FTL: Add l2p cache get/set logic

This commit also introduces ranking pages, based on usage for determining the least used
page to be evicted.

Signed-off-by: Kozlowski Mateusz <mateusz.kozlowski@intel.com>
Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
Change-Id: Iaf3812177b61376bb38aa209e4ba8576d784ffb5
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/13354
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Mellanox Build Bot
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>

lib/ftl/ftl_l2p_cache.c

@@ -44,7 +44,7 @@ struct ftl_l2p_page {
 	enum ftl_l2p_page_state state;
 	uint64_t pin_ref_cnt;
 	struct ftl_l2p_cache_page_io_ctx ctx;
-	bool on_rank_list;
+	bool on_lru_list;
 	void *page_buffer;
 	ftl_df_obj_id obj_id;
 };
@@ -149,6 +149,52 @@ ftl_l2p_cache_get_page_all_size(void)
 	return sizeof(struct ftl_l2p_page) + ftl_l2p_cache_get_l1_page_size();
 }
 
+static void
+ftl_l2p_cache_lru_remove_page(struct ftl_l2p_cache *cache, struct ftl_l2p_page *page)
+{
+	assert(page);
+	assert(page->on_lru_list);
+
+	TAILQ_REMOVE(&cache->lru_list, page, list_entry);
+	page->on_lru_list = false;
+}
+
+static void
+ftl_l2p_cache_lru_add_page(struct ftl_l2p_cache *cache, struct ftl_l2p_page *page)
+{
+	assert(page);
+	assert(!page->on_lru_list);
+
+	TAILQ_INSERT_HEAD(&cache->lru_list, page, list_entry);
+
+	page->on_lru_list = true;
+}
+
+static void
+ftl_l2p_cache_lru_promote_page(struct ftl_l2p_cache *cache, struct ftl_l2p_page *page)
+{
+	if (!page->on_lru_list) {
+		return;
+	}
+
+	ftl_l2p_cache_lru_remove_page(cache, page);
+	ftl_l2p_cache_lru_add_page(cache, page);
+}
+
+static inline ftl_addr
+ftl_l2p_cache_get_addr(struct spdk_ftl_dev *dev,
+		       struct ftl_l2p_cache *cache, struct ftl_l2p_page *page, uint64_t lba)
+{
+	return ftl_addr_load(dev, page->page_buffer, lba % cache->lbas_in_page);
+}
+
+static inline void
+ftl_l2p_cache_set_addr(struct spdk_ftl_dev *dev, struct ftl_l2p_cache *cache,
+		       struct ftl_l2p_page *page, uint64_t lba, ftl_addr addr)
+{
+	ftl_addr_store(dev, page->page_buffer, lba % cache->lbas_in_page, addr);
+}
+
 static void *
 _ftl_l2p_cache_init(struct spdk_ftl_dev *dev, size_t addr_size, uint64_t l2p_size)
 {
@@ -181,6 +227,19 @@ fail_l2_md:
 	return NULL;
 }
 
+static struct ftl_l2p_page *
+get_l2p_page_by_df_id(struct ftl_l2p_cache *cache, size_t page_no)
+{
+	struct ftl_l2p_l1_map_entry *me = cache->l2_mapping;
+	ftl_df_obj_id obj_id = me[page_no].page_obj_id;
+
+	if (obj_id != FTL_DF_OBJ_ID_INVALID) {
+		return ftl_mempool_get_df_ptr(cache->l2_ctx_pool, obj_id);
+	}
+
+	return NULL;
+}
+
 int
 ftl_l2p_cache_init(struct spdk_ftl_dev *dev)
 {
@@ -350,6 +409,52 @@ ftl_l2p_cache_halt(struct spdk_ftl_dev *dev)
 	}
 }
 
+static inline struct ftl_l2p_page *
+get_page(struct ftl_l2p_cache *cache, uint64_t lba)
+{
+	return get_l2p_page_by_df_id(cache, lba / cache->lbas_in_page);
+}
+
+static inline bool
+ftl_l2p_cache_running(struct ftl_l2p_cache *cache)
+{
+	return cache->state == L2P_CACHE_RUNNING;
+}
+
+ftl_addr
+ftl_l2p_cache_get(struct spdk_ftl_dev *dev, uint64_t lba)
+{
+	assert(dev->num_lbas > lba);
+	struct ftl_l2p_cache *cache = (struct ftl_l2p_cache *)dev->l2p;
+	struct ftl_l2p_page *page = get_page(cache, lba);
+	ftl_addr addr;
+
+	ftl_bug(!page);
+	assert(ftl_l2p_cache_running(cache));
+	assert(page->pin_ref_cnt);
+
+	ftl_l2p_cache_lru_promote_page(cache, page);
+	addr = ftl_l2p_cache_get_addr(dev, cache, page, lba);
+
+	return addr;
+}
+
+void
+ftl_l2p_cache_set(struct spdk_ftl_dev *dev, uint64_t lba, ftl_addr addr)
+{
+	assert(dev->num_lbas > lba);
+	struct ftl_l2p_cache *cache = (struct ftl_l2p_cache *)dev->l2p;
+	struct ftl_l2p_page *page = get_page(cache, lba);
+
+	ftl_bug(!page);
+	assert(ftl_l2p_cache_running(cache));
+	assert(page->pin_ref_cnt);
+
+	page->updates++;
+	ftl_l2p_cache_lru_promote_page(cache, page);
+	ftl_l2p_cache_set_addr(dev, cache, page, lba, addr);
+}
+
 void
 ftl_l2p_cache_process(struct spdk_ftl_dev *dev)
 {