From: Bijan Tabatabai <bijantabatab@micron.com>

This patch exposes get_il_weight() in mm/internal.h. This patch is to
allow other parts of the MM subsystem, such as DAMON, to make page
placement decisions based on the global interleave weights.

Signed-off-by: Bijan Tabatabai <bijantabatab@micron.com>
---
 mm/internal.h  | 6 ++++++
 mm/mempolicy.c | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/mm/internal.h b/mm/internal.h
index 3823fb356d3b..b718ebe7cad5 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1169,6 +1169,7 @@ extern int node_reclaim_mode;
 
 extern int node_reclaim(struct pglist_data *, gfp_t, unsigned int);
 extern int find_next_best_node(int node, nodemask_t *used_node_mask);
+extern u8 get_il_weight(int node);
 #else
 #define node_reclaim_mode 0
 
@@ -1181,6 +1182,11 @@ static inline int find_next_best_node(int node, nodemask_t *used_node_mask)
 {
 	return NUMA_NO_NODE;
 }
+
+static inline u8 get_il_weight(int node)
+{
+	return 1;
+}
 #endif
 
 static inline bool node_reclaim_enabled(void)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 1ff7b2174eb7..b1713430ee9c 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -165,7 +165,7 @@ static unsigned int *node_bw_table;
  */
 static DEFINE_MUTEX(wi_state_lock);
 
-static u8 get_il_weight(int node)
+u8 get_il_weight(int node)
 {
 	struct weighted_interleave_state *state;
 	u8 weight = 1;
-- 
2.43.5

Bijan Tabatabai <bijan311@gmail.com> writes:

> From: Bijan Tabatabai <bijantabatab@micron.com>
>
> This patch exposes get_il_weight() in mm/internal.h. This patch is to
> allow other parts of the MM subsystem, such as DAMON, to make page
> placement decisions based on the global interleave weights.
>
> Signed-off-by: Bijan Tabatabai <bijantabatab@micron.com>
> ---
>  mm/internal.h  | 6 ++++++
>  mm/mempolicy.c | 2 +-
>  2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/mm/internal.h b/mm/internal.h
> index 3823fb356d3b..b718ebe7cad5 100644
> --- a/mm/internal.h
> +++ b/mm/internal.h
> @@ -1169,6 +1169,7 @@ extern int node_reclaim_mode;
>  
>  extern int node_reclaim(struct pglist_data *, gfp_t, unsigned int);
>  extern int find_next_best_node(int node, nodemask_t *used_node_mask);
> +extern u8 get_il_weight(int node);
>  #else
>  #define node_reclaim_mode 0
>  
> @@ -1181,6 +1182,11 @@ static inline int find_next_best_node(int node, nodemask_t *used_node_mask)
>  {
>  	return NUMA_NO_NODE;
>  }
> +
> +static inline u8 get_il_weight(int node)
> +{
> +	return 1;
> +}
>  #endif
>  
>  static inline bool node_reclaim_enabled(void)
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 1ff7b2174eb7..b1713430ee9c 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -165,7 +165,7 @@ static unsigned int *node_bw_table;
>   */
>  static DEFINE_MUTEX(wi_state_lock);
>  
> -static u8 get_il_weight(int node)
> +u8 get_il_weight(int node)
>  {
>  	struct weighted_interleave_state *state;
>  	u8 weight = 1;

I agree with David on the function naming and "extern".  Otherwise, this
looks good to me, Thanks!  Feel free to add my

Reviewed-by: Huang Ying <ying.huang@linux.alibaba.com>

in the future versions.

---
Best Regards,
Huang, Ying

On 20.06.25 20:04, Bijan Tabatabai wrote:
> From: Bijan Tabatabai <bijantabatab@micron.com>
> 
> This patch exposes get_il_weight() in mm/internal.h. This patch is to
> allow other parts of the MM subsystem, such as DAMON, to make page
> placement decisions based on the global interleave weights.
> 
> Signed-off-by: Bijan Tabatabai <bijantabatab@micron.com>
> ---
>   mm/internal.h  | 6 ++++++
>   mm/mempolicy.c | 2 +-
>   2 files changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/internal.h b/mm/internal.h
> index 3823fb356d3b..b718ebe7cad5 100644
> --- a/mm/internal.h
> +++ b/mm/internal.h
> @@ -1169,6 +1169,7 @@ extern int node_reclaim_mode;
>   
>   extern int node_reclaim(struct pglist_data *, gfp_t, unsigned int);
>   extern int find_next_best_node(int node, nodemask_t *used_node_mask);
> +extern u8 get_il_weight(int node);

No new "extern". It's a blast from the past :)

>   #else
>   #define node_reclaim_mode 0
>   
> @@ -1181,6 +1182,11 @@ static inline int find_next_best_node(int node, nodemask_t *used_node_mask)
>   {
>   	return NUMA_NO_NODE;
>   }
> +
> +static inline u8 get_il_weight(int node)
> +{
> +	return 1;
> +}
>   #endif
>   
>   static inline bool node_reclaim_enabled(void)
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 1ff7b2174eb7..b1713430ee9c 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -165,7 +165,7 @@ static unsigned int *node_bw_table;
>    */
>   static DEFINE_MUTEX(wi_state_lock);
>   
> -static u8 get_il_weight(int node)
> +u8 get_il_weight(int node)

The function name is shockingly confusing when used outside this file. 
Do we have some namespace to at least highlight what this is about?

node_interleave_weight() might be a lot clearer?

So maybe let's just rename it to something less confusing as we use it 
from other files.

>   {
>   	struct weighted_interleave_state *state;
>   	u8 weight = 1;


-- 
Cheers,

David / dhildenb

On Mon, Jun 23, 2025 at 09:14:34PM +0200, David Hildenbrand wrote:
> > +u8 get_il_weight(int node)
> 
> The function name is shockingly confusing when used outside this file. Do we
> have some namespace to at least highlight what this is about?
> 
> node_interleave_weight() might be a lot clearer?
> 

this is fair and my fault as I didn't consider whether it'd ever be used
outside mempolicy.  So i agree it should be renamed or wrapped.

~Gregory

On Fri, Jun 20, 2025 at 01:04:57PM -0500, Bijan Tabatabai wrote:
> From: Bijan Tabatabai <bijantabatab@micron.com>
> 
> This patch exposes get_il_weight() in mm/internal.h. This patch is to
> allow other parts of the MM subsystem, such as DAMON, to make page
> placement decisions based on the global interleave weights.
> 
> Signed-off-by: Bijan Tabatabai <bijantabatab@micron.com>

Reviewed-by: Gregory Price <gourry@gourry.net>