include/linux/nfs_flushd.h

   1 #ifndef NFS_CLUSTER_H
   2 #define NFS_CLUSTER_H
   3
   4
   5
   6 #ifdef __KERNEL__
   7 #include <asm/atomic.h>
   8 #include <linux/nfs_fs_sb.h>
   9
  10 /*
  11  * Counters of total number and pending number of requests.
  12  * When the total number of requests exceeds the soft limit, we start
  13  * flushing out requests. If it exceeds the hard limit, we stall until
  14  * it drops again.
  15  */
  16 #define MAX_REQUEST_SOFT        192
  17 #define MAX_REQUEST_HARD        256
  18
  19 /*
  20  * Maximum number of requests per write cluster.
  21  * 32 requests per cluster account for 128K of data on an intel box.
  22  * Note: it's a good idea to make this number smaller than MAX_REQUEST_SOFT.
  23  *
  24  * For 100Mbps Ethernet, 128 pages (i.e. 256K) per cluster gives much
  25  * better performance.
  26  */
  27 #define REQUEST_HASH_SIZE       16
  28 #define REQUEST_NR(off)         ((off) >> PAGE_CACHE_SHIFT)
  29 #define REQUEST_HASH(ino, off)  (((ino) ^ REQUEST_NR(off)) & (REQUEST_HASH_SIZE - 1))
  30
  31
  32 /*
  33  * Functions
  34  */
  35 extern int              nfs_reqlist_alloc(struct nfs_server *);
  36 extern void             nfs_reqlist_free(struct nfs_server *);
  37 extern int              nfs_reqlist_init(struct nfs_server *);
  38 extern void             nfs_reqlist_exit(struct nfs_server *);
  39 extern void             inode_schedule_scan(struct inode *, unsigned long);
  40 extern void             inode_remove_flushd(struct inode *);
  41 extern void             nfs_wake_flushd(void);
  42
  43 /*
  44  * This is the per-mount writeback cache.
  45  */
  46 struct nfs_reqlist {
  47         atomic_t                nr_requests;
  48         unsigned long           runat;
  49         wait_queue_head_t       request_wait;
  50
  51         /* The async RPC task that is responsible for scanning the
  52          * requests.
  53          */
  54         struct rpc_task         *task;          /* request flush task */
  55
  56         /* Authentication flavor handle for this NFS client */
  57         struct rpc_auth         *auth;
  58
  59         /* The list of all inodes with pending writebacks.  */
  60         struct inode            *inodes;
  61 };
  62
  63 #endif
  64
  65 #endif