Re: [PATCH v3 3/4] alloc_tag: Extend allocinfo_filter to support tracing queries

[Hao Ge <hao.ge@linux.dev>]

On 2026/10/20 04:00, Abhishek Bapat wrote:
> Extend the allocinfo filtering mechanism to allow users to filter tags
> based on their trace state.
> 
> Signed-off-by: Abhishek Bapat <abhishekbapat@google.com>
> Acked-by: Suren Baghdasaryan <surenb@google.com>

Acked-by: Hao Ge <hao.ge@linux.dev>

> ---
>  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 9ff9dd04d692..0d4d267c065f 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))

I recall Suren had a small nit on this hunk in the previous version.
I don't see this change here, did I miss something?

> +			return false;
> +	}
> +
>  	return true;
>  }
>