include/sys/mmp.h

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * This file and its contents are supplied under the terms of the
   5  * Common Development and Distribution License ("CDDL"), version 1.0.
   6  * You may only use this file in accordance with the terms of version
   7  * 1.0 of the CDDL.
   8  *
   9  * A full copy of the text of the CDDL should have accompanied this
  10  * source.  A copy of the CDDL is also available via the Internet at
  11  * http://www.illumos.org/license/CDDL.
  12  *
  13  * CDDL HEADER END
  14  */
  15 /*
  16  * Copyright (C) 2017 by Lawrence Livermore National Security, LLC.
  17  */
  18
  19 #ifndef _SYS_MMP_H
  20 #define _SYS_MMP_H
  21
  22 #include <sys/spa.h>
  23 #include <sys/zfs_context.h>
  24 #include <sys/uberblock_impl.h>
  25
  26 #ifdef  __cplusplus
  27 extern "C" {
  28 #endif
  29
  30 #define MMP_MIN_INTERVAL                100     /* ms */
  31 #define MMP_DEFAULT_INTERVAL            1000    /* ms */
  32 #define MMP_DEFAULT_IMPORT_INTERVALS    20
  33 #define MMP_DEFAULT_FAIL_INTERVALS      10
  34 #define MMP_MIN_FAIL_INTERVALS          2       /* min if != 0 */
  35 #define MMP_IMPORT_SAFETY_FACTOR        200     /* pct */
  36 #define MMP_INTERVAL_OK(interval)       MAX(interval, MMP_MIN_INTERVAL)
  37 #define MMP_FAIL_INTVS_OK(fails)        (fails == 0 ? 0 : MAX(fails, \
  38                                             MMP_MIN_FAIL_INTERVALS))
  39
  40 typedef struct mmp_thread {
  41         kmutex_t        mmp_thread_lock; /* protect thread mgmt fields */
  42         kcondvar_t      mmp_thread_cv;
  43         kthread_t       *mmp_thread;
  44         uint8_t         mmp_thread_exiting;
  45         kmutex_t        mmp_io_lock;    /* protect below */
  46         hrtime_t        mmp_last_write; /* last successful MMP write */
  47         uint64_t        mmp_delay;      /* decaying avg ns between MMP writes */
  48         uberblock_t     mmp_ub;         /* last ub written by sync */
  49         zio_t           *mmp_zio_root;  /* root of mmp write zios */
  50         uint64_t        mmp_kstat_id;   /* unique id for next MMP write kstat */
  51         int             mmp_skip_error; /* reason for last skipped write */
  52         vdev_t          *mmp_last_leaf; /* last mmp write sent here */
  53         uint64_t        mmp_leaf_last_gen;      /* last mmp write sent here */
  54         uint32_t        mmp_seq;        /* intra-second update counter */
  55 } mmp_thread_t;
  56
  57
  58 extern void mmp_init(struct spa *spa);
  59 extern void mmp_fini(struct spa *spa);
  60 extern void mmp_thread_start(struct spa *spa);
  61 extern void mmp_thread_stop(struct spa *spa);
  62 extern void mmp_update_uberblock(struct spa *spa, struct uberblock *ub);
  63 extern void mmp_signal_all_threads(void);
  64
  65 /* Global tuning */
  66 extern int param_set_multihost_interval(ZFS_MODULE_PARAM_ARGS);
  67 extern ulong_t zfs_multihost_interval;
  68 extern uint_t zfs_multihost_fail_intervals;
  69 extern uint_t zfs_multihost_import_intervals;
  70
  71 #ifdef  __cplusplus
  72 }
  73 #endif
  74
  75 #endif  /* _SYS_MMP_H */