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Diffstat (limited to 'ipc/mqueue.c')
-rw-r--r--ipc/mqueue.c104
1 files changed, 81 insertions, 23 deletions
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index af1692556c52..8ce57691e7b6 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -69,6 +69,7 @@ struct mqueue_inode_info {
wait_queue_head_t wait_q;
struct rb_root msg_tree;
+ struct posix_msg_tree_node *node_cache;
struct mq_attr attr;
struct sigevent notify;
@@ -134,15 +135,20 @@ static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
else
p = &(*p)->rb_right;
}
- leaf = kzalloc(sizeof(*leaf), GFP_ATOMIC);
- if (!leaf)
- return -ENOMEM;
- rb_init_node(&leaf->rb_node);
- INIT_LIST_HEAD(&leaf->msg_list);
+ if (info->node_cache) {
+ leaf = info->node_cache;
+ info->node_cache = NULL;
+ } else {
+ leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
+ if (!leaf)
+ return -ENOMEM;
+ rb_init_node(&leaf->rb_node);
+ INIT_LIST_HEAD(&leaf->msg_list);
+ info->qsize += sizeof(*leaf);
+ }
leaf->priority = msg->m_type;
rb_link_node(&leaf->rb_node, parent, p);
rb_insert_color(&leaf->rb_node, &info->msg_tree);
- info->qsize += sizeof(struct posix_msg_tree_node);
insert_msg:
info->attr.mq_curmsgs++;
info->qsize += msg->m_ts;
@@ -177,13 +183,17 @@ try_again:
return NULL;
}
leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
- if (list_empty(&leaf->msg_list)) {
+ if (unlikely(list_empty(&leaf->msg_list))) {
pr_warn_once("Inconsistency in POSIX message queue, "
"empty leaf node but we haven't implemented "
"lazy leaf delete!\n");
rb_erase(&leaf->rb_node, &info->msg_tree);
- info->qsize -= sizeof(struct posix_msg_tree_node);
- kfree(leaf);
+ if (info->node_cache) {
+ info->qsize -= sizeof(*leaf);
+ kfree(leaf);
+ } else {
+ info->node_cache = leaf;
+ }
goto try_again;
} else {
msg = list_first_entry(&leaf->msg_list,
@@ -191,8 +201,12 @@ try_again:
list_del(&msg->m_list);
if (list_empty(&leaf->msg_list)) {
rb_erase(&leaf->rb_node, &info->msg_tree);
- info->qsize -= sizeof(struct posix_msg_tree_node);
- kfree(leaf);
+ if (info->node_cache) {
+ info->qsize -= sizeof(*leaf);
+ kfree(leaf);
+ } else {
+ info->node_cache = leaf;
+ }
}
}
info->attr.mq_curmsgs--;
@@ -235,6 +249,7 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
info->qsize = 0;
info->user = NULL; /* set when all is ok */
info->msg_tree = RB_ROOT;
+ info->node_cache = NULL;
memset(&info->attr, 0, sizeof(info->attr));
info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
ipc_ns->mq_msg_default);
@@ -367,6 +382,7 @@ static void mqueue_evict_inode(struct inode *inode)
spin_lock(&info->lock);
while ((msg = msg_get(info)) != NULL)
free_msg(msg);
+ kfree(info->node_cache);
spin_unlock(&info->lock);
/* Total amount of bytes accounted for the mqueue */
@@ -964,7 +980,8 @@ SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
struct mqueue_inode_info *info;
ktime_t expires, *timeout = NULL;
struct timespec ts;
- int ret;
+ struct posix_msg_tree_node *new_leaf = NULL;
+ int ret = 0;
if (u_abs_timeout) {
int res = prepare_timeout(u_abs_timeout, &expires, &ts);
@@ -1012,39 +1029,60 @@ SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
msg_ptr->m_ts = msg_len;
msg_ptr->m_type = msg_prio;
+ /*
+ * msg_insert really wants us to have a valid, spare node struct so
+ * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
+ * fall back to that if necessary.
+ */
+ if (!info->node_cache)
+ new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
+
spin_lock(&info->lock);
+ if (!info->node_cache && new_leaf) {
+ /* Save our speculative allocation into the cache */
+ rb_init_node(&new_leaf->rb_node);
+ INIT_LIST_HEAD(&new_leaf->msg_list);
+ info->node_cache = new_leaf;
+ info->qsize += sizeof(*new_leaf);
+ new_leaf = NULL;
+ } else {
+ kfree(new_leaf);
+ }
+
if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
if (filp->f_flags & O_NONBLOCK) {
- spin_unlock(&info->lock);
ret = -EAGAIN;
} else {
wait.task = current;
wait.msg = (void *) msg_ptr;
wait.state = STATE_NONE;
ret = wq_sleep(info, SEND, timeout, &wait);
+ /*
+ * wq_sleep must be called with info->lock held, and
+ * returns with the lock released
+ */
+ goto out_free;
}
- if (ret < 0)
- free_msg(msg_ptr);
} else {
receiver = wq_get_first_waiter(info, RECV);
if (receiver) {
pipelined_send(info, msg_ptr, receiver);
} else {
/* adds message to the queue */
- if (msg_insert(msg_ptr, info)) {
- free_msg(msg_ptr);
- ret = -ENOMEM;
- spin_unlock(&info->lock);
- goto out_fput;
- }
+ ret = msg_insert(msg_ptr, info);
+ if (ret)
+ goto out_unlock;
__do_notify(info);
}
inode->i_atime = inode->i_mtime = inode->i_ctime =
CURRENT_TIME;
- spin_unlock(&info->lock);
- ret = 0;
}
+out_unlock:
+ spin_unlock(&info->lock);
+out_free:
+ if (ret)
+ free_msg(msg_ptr);
out_fput:
fput(filp);
out:
@@ -1063,6 +1101,7 @@ SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
struct ext_wait_queue wait;
ktime_t expires, *timeout = NULL;
struct timespec ts;
+ struct posix_msg_tree_node *new_leaf = NULL;
if (u_abs_timeout) {
int res = prepare_timeout(u_abs_timeout, &expires, &ts);
@@ -1098,7 +1137,26 @@ SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
goto out_fput;
}
+ /*
+ * msg_insert really wants us to have a valid, spare node struct so
+ * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
+ * fall back to that if necessary.
+ */
+ if (!info->node_cache)
+ new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
+
spin_lock(&info->lock);
+
+ if (!info->node_cache && new_leaf) {
+ /* Save our speculative allocation into the cache */
+ rb_init_node(&new_leaf->rb_node);
+ INIT_LIST_HEAD(&new_leaf->msg_list);
+ info->node_cache = new_leaf;
+ info->qsize += sizeof(*new_leaf);
+ } else {
+ kfree(new_leaf);
+ }
+
if (info->attr.mq_curmsgs == 0) {
if (filp->f_flags & O_NONBLOCK) {
spin_unlock(&info->lock);

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