Re: [PATCH v2 2/4] mm: vmscan: propagate real error code from per-node proactive reclaim

[Qi Zheng <qi.zheng@linux.dev>]

On 7/18/26 5:52 PM, Ridong Chen wrote:
> From: Ridong Chen <chenridong@xiaomi.com>
> 
> It has been observed that per-node proactive reclaim always returns
> -EAGAIN when any error occurs. As discussed in the mailing list [1],
> the interface should distinguish between cases where no reclaimable
> memory is left and where another entity is concurrently using the
> same interface. Propagate the real error code, consistent with how
> memcg proactive reclaim handles errors.
> 
> [1] https://lore.kernel.org/all/20250717235604.2atyx2aobwowpge3@offworld/T/#m3514718be82a31b05726a49da9b61fbfc69a589e
> 
> Fixes: b980077899ea ("mm: introduce per-node proactive reclaim interface")
> Reviewed-by: Muchun Song <muchun.song@linux.dev>
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
> Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
> Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
> ---
>   mm/vmscan.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index d6b383d96a0c..cfe4556c96d7 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -8017,7 +8017,7 @@ static ssize_t reclaim_store(struct device *dev,
>   	int ret, nid = dev->id;
>   
>   	ret = user_proactive_reclaim((char *)buf, NULL, NODE_DATA(nid));
> -	return ret ? -EAGAIN : count;
> +	return ret ? ret : count;
>   }
>   
>   static DEVICE_ATTR_WO(reclaim);

Nice catch!

Reviewed-by: Qi Zheng <qi.zheng@linux.dev>

Thanks,
Qi