Re: [PATCH 1/2] zsmalloc: require GFP in zs_malloc()

[Minchan Kim <minchan@kernel.org>]

On Fri, Apr 29, 2016 at 01:17:09AM +0900, Sergey Senozhatsky wrote:
> Pass GFP flags to zs_malloc() instead of using a fixed set
> (supplied during pool creation), so we can be more flexible,
> but, more importantly, this will be need to switch zram to
> per-cpu compression streams.
> 
> Apart from that, this also align zs_malloc() interface with
> zspool/zbud.
> 
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> ---
>  drivers/block/zram/zram_drv.c |  2 +-
>  include/linux/zsmalloc.h      |  2 +-
>  mm/zsmalloc.c                 | 15 ++++++---------
>  3 files changed, 8 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index 370c2f7..9030992 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -717,7 +717,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
>  			src = uncmem;
>  	}
>  
> -	handle = zs_malloc(meta->mem_pool, clen);
> +	handle = zs_malloc(meta->mem_pool, clen, GFP_NOIO | __GFP_HIGHMEM);
>  	if (!handle) {
>  		pr_err("Error allocating memory for compressed page: %u, size=%zu\n",
>  			index, clen);
> diff --git a/include/linux/zsmalloc.h b/include/linux/zsmalloc.h
> index 34eb160..6d89f8b 100644
> --- a/include/linux/zsmalloc.h
> +++ b/include/linux/zsmalloc.h
> @@ -44,7 +44,7 @@ struct zs_pool;
>  struct zs_pool *zs_create_pool(const char *name, gfp_t flags);
>  void zs_destroy_pool(struct zs_pool *pool);
>  
> -unsigned long zs_malloc(struct zs_pool *pool, size_t size);
> +unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t flags);
>  void zs_free(struct zs_pool *pool, unsigned long obj);
>  
>  void *zs_map_object(struct zs_pool *pool, unsigned long handle,
> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> index a0890e9..2c22aff 100644
> --- a/mm/zsmalloc.c
> +++ b/mm/zsmalloc.c
> @@ -247,7 +247,6 @@ struct zs_pool {
>  	struct size_class **size_class;
>  	struct kmem_cache *handle_cachep;
>  
> -	gfp_t flags;	/* allocation flags used when growing pool */
>  	atomic_long_t pages_allocated;
>  
>  	struct zs_pool_stats stats;
> @@ -295,10 +294,10 @@ static void destroy_handle_cache(struct zs_pool *pool)
>  	kmem_cache_destroy(pool->handle_cachep);
>  }
>  
> -static unsigned long alloc_handle(struct zs_pool *pool)
> +static unsigned long alloc_handle(struct zs_pool *pool, gfp_t gfp)
>  {
>  	return (unsigned long)kmem_cache_alloc(pool->handle_cachep,
> -		pool->flags & ~__GFP_HIGHMEM);
> +			gfp & ~__GFP_HIGHMEM);
>  }
>  
>  static void free_handle(struct zs_pool *pool, unsigned long handle)
> @@ -335,7 +334,7 @@ static void zs_zpool_destroy(void *pool)
>  static int zs_zpool_malloc(void *pool, size_t size, gfp_t gfp,
>  			unsigned long *handle)
>  {
> -	*handle = zs_malloc(pool, size);
> +	*handle = zs_malloc(pool, size, gfp);
>  	return *handle ? 0 : -1;
>  }
>  static void zs_zpool_free(void *pool, unsigned long handle)
> @@ -1391,7 +1390,7 @@ static unsigned long obj_malloc(struct size_class *class,
>   * otherwise 0.
>   * Allocation requests with size > ZS_MAX_ALLOC_SIZE will fail.
>   */
> -unsigned long zs_malloc(struct zs_pool *pool, size_t size)
> +unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp)
>  {
>  	unsigned long handle, obj;
>  	struct size_class *class;
> @@ -1400,7 +1399,7 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size)
>  	if (unlikely(!size || size > ZS_MAX_ALLOC_SIZE))
>  		return 0;
>  
> -	handle = alloc_handle(pool);
> +	handle = alloc_handle(pool, gfp);
>  	if (!handle)
>  		return 0;
>  
> @@ -1413,7 +1412,7 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size)
>  
>  	if (!first_page) {
>  		spin_unlock(&class->lock);
> -		first_page = alloc_zspage(class, pool->flags);
> +		first_page = alloc_zspage(class, gfp);
>  		if (unlikely(!first_page)) {
>  			free_handle(pool, handle);
>  			return 0;
> @@ -1945,8 +1944,6 @@ struct zs_pool *zs_create_pool(const char *name, gfp_t flags)

So, we can remove flags parameter passing and comment about that.

Other than that,

Acked-by: Minchan Kim <minchan@kernel.org>