCH v2 3/4] alloc_tag: Extend allocinfo_filter to support tracing queries

[Suren Baghdasaryan]

On Thu, Oct 8, 2026 at 2:40 AM Abhishek Bapat <abhishekbapat@xxxxxxxxxx> wrote:
>
> Extend the allocinfo filtering mechanism to allow users to filter tags
> based on their trace state.
>
> Signed-off-by: Abhishek Bapat <abhishekbapat@xxxxxxxxxx>

Acked-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>

> ---
>  include/uapi/linux/alloc_tag.h | 8 ++++++--
>  mm/alloc_tag.c                 | 8 ++++++++
>  2 files changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/include/uapi/linux/alloc_tag.h b/include/uapi/linux/alloc_tag.h
> index dafcba2f7e2c..a96054ac2237 100644
> --- a/include/uapi/linux/alloc_tag.h
> +++ b/include/uapi/linux/alloc_tag.h
> @@ -38,7 +38,8 @@ struct allocinfo_counter {
>         __u64 bytes;
>         __u64 calls;
>         __u8 accurate;
> -       __u8 pad[7];
> +       __u8 trace_on;
> +       __u8 pad[6];
>  } __attribute__((aligned(8)));
>
>  struct allocinfo_tag_data {
> @@ -54,7 +55,8 @@ enum {
>         ALLOCINFO_FILTER_INACCURATE,
>         ALLOCINFO_FILTER_MIN_SIZE,
>         ALLOCINFO_FILTER_MAX_SIZE,
> -       __ALLOCINFO_FILTER_LAST = ALLOCINFO_FILTER_MAX_SIZE
> +       ALLOCINFO_FILTER_TRACE_ON,
> +       __ALLOCINFO_FILTER_LAST = ALLOCINFO_FILTER_TRACE_ON
>  };
>
>  #define ALLOCINFO_FILTER_MASK_MODNAME          (1 << ALLOCINFO_FILTER_MODNAME)
> @@ -64,6 +66,7 @@ enum {
>  #define ALLOCINFO_FILTER_MASK_INACCURATE       (1 << ALLOCINFO_FILTER_INACCURATE)
>  #define ALLOCINFO_FILTER_MASK_MIN_SIZE         (1 << ALLOCINFO_FILTER_MIN_SIZE)
>  #define ALLOCINFO_FILTER_MASK_MAX_SIZE         (1 << ALLOCINFO_FILTER_MAX_SIZE)
> +#define ALLOCINFO_FILTER_MASK_TRACE_ON         (1 << ALLOCINFO_FILTER_TRACE_ON)
>
>  #define ALLOCINFO_FILTER_MASKS \
>         ((1 << (__ALLOCINFO_FILTER_LAST + 1)) - 1)
> @@ -75,6 +78,7 @@ struct allocinfo_filter {
>         __u64 max_size;
>         /* filter criteria only; see allocinfo_counter.accurate for actual accuracy */
>         __u64 inaccurate;
> +       __u64 tracing;
>  };
>
>  struct allocinfo_get_at {
> diff --git a/mm/alloc_tag.c b/mm/alloc_tag.c
> index 262f00f2bba9..8e63f347657b 100644
> --- a/mm/alloc_tag.c
> +++ b/mm/alloc_tag.c
> @@ -250,6 +250,7 @@ static void allocinfo_to_params(struct codetag *ct,
>         data->counter.bytes = counters->bytes;
>         data->counter.calls = counters->calls;
>         data->counter.accurate = !alloc_tag_is_inaccurate(ct_to_alloc_tag(ct));
> +       data->counter.trace_on = alloc_tag_is_traced(ct_to_alloc_tag(ct));
>  }
>
>  /*
> @@ -323,6 +324,13 @@ static bool matches_filter(struct codetag *ct, struct allocinfo_filter *filter,
>                         return false;
>         }
>
> +       if (filter->mask & ALLOCINFO_FILTER_MASK_TRACE_ON) {
> +               bool tracing = alloc_tag_is_traced(ct_to_alloc_tag(ct));
> +
> +               if (tracing != !!(filter->tracing))

nit: Compilers are smart enough nowadays to convert u8 to bool without !!

> +                       return false;
> +       }
> +
>         return true;
>  }
>
> --
> 2.56.0.385.gd3acb90ef8-goog
>