Illumos #3329, #3330, #3331, #3335

[zfs.git] / module / zfs / space_map.c

diff --git a/module/zfs/space_map.c b/module/zfs/space_map.c
index 9c0cdb6..d99c7c0 100644 (file)
--- a/module/zfs/space_map.c
+++ b/module/zfs/space_map.c
@@ -29,6 +29,23 @@
 #include <sys/zio.h>
 #include <sys/space_map.h>
 
+static kmem_cache_t *space_seg_cache;
+
+void
+space_map_init(void)
+{
+       ASSERT(space_seg_cache == NULL);
+       space_seg_cache = kmem_cache_create("space_seg_cache",
+           sizeof (space_seg_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
+}
+
+void
+space_map_fini(void)
+{
+       kmem_cache_destroy(space_seg_cache);
+       space_seg_cache = NULL;
+}
+
 /*
  * Space map routines.
  * NOTE: caller is responsible for all locking.
@@ -121,7 +138,7 @@ space_map_add(space_map_t *sm, uint64_t start, uint64_t size)
                        avl_remove(sm->sm_pp_root, ss_after);
                }
                ss_after->ss_start = ss_before->ss_start;
-               kmem_free(ss_before, sizeof (*ss_before));
+               kmem_cache_free(space_seg_cache, ss_before);
                ss = ss_after;
        } else if (merge_before) {
                ss_before->ss_end = end;
@@ -134,7 +151,7 @@ space_map_add(space_map_t *sm, uint64_t start, uint64_t size)
                        avl_remove(sm->sm_pp_root, ss_after);
                ss = ss_after;
        } else {
-               ss = kmem_alloc(sizeof (*ss), KM_PUSHPAGE);
+               ss = kmem_cache_alloc(space_seg_cache, KM_PUSHPAGE);
                ss->ss_start = start;
                ss->ss_end = end;
                avl_insert(&sm->sm_root, ss, where);
@@ -181,7 +198,7 @@ space_map_remove(space_map_t *sm, uint64_t start, uint64_t size)
                avl_remove(sm->sm_pp_root, ss);
 
        if (left_over && right_over) {
-               newseg = kmem_alloc(sizeof (*newseg), KM_PUSHPAGE);
+               newseg = kmem_cache_alloc(space_seg_cache, KM_PUSHPAGE);
                newseg->ss_start = end;
                newseg->ss_end = ss->ss_end;
                ss->ss_end = start;
@@ -194,7 +211,7 @@ space_map_remove(space_map_t *sm, uint64_t start, uint64_t size)
                ss->ss_start = end;
        } else {
                avl_remove(&sm->sm_root, ss);
-               kmem_free(ss, sizeof (*ss));
+               kmem_cache_free(space_seg_cache, ss);
                ss = NULL;
        }
 
@@ -234,7 +251,7 @@ space_map_vacate(space_map_t *sm, space_map_func_t *func, space_map_t *mdest)
        while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) {
                if (func != NULL)
                        func(mdest, ss->ss_start, ss->ss_end - ss->ss_start);
-               kmem_free(ss, sizeof (*ss));
+               kmem_cache_free(space_seg_cache, ss);
        }
        sm->sm_space = 0;
 }
@@ -406,7 +423,7 @@ space_map_sync(space_map_t *sm, uint8_t maptype,
        spa_t *spa = dmu_objset_spa(os);
        void *cookie = NULL;
        space_seg_t *ss;
-       uint64_t bufsize, start, size, run_len;
+       uint64_t bufsize, start, size, run_len, delta, sm_space;
        uint64_t *entry, *entry_map, *entry_map_end;
 
        ASSERT(MUTEX_HELD(sm->sm_lock));
@@ -435,11 +452,13 @@ space_map_sync(space_map_t *sm, uint8_t maptype,
            SM_DEBUG_SYNCPASS_ENCODE(spa_sync_pass(spa)) |
            SM_DEBUG_TXG_ENCODE(dmu_tx_get_txg(tx));
 
+       delta = 0;
+       sm_space = sm->sm_space;
        while ((ss = avl_destroy_nodes(&sm->sm_root, &cookie)) != NULL) {
                size = ss->ss_end - ss->ss_start;
                start = (ss->ss_start - sm->sm_start) >> sm->sm_shift;
 
-               sm->sm_space -= size;
+               delta += size;
                size >>= sm->sm_shift;
 
                while (size) {
@@ -461,7 +480,7 @@ space_map_sync(space_map_t *sm, uint8_t maptype,
                        start += run_len;
                        size -= run_len;
                }
-               kmem_free(ss, sizeof (*ss));
+               kmem_cache_free(space_seg_cache, ss);
        }
 
        if (entry != entry_map) {
@@ -473,8 +492,15 @@ space_map_sync(space_map_t *sm, uint8_t maptype,
                smo->smo_objsize += size;
        }
 
+       /*
+        * Ensure that the space_map's accounting wasn't changed
+        * while we were in the middle of writing it out.
+        */
+       VERIFY3U(sm->sm_space, ==, sm_space);
+
        zio_buf_free(entry_map, bufsize);
 
+       sm->sm_space -= delta;
        VERIFY3U(sm->sm_space, ==, 0);
 }