ceph: rewrite msgpool using mempool_t
Since we don't need to maintain large pools of messages, we can just
use the standard mempool_t. We maintain a msgpool 'wrapper' because we
need the mempool_t* in the alloc function, and mempool gives us only
pool_data.
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/msgpool.c b/fs/ceph/msgpool.c
index 030297f..ca03222 100644
--- a/fs/ceph/msgpool.c
+++ b/fs/ceph/msgpool.c
@@ -7,106 +7,43 @@
#include "msgpool.h"
-/*
- * We use msg pools to preallocate memory for messages we expect to
- * receive over the wire, to avoid getting ourselves into OOM
- * conditions at unexpected times. We take use a few different
- * strategies:
- *
- * - for request/response type interactions, we preallocate the
- * memory needed for the response when we generate the request.
- *
- * - for messages we can receive at any time from the MDS, we preallocate
- * a pool of messages we can re-use.
- *
- * - for writeback, we preallocate some number of messages to use for
- * requests and their replies, so that we always make forward
- * progress.
- *
- * The msgpool behaves like a mempool_t, but keeps preallocated
- * ceph_msgs strung together on a list_head instead of using a pointer
- * vector. This avoids vector reallocation when we adjust the number
- * of preallocated items (which happens frequently).
- */
-
-
-/*
- * Allocate or release as necessary to meet our target pool size.
- */
-static int __fill_msgpool(struct ceph_msgpool *pool)
+static void *alloc_fn(gfp_t gfp_mask, void *arg)
{
- struct ceph_msg *msg;
+ struct ceph_msgpool *pool = arg;
+ struct ceph_msg *m;
- while (pool->num < pool->min) {
- dout("fill_msgpool %p %d/%d allocating\n", pool, pool->num,
- pool->min);
- spin_unlock(&pool->lock);
- msg = ceph_msg_new(0, pool->front_len, 0, 0, NULL);
- spin_lock(&pool->lock);
- if (IS_ERR(msg))
- return PTR_ERR(msg);
- msg->pool = pool;
- list_add(&msg->list_head, &pool->msgs);
- pool->num++;
- }
- while (pool->num > pool->min) {
- msg = list_first_entry(&pool->msgs, struct ceph_msg, list_head);
- dout("fill_msgpool %p %d/%d releasing %p\n", pool, pool->num,
- pool->min, msg);
- list_del_init(&msg->list_head);
- pool->num--;
- ceph_msg_kfree(msg);
- }
- return 0;
+ m = ceph_msg_new(0, pool->front_len, 0, 0, NULL);
+ if (IS_ERR(m))
+ return NULL;
+ return m;
+}
+
+static void free_fn(void *element, void *arg)
+{
+ ceph_msg_put(element);
}
int ceph_msgpool_init(struct ceph_msgpool *pool,
- int front_len, int min, bool blocking)
+ int front_len, int size, bool blocking)
{
- int ret;
-
- dout("msgpool_init %p front_len %d min %d\n", pool, front_len, min);
- spin_lock_init(&pool->lock);
pool->front_len = front_len;
- INIT_LIST_HEAD(&pool->msgs);
- pool->num = 0;
- pool->min = min;
- pool->blocking = blocking;
- init_waitqueue_head(&pool->wait);
-
- spin_lock(&pool->lock);
- ret = __fill_msgpool(pool);
- spin_unlock(&pool->lock);
- return ret;
+ pool->pool = mempool_create(size, alloc_fn, free_fn, pool);
+ if (!pool->pool)
+ return -ENOMEM;
+ return 0;
}
void ceph_msgpool_destroy(struct ceph_msgpool *pool)
{
- dout("msgpool_destroy %p\n", pool);
- spin_lock(&pool->lock);
- pool->min = 0;
- __fill_msgpool(pool);
- spin_unlock(&pool->lock);
+ mempool_destroy(pool->pool);
}
-int ceph_msgpool_resv(struct ceph_msgpool *pool, int delta)
+struct ceph_msg *ceph_msgpool_get(struct ceph_msgpool *pool,
+ int front_len)
{
- int ret;
+ if (front_len > pool->front_len) {
+ struct ceph_msg *msg;
- spin_lock(&pool->lock);
- dout("msgpool_resv %p delta %d\n", pool, delta);
- pool->min += delta;
- ret = __fill_msgpool(pool);
- spin_unlock(&pool->lock);
- return ret;
-}
-
-struct ceph_msg *ceph_msgpool_get(struct ceph_msgpool *pool, int front_len)
-{
- wait_queue_t wait;
- struct ceph_msg *msg;
-
- if (front_len && front_len > pool->front_len) {
pr_err("msgpool_get pool %p need front %d, pool size is %d\n",
pool, front_len, pool->front_len);
WARN_ON(1);
@@ -115,72 +52,17 @@
msg = ceph_msg_new(0, front_len, 0, 0, NULL);
if (!IS_ERR(msg))
return msg;
+ return NULL;
}
- if (!front_len)
- front_len = pool->front_len;
-
- if (pool->blocking) {
- /* mempool_t behavior; first try to alloc */
- msg = ceph_msg_new(0, front_len, 0, 0, NULL);
- if (!IS_ERR(msg))
- return msg;
- }
-
- while (1) {
- spin_lock(&pool->lock);
- if (likely(pool->num)) {
- msg = list_entry(pool->msgs.next, struct ceph_msg,
- list_head);
- list_del_init(&msg->list_head);
- pool->num--;
- dout("msgpool_get %p got %p, now %d/%d\n", pool, msg,
- pool->num, pool->min);
- spin_unlock(&pool->lock);
- return msg;
- }
- pr_err("msgpool_get %p now %d/%d, %s\n", pool, pool->num,
- pool->min, pool->blocking ? "waiting" : "may fail");
- spin_unlock(&pool->lock);
-
- if (!pool->blocking) {
- WARN_ON(1);
-
- /* maybe we can allocate it now? */
- msg = ceph_msg_new(0, front_len, 0, 0, NULL);
- if (!IS_ERR(msg))
- return msg;
-
- pr_err("msgpool_get %p empty + alloc failed\n", pool);
- return ERR_PTR(-ENOMEM);
- }
-
- init_wait(&wait);
- prepare_to_wait(&pool->wait, &wait, TASK_UNINTERRUPTIBLE);
- schedule();
- finish_wait(&pool->wait, &wait);
- }
+ return mempool_alloc(pool->pool, GFP_NOFS);
}
void ceph_msgpool_put(struct ceph_msgpool *pool, struct ceph_msg *msg)
{
- spin_lock(&pool->lock);
- if (pool->num < pool->min) {
- /* reset msg front_len; user may have changed it */
- msg->front.iov_len = pool->front_len;
- msg->hdr.front_len = cpu_to_le32(pool->front_len);
+ /* reset msg front_len; user may have changed it */
+ msg->front.iov_len = pool->front_len;
+ msg->hdr.front_len = cpu_to_le32(pool->front_len);
- kref_init(&msg->kref); /* retake a single ref */
- list_add(&msg->list_head, &pool->msgs);
- pool->num++;
- dout("msgpool_put %p reclaim %p, now %d/%d\n", pool, msg,
- pool->num, pool->min);
- spin_unlock(&pool->lock);
- wake_up(&pool->wait);
- } else {
- dout("msgpool_put %p drop %p, at %d/%d\n", pool, msg,
- pool->num, pool->min);
- spin_unlock(&pool->lock);
- ceph_msg_kfree(msg);
- }
+ kref_init(&msg->kref); /* retake single ref */
}
diff --git a/fs/ceph/msgpool.h b/fs/ceph/msgpool.h
index bc834bf..62a61c7 100644
--- a/fs/ceph/msgpool.h
+++ b/fs/ceph/msgpool.h
@@ -1,6 +1,7 @@
#ifndef _FS_CEPH_MSGPOOL
#define _FS_CEPH_MSGPOOL
+#include <linux/mempool.h>
#include "messenger.h"
/*
@@ -8,18 +9,13 @@
* avoid unexpected OOM conditions.
*/
struct ceph_msgpool {
- spinlock_t lock;
+ mempool_t *pool;
int front_len; /* preallocated payload size */
- struct list_head msgs; /* msgs in the pool; each has 1 ref */
- int num, min; /* cur, min # msgs in the pool */
- bool blocking;
- wait_queue_head_t wait;
};
extern int ceph_msgpool_init(struct ceph_msgpool *pool,
int front_len, int size, bool blocking);
extern void ceph_msgpool_destroy(struct ceph_msgpool *pool);
-extern int ceph_msgpool_resv(struct ceph_msgpool *, int delta);
extern struct ceph_msg *ceph_msgpool_get(struct ceph_msgpool *,
int front_len);
extern void ceph_msgpool_put(struct ceph_msgpool *, struct ceph_msg *);