Re: [PATCH 3/3] zram: use common zpool interface

[Sergey Senozhatsky]

On (09/14/15 15:55), Vitaly Wool wrote:
> Update zram driver to use common zpool API instead of calling
> zsmalloc functions directly. This patch also adds a parameter
> that allows for changing underlying compressor storage to zbud.
> 
> Signed-off-by: Vitaly Wool <vitalywool@xxxxxxxxx>
> ---
>  drivers/block/zram/Kconfig    |  3 ++-
>  drivers/block/zram/zram_drv.c | 44 ++++++++++++++++++++++++-------------------
>  drivers/block/zram/zram_drv.h |  4 ++--
>  3 files changed, 29 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/block/zram/Kconfig b/drivers/block/zram/Kconfig
> index 386ba3d..4831d0a 100644
> --- a/drivers/block/zram/Kconfig
> +++ b/drivers/block/zram/Kconfig
> @@ -1,6 +1,7 @@
>  config ZRAM
>  	tristate "Compressed RAM block device support"
> -	depends on BLOCK && SYSFS && ZSMALLOC
> +	depends on BLOCK && SYSFS
> +	select ZPOOL

well, in that case, all `#ifdef CONFIG_ZPOOL' in zsmalloc can be dropped,
because now it's a must have.


>  	select LZO_COMPRESS
>  	select LZO_DECOMPRESS
>  	default n
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index 49d5a65..2829c3d 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -44,6 +44,9 @@ static const char *default_compressor = "lzo";
>  static unsigned int num_devices = 1;
>  static size_t max_zpage_size = PAGE_SIZE / 4 * 3;
>  
> +#define ZRAM_ZPOOL_DEFAULT "zsmalloc"
> +static char *pool_type = ZRAM_ZPOOL_DEFAULT;
> +
>  static inline void deprecated_attr_warn(const char *name)
>  {
>  	pr_warn_once("%d (%s) Attribute %s (and others) will be removed. %s\n",
> @@ -229,11 +232,11 @@ static ssize_t mem_used_total_show(struct device *dev,
>  	down_read(&zram->init_lock);
>  	if (init_done(zram)) {
>  		struct zram_meta *meta = zram->meta;
> -		val = zs_get_total_pages(meta->mem_pool);
> +		val = zpool_get_total_size(meta->mem_pool);
>  	}
>  	up_read(&zram->init_lock);
>  
> -	return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT);
> +	return scnprintf(buf, PAGE_SIZE, "%llu\n", val);
>  }
>  
>  static ssize_t mem_limit_show(struct device *dev,
> @@ -298,7 +301,7 @@ static ssize_t mem_used_max_store(struct device *dev,
>  	if (init_done(zram)) {
>  		struct zram_meta *meta = zram->meta;
>  		atomic_long_set(&zram->stats.max_used_pages,
> -				zs_get_total_pages(meta->mem_pool));
> +			zpool_get_total_size(meta->mem_pool) >> PAGE_SHIFT);
>  	}
>  	up_read(&zram->init_lock);
>  
> @@ -399,7 +402,7 @@ static ssize_t compact_store(struct device *dev,
>  	}
>  
>  	meta = zram->meta;
> -	zs_compact(meta->mem_pool);
> +	zpool_compact(meta->mem_pool, NULL);

so you don't use that 'compacted' param.


>  	up_read(&zram->init_lock);
>  
>  	return len;
> @@ -436,8 +439,8 @@ static ssize_t mm_stat_show(struct device *dev,
>  
>  	down_read(&zram->init_lock);
>  	if (init_done(zram)) {
> -		mem_used = zs_get_total_pages(zram->meta->mem_pool);
> -		zs_pool_stats(zram->meta->mem_pool, &pool_stats);
> +		mem_used = zpool_get_total_size(zram->meta->mem_pool);
> +		zpool_stats(zram->meta->mem_pool, &pool_stats);
>  	}
>  
>  	orig_size = atomic64_read(&zram->stats.pages_stored);
> @@ -447,7 +450,7 @@ static ssize_t mm_stat_show(struct device *dev,
>  			"%8llu %8llu %8llu %8lu %8ld %8llu %8lu\n",
>  			orig_size << PAGE_SHIFT,
>  			(u64)atomic64_read(&zram->stats.compr_data_size),
> -			mem_used << PAGE_SHIFT,
> +			mem_used,
>  			zram->limit_pages << PAGE_SHIFT,
>  			max_used << PAGE_SHIFT,
>  			(u64)atomic64_read(&zram->stats.zero_pages),
> @@ -492,10 +495,10 @@ static void zram_meta_free(struct zram_meta *meta, u64 disksize)
>  		if (!handle)
>  			continue;
>  
> -		zs_free(meta->mem_pool, handle);
> +		zpool_free(meta->mem_pool, handle);
>  	}
>  
> -	zs_destroy_pool(meta->mem_pool);
> +	zpool_destroy_pool(meta->mem_pool);
>  	vfree(meta->table);
>  	kfree(meta);
>  }
> @@ -515,7 +518,8 @@ static struct zram_meta *zram_meta_alloc(char *pool_name, u64 disksize)
>  		goto out_error;
>  	}
>  
> -	meta->mem_pool = zs_create_pool(pool_name, GFP_NOIO | __GFP_HIGHMEM);
> +	meta->mem_pool = zpool_create_pool(pool_type, pool_name,
> +			GFP_NOIO | __GFP_HIGHMEM, NULL);
>  	if (!meta->mem_pool) {
>  		pr_err("Error creating memory pool\n");
>  		goto out_error;
> @@ -551,7 +555,7 @@ static void zram_free_page(struct zram *zram, size_t index)
>  		return;
>  	}
>  
> -	zs_free(meta->mem_pool, handle);
> +	zpool_free(meta->mem_pool, handle);
>  
>  	atomic64_sub(zram_get_obj_size(meta, index),
>  			&zram->stats.compr_data_size);
> @@ -579,12 +583,12 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
>  		return 0;
>  	}
>  
> -	cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO);
> +	cmem = zpool_map_handle(meta->mem_pool, handle, ZPOOL_MM_RO);
>  	if (size == PAGE_SIZE)
>  		copy_page(mem, cmem);
>  	else
>  		ret = zcomp_decompress(zram->comp, cmem, size, mem);
> -	zs_unmap_object(meta->mem_pool, handle);
> +	zpool_unmap_handle(meta->mem_pool, handle);
>  	bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
>  
>  	/* Should NEVER happen. Return bio error if it does. */
> @@ -718,24 +722,24 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
>  			src = uncmem;
>  	}
>  
> -	handle = zs_malloc(meta->mem_pool, clen);
> -	if (!handle) {
> +	if (zpool_malloc(meta->mem_pool, clen, __GFP_IO | __GFP_NOWARN,

hm, GFP_NOIO and __GFP_IO...

> +			&handle) != 0) {
>  		pr_err("Error allocating memory for compressed page: %u, size=%zu\n",
>  			index, clen);
>  		ret = -ENOMEM;
>  		goto out;
>  	}
>  
> -	alloced_pages = zs_get_total_pages(meta->mem_pool);
> +	alloced_pages = zpool_get_total_size(meta->mem_pool) >> PAGE_SHIFT;
>  	if (zram->limit_pages && alloced_pages > zram->limit_pages) {
> -		zs_free(meta->mem_pool, handle);
> +		zpool_free(meta->mem_pool, handle);
>  		ret = -ENOMEM;
>  		goto out;
>  	}
>  
>  	update_used_max(zram, alloced_pages);
>  
> -	cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO);
> +	cmem = zpool_map_handle(meta->mem_pool, handle, ZPOOL_MM_WO);
>  
>  	if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) {
>  		src = kmap_atomic(page);
> @@ -747,7 +751,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
>  
>  	zcomp_strm_release(zram->comp, zstrm);
>  	zstrm = NULL;
> -	zs_unmap_object(meta->mem_pool, handle);
> +	zpool_unmap_handle(meta->mem_pool, handle);
>  
>  	/*
>  	 * Free memory associated with this sector
> @@ -1457,6 +1461,8 @@ module_param(num_devices, uint, 0);
>  MODULE_PARM_DESC(num_devices, "Number of pre-created zram devices");
>  module_param(max_zpage_size, ulong, 0);
>  MODULE_PARM_DESC(max_zpage_size, "Threshold for storing compressed pages");
> +module_param_named(zpool_type, pool_type, charp, 0444);
> +MODULE_PARM_DESC(zpool_type, "zpool implementation selection (zsmalloc vs zbud)");
>  
>  MODULE_LICENSE("Dual BSD/GPL");
>  MODULE_AUTHOR("Nitin Gupta <ngupta@xxxxxxxxxx>");
> diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
> index 3a29c33..9a64b94 100644
> --- a/drivers/block/zram/zram_drv.h
> +++ b/drivers/block/zram/zram_drv.h
> @@ -16,7 +16,7 @@
>  #define _ZRAM_DRV_H_
>  
>  #include <linux/spinlock.h>
> -#include <linux/zsmalloc.h>
> +#include <linux/zpool.h>
>  
>  #include "zcomp.h"
>  
> @@ -73,7 +73,7 @@ struct zram_stats {
>  
>  struct zram_meta {
>  	struct zram_table_entry *table;
> -	struct zs_pool *mem_pool;
> +	struct zpool *mem_pool;
>  };
>  
>  struct zram {
> -- 
> 1.9.1
> 
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