alistair23-linux/include/linux/ceph/msgpool.h
Ilya Dryomov 0d9c1ab3be libceph: preallocate message data items
Currently message data items are allocated with ceph_msg_data_create()
in setup_request_data() inside send_request().  send_request() has never
been allowed to fail, so each allocation is followed by a BUG_ON:

  data = ceph_msg_data_create(...);
  BUG_ON(!data);

It's been this way since support for multiple message data items was
added in commit 6644ed7b7e ("libceph: make message data be a pointer")
in 3.10.

There is no reason to delay the allocation of message data items until
the last possible moment and we certainly don't need a linked list of
them as they are only ever appended to the end and never erased.  Make
ceph_msg_new2() take max_data_items and adapt the rest of the code.

Reported-by: Jerry Lee <leisurelysw24@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2018-10-22 10:28:22 +02:00

28 lines
811 B
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _FS_CEPH_MSGPOOL
#define _FS_CEPH_MSGPOOL
#include <linux/mempool.h>
/*
* we use memory pools for preallocating messages we may receive, to
* avoid unexpected OOM conditions.
*/
struct ceph_msgpool {
const char *name;
mempool_t *pool;
int type; /* preallocated message type */
int front_len; /* preallocated payload size */
int max_data_items;
};
int ceph_msgpool_init(struct ceph_msgpool *pool, int type,
int front_len, int max_data_items, int size,
const char *name);
extern void ceph_msgpool_destroy(struct ceph_msgpool *pool);
struct ceph_msg *ceph_msgpool_get(struct ceph_msgpool *pool, int front_len,
int max_data_items);
extern void ceph_msgpool_put(struct ceph_msgpool *, struct ceph_msg *);
#endif