kern/slab: remove the KMEM_CACHE_NORECLAIM flag

Don't encourage anyone to use non reclaimable pools of resources, it's
a Bad Thing To Do.

3 files changed, 16 insertions, 27 deletions

diff --git a/kern/slab.c b/kern/slab.c
index 5140130..9ccbb43 100644
--- a/kern/slab.c
+++ b/kern/slab.c
@@ -213,17 +213,6 @@
 #endif /* _HOST_BIG_ENDIAN */
 
 /*
- * Cache flags.
- *
- * The flags don't change once set and can be tested without locking.
- */
-#define KMEM_CF_NO_CPU_POOL     0x01    /* CPU pool layer disabled */
-#define KMEM_CF_SLAB_EXTERNAL   0x02    /* Slab data is off slab */
-#define KMEM_CF_NO_RECLAIM      0x04    /* Slabs are not reclaimable */
-#define KMEM_CF_VERIFY          0x08    /* Debugging facilities enabled */
-#define KMEM_CF_DIRECT          0x10    /* No buf-to-slab tree lookup */
-
-/*
  * Options for kmem_cache_alloc_verify().
  */
 #define KMEM_AV_NOCONSTRUCT 0
@@ -445,7 +434,6 @@ static struct kmem_slab * kmem_slab_create(struct kmem_cache *cache,
         return NULL;
 
     if (cache->flags & KMEM_CF_SLAB_EXTERNAL) {
-        assert(!(cache->flags & KMEM_CF_NO_RECLAIM));
         slab = (struct kmem_slab *)kmem_cache_alloc(&kmem_slab_cache);
 
         if (slab == NULL) {
@@ -518,7 +506,6 @@ static void kmem_slab_destroy(struct kmem_slab *slab, struct kmem_cache *cache)
 
     assert(slab->nr_refs == 0);
     assert(slab->first_free != NULL);
-    assert(!(cache->flags & KMEM_CF_NO_RECLAIM));
 
     if (cache->flags & KMEM_CF_VERIFY)
         kmem_slab_destroy_verify(slab, cache);
@@ -786,12 +773,6 @@ void kmem_cache_init(struct kmem_cache *cache, const char *name,
     if (flags & KMEM_CACHE_NOCPUPOOL)
         cache->flags |= KMEM_CF_NO_CPU_POOL;
 
-    if (flags & KMEM_CACHE_NORECLAIM) {
-        assert(slab_free_fn == NULL);
-        flags |= KMEM_CACHE_NOOFFSLAB;
-        cache->flags |= KMEM_CF_NO_RECLAIM;
-    }
-
     if (flags & KMEM_CACHE_VERIFY)
         cache->flags |= KMEM_CF_VERIFY;
 
@@ -907,9 +888,6 @@ static void kmem_cache_reap(struct kmem_cache *cache)
     struct list dead_slabs;
     unsigned long nr_free_slabs;
 
-    if (cache->flags & KMEM_CF_NO_RECLAIM)
-        return;
-
     simple_lock(&cache->lock);
     list_set_head(&dead_slabs, &cache->free_slabs);
     list_init(&cache->free_slabs);
@@ -1507,8 +1485,6 @@ kern_return_t host_slab_info(host_t host, cache_info_array_t *infop,
                          ? CACHE_FLAGS_NO_CPU_POOL : 0)
                         | ((cache->flags & KMEM_CF_SLAB_EXTERNAL)
                            ? CACHE_FLAGS_SLAB_EXTERNAL : 0)
-                        | ((cache->flags & KMEM_CF_NO_RECLAIM)
-                           ? CACHE_FLAGS_NO_RECLAIM : 0)
                         | ((cache->flags & KMEM_CF_VERIFY)
                            ? CACHE_FLAGS_VERIFY : 0)
                         | ((cache->flags & KMEM_CF_DIRECT)
diff --git a/kern/slab.h b/kern/slab.h
index c7be169..bbd9d41 100644
--- a/kern/slab.h
+++ b/kern/slab.h
@@ -155,6 +155,16 @@ typedef void (*kmem_slab_free_fn_t)(vm_offset_t, vm_size_t);
 #define KMEM_CACHE_NAME_SIZE 24
 
 /*
+ * Cache flags.
+ *
+ * The flags don't change once set and can be tested without locking.
+ */
+#define KMEM_CF_NO_CPU_POOL     0x1 /* CPU pool layer disabled */
+#define KMEM_CF_SLAB_EXTERNAL   0x2 /* Slab data is off slab */
+#define KMEM_CF_VERIFY          0x4 /* Debugging facilities enabled */
+#define KMEM_CF_DIRECT          0x8 /* No buf-to-slab tree lookup */
+
+/*
  * Cache of objects.
  *
  * Locking order : cpu_pool -> cache. CPU pools locking is ordered by CPU ID.
@@ -215,12 +225,13 @@ extern vm_map_t kmem_map;
  */
 #define KMEM_CACHE_NOCPUPOOL    0x1 /* Don't use the per-cpu pools */
 #define KMEM_CACHE_NOOFFSLAB    0x2 /* Don't allocate external slab data */
-#define KMEM_CACHE_NORECLAIM    0x4 /* Never give slabs back to their source,
-                                       implies KMEM_CACHE_NOOFFSLAB */
-#define KMEM_CACHE_VERIFY       0x8 /* Use debugging facilities */
+#define KMEM_CACHE_VERIFY       0x4 /* Use debugging facilities */
 
 /*
  * Initialize a cache.
+ *
+ * If a slab allocation/free function pointer is NULL, the default backend
+ * (vm_kmem on the kernel map) is used for the allocation/free action.
  */
 void kmem_cache_init(struct kmem_cache *cache, const char *name,
                      size_t obj_size, size_t align, kmem_cache_ctor_t ctor,
diff --git a/vm/vm_map.c b/vm/vm_map.c
index ae3ce21..4977bff 100644
--- a/vm/vm_map.c
+++ b/vm/vm_map.c
@@ -182,10 +182,12 @@ void vm_map_init(void)
 			NULL, NULL, NULL, 0);
 	kmem_cache_init(&vm_map_entry_cache, "vm_map_entry",
 			sizeof(struct vm_map_entry), 0, NULL, NULL, NULL, 0);
+#if 0
 	kmem_cache_init(&vm_map_kentry_cache, "vm_map_kentry",
 			sizeof(struct vm_map_entry), 0, NULL, kentry_pagealloc,
 			NULL, KMEM_CACHE_NOCPUPOOL | KMEM_CACHE_NOOFFSLAB
 			      | KMEM_CACHE_NORECLAIM);
+#endif
 	kmem_cache_init(&vm_map_copy_cache, "vm_map_copy",
 			sizeof(struct vm_map_copy), 0, NULL, NULL, NULL, 0);