Add struct zs_ops with a evict() callback function. Add documentation
to zs_free() function clarifying that it cannot be called with a
zs_pool handle after that handle has been successfully evicted;
since evict calls into a function provided by the zs_pool creator,
the creator is therefore responsible for ensuring this requirement.
This is required to implement zsmalloc shrinking.
Signed-off-by: Dan Streetman <ddstreet@xxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 2 +-
include/linux/zsmalloc.h | 6 +++++-
mm/zsmalloc.c | 26 ++++++++++++++++++++++++--
3 files changed, 30 insertions(+), 4 deletions(-)
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index bc20fe1..31ba9c7 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -328,7 +328,7 @@ static struct zram_meta *zram_meta_alloc(u64 disksize)
goto free_meta;
}
- meta->mem_pool = zs_create_pool(GFP_NOIO | __GFP_HIGHMEM);
+ meta->mem_pool = zs_create_pool(GFP_NOIO | __GFP_HIGHMEM, NULL);
if (!meta->mem_pool) {
pr_err("Error creating memory pool\n");
goto free_table;
diff --git a/include/linux/zsmalloc.h b/include/linux/zsmalloc.h
index 05c2147..2c341d4 100644
--- a/include/linux/zsmalloc.h
+++ b/include/linux/zsmalloc.h
@@ -36,7 +36,11 @@ enum zs_mapmode {
struct zs_pool;
-struct zs_pool *zs_create_pool(gfp_t flags);
+struct zs_ops {
+ int (*evict)(struct zs_pool *pool, unsigned long handle);
+};
+
+struct zs_pool *zs_create_pool(gfp_t flags, struct zs_ops *ops);
void zs_destroy_pool(struct zs_pool *pool);
unsigned long zs_malloc(struct zs_pool *pool, size_t size);
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index a2e417b..3dc7dae 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -221,6 +221,8 @@ struct zs_pool {
gfp_t flags; /* allocation flags used when growing pool */
atomic_long_t pages_allocated;
+
+ struct zs_ops *ops;
};
/*
@@ -256,9 +258,18 @@ static enum fullness_group lru_fg[] = {
#ifdef CONFIG_ZPOOL
+static int zs_zpool_evict(struct zs_pool *pool, unsigned long handle)
+{
+ return zpool_evict(pool, handle);
+}
+
+static struct zs_ops zs_zpool_ops = {
+ .evict = zs_zpool_evict
+};
+
static void *zs_zpool_create(gfp_t gfp, struct zpool_ops *zpool_ops)
{
- return zs_create_pool(gfp);
+ return zs_create_pool(gfp, &zs_zpool_ops);
}
static void zs_zpool_destroy(void *pool)
@@ -1019,7 +1030,7 @@ fail:
* On success, a pointer to the newly created pool is returned,
* otherwise NULL.
*/
-struct zs_pool *zs_create_pool(gfp_t flags)
+struct zs_pool *zs_create_pool(gfp_t flags, struct zs_ops *ops)
{
int i, ovhd_size;
struct zs_pool *pool;
@@ -1046,6 +1057,7 @@ struct zs_pool *zs_create_pool(gfp_t flags)
}
pool->flags = flags;
+ pool->ops = ops;
return pool;
}
@@ -1130,6 +1142,16 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size)
}
EXPORT_SYMBOL_GPL(zs_malloc);
+/**
+ * zs_free - Free the handle from this pool.
+ * @pool: pool containing the handle
+ * @obj: the handle to free
+ *
+ * The caller must provide a valid handle that is contained
+ * in the provided pool. The caller must ensure this is
+ * not called after evict() has returned successfully for the
+ * handle.
+ */
void zs_free(struct zs_pool *pool, unsigned long obj)
{
struct page *first_page, *f_page;
--
1.8.3.1
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