zsmalloc: require GFP in zs_malloc()

Pass GFP flags to zs_malloc() instead of using a fixed mask supplied to
zs_create_pool(), so we can be more flexible, but, more importantly, we
need this to switch zram to per-cpu compression streams -- zram will try
to allocate handle with preemption disabled in a fast path and switch to
a slow path (using different gfp mask) if the fast one has failed.

Apart from that, this also align zs_malloc() interface with zspool/zbud.

[sergey.senozhatsky@gmail.com: pass GFP flags to zs_malloc() instead of using a fixed mask]
Link: http://lkml.kernel.org/r/20160429150942.GA637@swordfish
Link: http://lkml.kernel.org/r/20160429150942.GA637@swordfish
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 370c2f7..b09acdb 100644 (file)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -514,7 +514,7 @@ 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 = zs_create_pool(pool_name);
        if (!meta->mem_pool) {
                pr_err("Error creating memory pool\n");
                goto out_error;
@@ -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..57a8e98 100644 (file)
--- a/include/linux/zsmalloc.h
+++ b/include/linux/zsmalloc.h
@@ -41,10 +41,10 @@ struct zs_pool_stats {
 
 struct zs_pool;
 
-struct zs_pool *zs_create_pool(const char *name, gfp_t flags);
+struct zs_pool *zs_create_pool(const char *name);
 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 ae288c9..aba39a2 100644 (file)
--- 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)
@@ -324,7 +323,12 @@ static void *zs_zpool_create(const char *name, gfp_t gfp,
                             const struct zpool_ops *zpool_ops,
                             struct zpool *zpool)
 {
-       return zs_create_pool(name, gfp);
+       /*
+        * Ignore global gfp flags: zs_malloc() may be invoked from
+        * different contexts and its caller must provide a valid
+        * gfp mask.
+        */
+       return zs_create_pool(name);
 }
 
 static void zs_zpool_destroy(void *pool)
@@ -335,7 +339,7 @@ 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 +1395,7 @@ 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 +1404,7 @@ 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 +1417,7 @@ 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;
@@ -1878,7 +1882,7 @@ static int zs_register_shrinker(struct zs_pool *pool)
  * On success, a pointer to the newly created pool is returned,
  * otherwise NULL.
  */
-struct zs_pool *zs_create_pool(const char *name, gfp_t flags)
+struct zs_pool *zs_create_pool(const char *name)
 {
        int i;
        struct zs_pool *pool;
@@ -1948,8 +1952,6 @@ struct zs_pool *zs_create_pool(const char *name, gfp_t flags)
                prev_class = class;
        }
 
-       pool->flags = flags;
-
        if (zs_pool_stat_create(pool, name))
                goto err;