Replace a global map->crush_workspace (protected by a global mutex)
with a list of workspaces, up to the number of CPUs + 1.
This is based on a patch from Robin Geuze <robing@xxxxxxxxxxxx>.
Robin and his team have observed a 10-20% increase in IOPS on all
queue depths and lower CPU usage as well on a high-end all-NVMe
100GbE cluster.
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
---
include/linux/ceph/osdmap.h | 14 ++-
include/linux/crush/crush.h | 3 +
net/ceph/osdmap.c | 166 ++++++++++++++++++++++++++++++++----
3 files changed, 166 insertions(+), 17 deletions(-)
diff --git a/include/linux/ceph/osdmap.h b/include/linux/ceph/osdmap.h
index 3f4498fef6ad..cad9acfbc320 100644
--- a/include/linux/ceph/osdmap.h
+++ b/include/linux/ceph/osdmap.h
@@ -137,6 +137,17 @@ int ceph_oid_aprintf(struct ceph_object_id *oid, gfp_t gfp,
const char *fmt, ...);
void ceph_oid_destroy(struct ceph_object_id *oid);
+struct workspace_manager {
+ struct list_head idle_ws;
+ spinlock_t ws_lock;
+ /* Number of free workspaces */
+ int free_ws;
+ /* Total number of allocated workspaces */
+ atomic_t total_ws;
+ /* Waiters for a free workspace */
+ wait_queue_head_t ws_wait;
+};
+
struct ceph_pg_mapping {
struct rb_node node;
struct ceph_pg pgid;
@@ -184,8 +195,7 @@ struct ceph_osdmap {
* the list of osds that store+replicate them. */
struct crush_map *crush;
- struct mutex crush_workspace_mutex;
- void *crush_workspace;
+ struct workspace_manager crush_wsm;
};
static inline bool ceph_osd_exists(struct ceph_osdmap *map, int osd)
diff --git a/include/linux/crush/crush.h b/include/linux/crush/crush.h
index 2f811baf78d2..30dba392b730 100644
--- a/include/linux/crush/crush.h
+++ b/include/linux/crush/crush.h
@@ -346,6 +346,9 @@ struct crush_work_bucket {
struct crush_work {
struct crush_work_bucket **work; /* Per-bucket working store */
+#ifdef __KERNEL__
+ struct list_head item;
+#endif
};
#ifdef __KERNEL__
diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index 96c25f5e064a..fa08c15be0c0 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -964,6 +964,143 @@ static int decode_pool_names(void **p, void *end, struct ceph_osdmap *map)
return -EINVAL;
}
+/*
+ * CRUSH workspaces
+ *
+ * workspace_manager framework borrowed from fs/btrfs/compression.c.
+ * Two simplifications: there is only one type of workspace and there
+ * is always at least one workspace.
+ */
+static struct crush_work *alloc_workspace(const struct crush_map *c)
+{
+ struct crush_work *work;
+ size_t work_size;
+
+ WARN_ON(!c->working_size);
+ work_size = crush_work_size(c, CEPH_PG_MAX_SIZE);
+ dout("%s work_size %zu bytes\n", __func__, work_size);
+
+ work = ceph_kvmalloc(work_size, GFP_NOIO);
+ if (!work)
+ return NULL;
+
+ INIT_LIST_HEAD(&work->item);
+ crush_init_workspace(c, work);
+ return work;
+}
+
+static void free_workspace(struct crush_work *work)
+{
+ WARN_ON(!list_empty(&work->item));
+ kvfree(work);
+}
+
+static void init_workspace_manager(struct workspace_manager *wsm)
+{
+ INIT_LIST_HEAD(&wsm->idle_ws);
+ spin_lock_init(&wsm->ws_lock);
+ atomic_set(&wsm->total_ws, 0);
+ wsm->free_ws = 0;
+ init_waitqueue_head(&wsm->ws_wait);
+}
+
+static void add_initial_workspace(struct workspace_manager *wsm,
+ struct crush_work *work)
+{
+ WARN_ON(!list_empty(&wsm->idle_ws));
+
+ list_add(&work->item, &wsm->idle_ws);
+ atomic_set(&wsm->total_ws, 1);
+ wsm->free_ws = 1;
+}
+
+static void cleanup_workspace_manager(struct workspace_manager *wsm)
+{
+ struct crush_work *work;
+
+ while (!list_empty(&wsm->idle_ws)) {
+ work = list_first_entry(&wsm->idle_ws, struct crush_work,
+ item);
+ list_del_init(&work->item);
+ free_workspace(work);
+ }
+ atomic_set(&wsm->total_ws, 0);
+ wsm->free_ws = 0;
+}
+
+/*
+ * Finds an available workspace or allocates a new one. If it's not
+ * possible to allocate a new one, waits until there is one.
+ */
+static struct crush_work *get_workspace(struct workspace_manager *wsm,
+ const struct crush_map *c)
+{
+ struct crush_work *work;
+ int cpus = num_online_cpus();
+
+again:
+ spin_lock(&wsm->ws_lock);
+ if (!list_empty(&wsm->idle_ws)) {
+ work = list_first_entry(&wsm->idle_ws, struct crush_work,
+ item);
+ list_del_init(&work->item);
+ wsm->free_ws--;
+ spin_unlock(&wsm->ws_lock);
+ return work;
+
+ }
+ if (atomic_read(&wsm->total_ws) > cpus) {
+ DEFINE_WAIT(wait);
+
+ spin_unlock(&wsm->ws_lock);
+ prepare_to_wait(&wsm->ws_wait, &wait, TASK_UNINTERRUPTIBLE);
+ if (atomic_read(&wsm->total_ws) > cpus && !wsm->free_ws)
+ schedule();
+ finish_wait(&wsm->ws_wait, &wait);
+ goto again;
+ }
+ atomic_inc(&wsm->total_ws);
+ spin_unlock(&wsm->ws_lock);
+
+ work = alloc_workspace(c);
+ if (!work) {
+ atomic_dec(&wsm->total_ws);
+ wake_up(&wsm->ws_wait);
+
+ /*
+ * Do not return the error but go back to waiting. We
+ * have the inital workspace and the CRUSH computation
+ * time is bounded so we will get it eventually.
+ */
+ WARN_ON(atomic_read(&wsm->total_ws) < 1);
+ goto again;
+ }
+ return work;
+}
+
+/*
+ * Puts a workspace back on the list or frees it if we have enough
+ * idle ones sitting around.
+ */
+static void put_workspace(struct workspace_manager *wsm,
+ struct crush_work *work)
+{
+ spin_lock(&wsm->ws_lock);
+ if (wsm->free_ws <= num_online_cpus()) {
+ list_add(&work->item, &wsm->idle_ws);
+ wsm->free_ws++;
+ spin_unlock(&wsm->ws_lock);
+ goto wake;
+ }
+ spin_unlock(&wsm->ws_lock);
+
+ free_workspace(work);
+ atomic_dec(&wsm->total_ws);
+wake:
+ if (wq_has_sleeper(&wsm->ws_wait))
+ wake_up(&wsm->ws_wait);
+}
+
/*
* osd map
*/
@@ -981,7 +1118,8 @@ struct ceph_osdmap *ceph_osdmap_alloc(void)
map->primary_temp = RB_ROOT;
map->pg_upmap = RB_ROOT;
map->pg_upmap_items = RB_ROOT;
- mutex_init(&map->crush_workspace_mutex);
+
+ init_workspace_manager(&map->crush_wsm);
return map;
}
@@ -989,8 +1127,11 @@ struct ceph_osdmap *ceph_osdmap_alloc(void)
void ceph_osdmap_destroy(struct ceph_osdmap *map)
{
dout("osdmap_destroy %p\n", map);
+
if (map->crush)
crush_destroy(map->crush);
+ cleanup_workspace_manager(&map->crush_wsm);
+
while (!RB_EMPTY_ROOT(&map->pg_temp)) {
struct ceph_pg_mapping *pg =
rb_entry(rb_first(&map->pg_temp),
@@ -1029,7 +1170,6 @@ void ceph_osdmap_destroy(struct ceph_osdmap *map)
kvfree(map->osd_weight);
kvfree(map->osd_addr);
kvfree(map->osd_primary_affinity);
- kvfree(map->crush_workspace);
kfree(map);
}
@@ -1104,26 +1244,22 @@ static int osdmap_set_max_osd(struct ceph_osdmap *map, u32 max)
static int osdmap_set_crush(struct ceph_osdmap *map, struct crush_map *crush)
{
- void *workspace;
- size_t work_size;
+ struct crush_work *work;
if (IS_ERR(crush))
return PTR_ERR(crush);
- work_size = crush_work_size(crush, CEPH_PG_MAX_SIZE);
- dout("%s work_size %zu bytes\n", __func__, work_size);
- workspace = ceph_kvmalloc(work_size, GFP_NOIO);
- if (!workspace) {
+ work = alloc_workspace(crush);
+ if (!work) {
crush_destroy(crush);
return -ENOMEM;
}
- crush_init_workspace(crush, workspace);
if (map->crush)
crush_destroy(map->crush);
- kvfree(map->crush_workspace);
+ cleanup_workspace_manager(&map->crush_wsm);
map->crush = crush;
- map->crush_workspace = workspace;
+ add_initial_workspace(&map->crush_wsm, work);
return 0;
}
@@ -2322,6 +2458,7 @@ static int do_crush(struct ceph_osdmap *map, int ruleno, int x,
s64 choose_args_index)
{
struct crush_choose_arg_map *arg_map;
+ struct crush_work *work;
int r;
BUG_ON(result_max > CEPH_PG_MAX_SIZE);
@@ -2332,12 +2469,11 @@ static int do_crush(struct ceph_osdmap *map, int ruleno, int x,
arg_map = lookup_choose_arg_map(&map->crush->choose_args,
CEPH_DEFAULT_CHOOSE_ARGS);
- mutex_lock(&map->crush_workspace_mutex);
+ work = get_workspace(&map->crush_wsm, map->crush);
r = crush_do_rule(map->crush, ruleno, x, result, result_max,
- weight, weight_max, map->crush_workspace,
+ weight, weight_max, work,
arg_map ? arg_map->args : NULL);
- mutex_unlock(&map->crush_workspace_mutex);
-
+ put_workspace(&map->crush_wsm, work);
return r;
}
--
2.19.2
