Re: [PATCH 2/5] zsmalloc: Consolidate zs_pool's migrate_lock and size_class's locks

[Sergey Senozhatsky]

On (22/10/26 13:06), Nhat Pham wrote:
>  struct size_class {
> -	spinlock_t lock;
>  	struct list_head fullness_list[NR_ZS_FULLNESS];
>  	/*
>  	 * Size of objects stored in this class. Must be multiple
> @@ -247,8 +245,7 @@ struct zs_pool {
>  #ifdef CONFIG_COMPACTION
>  	struct work_struct free_work;
>  #endif
> -	/* protect page/zspage migration */
> -	rwlock_t migrate_lock;
> +	spinlock_t lock;
>  };

I'm not in love with this, to be honest. One big pool lock instead
of 255 per-class locks doesn't look attractive, as one big pool lock
is going to be hammered quite a lot when zram is used, e.g. as a regular
block device with a file system and is under heavy parallel writes/reads.