linux/fs/nfs/nfs4session.h
Trond Myklebust 1fa8064429 NFSv4.1: Try to eliminate outliers when updating target_highest_slotid
Look for sudden changes in the first and second derivatives in order
to eliminate outlier changes to target_highest_slotid (which are
due to out-of-order RPC replies).

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-12-06 00:30:53 +01:00

143 lines
3.9 KiB
C

/*
* fs/nfs/nfs4session.h
*
* Copyright (c) 2012 Trond Myklebust <Trond.Myklebust@netapp.com>
*
*/
#ifndef __LINUX_FS_NFS_NFS4SESSION_H
#define __LINUX_FS_NFS_NFS4SESSION_H
/* maximum number of slots to use */
#define NFS4_DEF_SLOT_TABLE_SIZE (16U)
#define NFS4_MAX_SLOT_TABLE (1024U)
#define NFS4_NO_SLOT ((u32)-1)
#if IS_ENABLED(CONFIG_NFS_V4)
/* Sessions slot seqid */
struct nfs4_slot {
struct nfs4_slot_table *table;
struct nfs4_slot *next;
unsigned long generation;
unsigned long renewal_time;
u32 slot_nr;
u32 seq_nr;
};
/* Sessions */
#define SLOT_TABLE_SZ DIV_ROUND_UP(NFS4_MAX_SLOT_TABLE, 8*sizeof(long))
struct nfs4_slot_table {
struct nfs4_session *session; /* Parent session */
struct nfs4_slot *slots; /* seqid per slot */
unsigned long used_slots[SLOT_TABLE_SZ]; /* used/unused bitmap */
spinlock_t slot_tbl_lock;
struct rpc_wait_queue slot_tbl_waitq; /* allocators may wait here */
u32 max_slots; /* # slots in table */
u32 max_slotid; /* Max allowed slotid value */
u32 highest_used_slotid; /* sent to server on each SEQ.
* op for dynamic resizing */
u32 target_highest_slotid; /* Server max_slot target */
u32 server_highest_slotid; /* Server highest slotid */
s32 d_target_highest_slotid; /* Derivative */
s32 d2_target_highest_slotid; /* 2nd derivative */
unsigned long generation; /* Generation counter for
target_highest_slotid */
struct completion complete;
};
/*
* Session related parameters
*/
struct nfs4_session {
struct nfs4_sessionid sess_id;
u32 flags;
unsigned long session_state;
u32 hash_alg;
u32 ssv_len;
/* The fore and back channel */
struct nfs4_channel_attrs fc_attrs;
struct nfs4_slot_table fc_slot_table;
struct nfs4_channel_attrs bc_attrs;
struct nfs4_slot_table bc_slot_table;
struct nfs_client *clp;
/* Create session arguments */
unsigned int fc_target_max_rqst_sz;
unsigned int fc_target_max_resp_sz;
};
enum nfs4_session_state {
NFS4_SESSION_INITING,
NFS4_SESSION_DRAINING,
};
#if defined(CONFIG_NFS_V4_1)
extern struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl);
extern void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot);
extern void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,
u32 target_highest_slotid);
extern void nfs41_update_target_slotid(struct nfs4_slot_table *tbl,
struct nfs4_slot *slot,
struct nfs4_sequence_res *res);
extern int nfs4_setup_session_slot_tables(struct nfs4_session *ses);
extern struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp);
extern void nfs4_destroy_session(struct nfs4_session *session);
extern int nfs4_init_session(struct nfs_server *server);
extern int nfs4_init_ds_session(struct nfs_client *, unsigned long);
extern void nfs4_session_drain_complete(struct nfs4_session *session,
struct nfs4_slot_table *tbl);
static inline bool nfs4_session_draining(struct nfs4_session *session)
{
return !!test_bit(NFS4_SESSION_DRAINING, &session->session_state);
}
bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
struct nfs4_slot *slot);
void nfs41_wake_slot_table(struct nfs4_slot_table *tbl);
/*
* Determine if sessions are in use.
*/
static inline int nfs4_has_session(const struct nfs_client *clp)
{
if (clp->cl_session)
return 1;
return 0;
}
static inline int nfs4_has_persistent_session(const struct nfs_client *clp)
{
if (nfs4_has_session(clp))
return (clp->cl_session->flags & SESSION4_PERSIST);
return 0;
}
#else /* defined(CONFIG_NFS_V4_1) */
static inline int nfs4_init_session(struct nfs_server *server)
{
return 0;
}
/*
* Determine if sessions are in use.
*/
static inline int nfs4_has_session(const struct nfs_client *clp)
{
return 0;
}
static inline int nfs4_has_persistent_session(const struct nfs_client *clp)
{
return 0;
}
#endif /* defined(CONFIG_NFS_V4_1) */
#endif /* IS_ENABLED(CONFIG_NFS_V4) */
#endif /* __LINUX_FS_NFS_NFS4SESSION_H */