Second Extended Filesystem (ext2) and other improvements (#33)

[lunaix-os.git] / lunaix-os / kernel / bcache.c

diff --git a/lunaix-os/kernel/bcache.c b/lunaix-os/kernel/bcache.c
new file mode 100644 (file)
index 0000000..3190374
--- /dev/null
+++ b/lunaix-os/kernel/bcache.c
@@ -0,0 +1,215 @@
+#include <lunaix/bcache.h>
+#include <lunaix/mm/valloc.h>
+#include <lunaix/spike.h>
+
+static struct lru_zone* bcache_global_lru;
+
+#define lock(bc)  spinlock_acquire(&((bc)->lock))
+#define unlock(bc)  spinlock_release(&((bc)->lock))
+
+static void 
+__evict_internal_locked(struct bcache_node* node)
+{
+    struct bcache* cache;
+
+    cache = node->holder;
+    cache->ops.sync_cached(cache, node->tag, node->data);
+
+    cache->ops.release_on_evict(cache, node->data);
+}
+
+static int 
+__try_evict_bcache(struct lru_node* node)
+{
+    struct bcache_node* bnode;
+    struct bcache* cache;
+    
+    bnode = container_of(node, struct bcache_node, lru_node);
+    cache = bnode->holder;
+    
+    lock(cache);
+
+    if (bnode->refs) {
+        unlock(cache);
+        return false;
+    }
+    
+    __evict_internal_locked(bnode);
+    btrie_remove(&cache->root, bnode->tag);
+    llist_delete(&bnode->objs);
+
+    vfree(bnode);
+
+    unlock(cache);
+
+    return true;
+}
+
+bcache_zone_t
+bcache_create_zone(char* name)
+{
+    return lru_new_zone(name, __try_evict_bcache);
+}
+
+void
+bcache_init_zone(struct bcache* cache, bcache_zone_t lru, unsigned int log_ways, 
+                   int cap, unsigned int blk_size, struct bcache_ops* ops)
+{
+    // TODO handle cap
+    
+    *cache = (struct bcache) {
+        .lru = lru,
+        .ops = *ops,
+        .blksz = blk_size
+    };
+
+    btrie_init(&cache->root, log_ways);
+    llist_init_head(&cache->objs);
+    spinlock_init(&cache->lock);
+}
+
+bcobj_t
+bcache_put_and_ref(struct bcache* cache, unsigned long tag, void* block)
+{
+    struct bcache_node* node;
+
+    lock(cache);
+
+    node = (struct bcache_node*)btrie_get(&cache->root, tag);
+
+    if (node != NULL) {
+        assert(!node->refs);
+        __evict_internal_locked(node);
+        // Now the node is ready to be reused.
+    }
+    else {
+        node = vzalloc(sizeof(*node));
+        btrie_set(&cache->root, tag, node);
+    }
+    
+    *node = (struct bcache_node) {
+        .data = block,
+        .holder = cache,
+        .tag = tag,
+        .refs = 1
+    };
+
+    lru_use_one(cache->lru, &node->lru_node);
+    llist_append(&cache->objs, &node->objs);
+
+    unlock(cache);
+
+    return (bcobj_t)node;
+}
+
+bool
+bcache_tryget(struct bcache* cache, unsigned long tag, bcobj_t* result)
+{
+    struct bcache_node* node;
+
+    lock(cache);
+
+    node = (struct bcache_node*)btrie_get(&cache->root, tag);
+    if (!node) {
+        unlock(cache);
+        *result = NULL;
+
+        return false;
+    }
+
+    node->refs++;
+
+    *result = (bcobj_t)node;
+
+    unlock(cache);
+    
+    return true;
+}
+
+void
+bcache_return(bcobj_t obj)
+{
+    struct bcache_node* node = (struct bcache_node*) obj;
+
+    assert(node->refs);
+
+    // non bisogno bloccare il cache, perche il lru ha la serratura propria.
+    lru_use_one(node->holder->lru, &node->lru_node);
+    node->refs--;
+}
+
+void
+bcache_promote(bcobj_t obj)
+{
+    struct bcache_node* node;
+    
+    node = (struct bcache_node*) obj;
+    assert(node->refs);
+    lru_use_one(node->holder->lru, &node->lru_node);
+}
+
+void
+bcache_evict(struct bcache* cache, unsigned long tag)
+{
+    struct bcache_node* node;
+
+    lock(cache);
+
+    node = (struct bcache_node*)btrie_get(&cache->root, tag);
+    
+    if (!node || node->refs) {
+        unlock(cache);
+        return;
+    }
+
+    __evict_internal_locked(node);
+
+    btrie_remove(&cache->root, tag);
+    lru_remove(cache->lru, &node->lru_node);
+    llist_delete(&node->objs);
+
+    vfree(node);
+
+    unlock(cache);
+}
+
+static void
+bcache_flush_locked(struct bcache* cache)
+{
+    struct bcache_node *pos, *n;
+    llist_for_each(pos, n, &cache->objs, objs) {
+        __evict_internal_locked(pos);
+        btrie_remove(&cache->root, pos->tag);
+        lru_remove(cache->lru, &pos->lru_node);
+        llist_delete(&pos->objs);
+    }
+}
+
+void
+bcache_flush(struct bcache* cache)
+{
+    lock(cache);
+    
+    bcache_flush_locked(cache);
+
+    unlock(cache);
+}
+
+void
+bcache_free(struct bcache* cache)
+{
+    lock(cache);
+    
+    bcache_flush_locked(cache);
+    btrie_release(&cache->root);
+
+    unlock(cache);
+
+    vfree(cache);
+}
+
+void
+bcache_zone_free(bcache_zone_t zone)
+{
+    lru_free_zone(zone);
+}
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