Re: [PATCH v3 3/4] mm: add system wide stats items category

[David Hildenbrand <david@redhat.com>]

On 08.08.24 17:42, Pasha Tatashin wrote:
> /proc/vmstat contains events and stats, events can only grow, but stats
> can grow and srhink.

s/shrink/

I think we discussed exposing this in /proc/meminfo. There, it would be 
much easier to simply have a global variable, print it, and be done with 
it. Like we do with TotalCma.

For /proc/vmstat that's likely the right approach what you have here.

> 
> vmstat has the following:
> -------------------------
> NR_VM_ZONE_STAT_ITEMS:	per-zone stats
> NR_VM_NUMA_EVENT_ITEMS:	per-numa events
> NR_VM_NODE_STAT_ITEMS:	per-numa stats
> NR_VM_WRITEBACK_STAT_ITEMS:	system-wide background-writeback and
> 				dirty-throttling tresholds.
> NR_VM_EVENT_ITEMS:	system-wide events
> -------------------------
> 
> Rename NR_VM_WRITEBACK_STAT_ITEMS to NR_VM_STAT_ITEMS, to track the
> system-wide stats, we are going to add per-page metadata stats to this
> category in the next patch.
> 
> Also delete unused writeback_stat_name() function.
> 
> Suggested-by: Yosry Ahmed <yosryahmed@google.com>
> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
> ---
>   include/linux/vmstat.h | 15 ++++-----------
>   mm/vmstat.c            |  6 +++---
>   2 files changed, 7 insertions(+), 14 deletions(-)
> 
> diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
> index 23cd17942036..9ab4fa5e09b5 100644
> --- a/include/linux/vmstat.h
> +++ b/include/linux/vmstat.h
> @@ -34,10 +34,11 @@ struct reclaim_stat {
>   	unsigned nr_lazyfree_fail;
>   };
>   
> -enum writeback_stat_item {
> +/* Stat data for system wide items */
> +enum vm_stat_item {
>   	NR_DIRTY_THRESHOLD,
>   	NR_DIRTY_BG_THRESHOLD,
> -	NR_VM_WRITEBACK_STAT_ITEMS,
> +	NR_VM_STAT_ITEMS,
>   };
>   
>   #ifdef CONFIG_VM_EVENT_COUNTERS
> @@ -514,21 +515,13 @@ static inline const char *lru_list_name(enum lru_list lru)
>   	return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
>   }
>   
> -static inline const char *writeback_stat_name(enum writeback_stat_item item)
> -{
> -	return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
> -			   NR_VM_NUMA_EVENT_ITEMS +
> -			   NR_VM_NODE_STAT_ITEMS +
> -			   item];
> -}
> -
>   #if defined(CONFIG_VM_EVENT_COUNTERS) || defined(CONFIG_MEMCG)
>   static inline const char *vm_event_name(enum vm_event_item item)
>   {
>   	return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
>   			   NR_VM_NUMA_EVENT_ITEMS +
>   			   NR_VM_NODE_STAT_ITEMS +
> -			   NR_VM_WRITEBACK_STAT_ITEMS +
> +			   NR_VM_STAT_ITEMS +
>   			   item];
>   }
>   #endif /* CONFIG_VM_EVENT_COUNTERS || CONFIG_MEMCG */
> diff --git a/mm/vmstat.c b/mm/vmstat.c
> index 04a1cb6cc636..6f8aa4766f16 100644
> --- a/mm/vmstat.c
> +++ b/mm/vmstat.c
> @@ -1257,7 +1257,7 @@ const char * const vmstat_text[] = {
>   	"pgdemote_khugepaged",
>   	"nr_memmap",
>   	"nr_memmap_boot",
> -	/* enum writeback_stat_item counters */
> +	/* system-wide enum vm_stat_item counters */
>   	"nr_dirty_threshold",
>   	"nr_dirty_background_threshold",
>   
> @@ -1790,7 +1790,7 @@ static const struct seq_operations zoneinfo_op = {
>   #define NR_VMSTAT_ITEMS (NR_VM_ZONE_STAT_ITEMS + \
>   			 NR_VM_NUMA_EVENT_ITEMS + \
>   			 NR_VM_NODE_STAT_ITEMS + \
> -			 NR_VM_WRITEBACK_STAT_ITEMS + \
> +			 NR_VM_STAT_ITEMS + \
>   			 (IS_ENABLED(CONFIG_VM_EVENT_COUNTERS) ? \
>   			  NR_VM_EVENT_ITEMS : 0))
>   
> @@ -1827,7 +1827,7 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos)
>   
>   	global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
>   			    v + NR_DIRTY_THRESHOLD);
> -	v += NR_VM_WRITEBACK_STAT_ITEMS;
> +	v += NR_VM_STAT_ITEMS;
>   
>   #ifdef CONFIG_VM_EVENT_COUNTERS
>   	all_vm_events(v);

-- 
Cheers,

David / dhildenb