src/patches/suse-2.6.27.25/patches.suse/dm-mpath-tracking-nr-bytes

   1 From: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
   2 Subject: dm-mpath: interface change for service-time dynamic load balancer
   3 References: FATE#303862,FATE#302108
   4
   5 This patch changes path selector interfaces for service-time oriented
   6 dynamic load balancer.
   7
   8 To calculate the service time for an incoming I/O correctly,
   9 the load balancer needs the size of the incoming I/O when selecting
  10 the next path.
  11
  12
  13 Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
  14 Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
  15 Signed-off-by: Hannes Reinecke <hare@suse.de>
  16
  17 ---
  18  drivers/md/dm-least-pending.c |    4 ++--
  19  drivers/md/dm-mpath.c         |   27 ++++++++++++++++-----------
  20  drivers/md/dm-path-selector.h |    9 ++++++---
  21  drivers/md/dm-queue-length.c  |    8 +++++---
  22  drivers/md/dm-round-robin.c   |    2 +-
  23  5 files changed, 30 insertions(+), 20 deletions(-)
  24
  25 --- a/drivers/md/dm-least-pending.c
  26 +++ b/drivers/md/dm-least-pending.c
  27 @@ -172,7 +172,7 @@ static int lpp_reinstate_path(struct pat
  28  }
  29
  30  static struct dm_path *lpp_select_path(struct path_selector *ps,
  31 -                                       unsigned *repeat_count)
  32 +                                       unsigned *repeat_count, size_t nr_bytes)
  33  {
  34         struct selector *s = ps->context;
  35         struct path_info *pi, *next, *least_io_path = NULL;
  36 @@ -199,7 +199,7 @@ static struct dm_path *lpp_select_path(s
  37         return least_io_path->path;
  38  }
  39
  40 -static int lpp_end_io(struct path_selector *ps, struct dm_path *path)
  41 +static int lpp_end_io(struct path_selector *ps, struct dm_path *path, size_t nr_bytes)
  42  {
  43         struct path_info *pi = NULL;
  44
  45 --- a/drivers/md/dm-mpath.c
  46 +++ b/drivers/md/dm-mpath.c
  47 @@ -99,6 +99,7 @@ struct multipath {
  48   */
  49  struct dm_mpath_io {
  50         struct pgpath *pgpath;
  51 +       size_t nr_bytes;
  52  };
  53
  54  typedef int (*action_fn) (struct pgpath *pgpath);
  55 @@ -246,11 +247,12 @@ static void __switch_pg(struct multipath
  56         m->pg_init_count = 0;
  57  }
  58
  59 -static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg)
  60 +static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg,
  61 +                              size_t nr_bytes)
  62  {
  63         struct dm_path *path;
  64
  65 -       path = pg->ps.type->select_path(&pg->ps, &m->repeat_count);
  66 +       path = pg->ps.type->select_path(&pg->ps, &m->repeat_count, nr_bytes);
  67         if (!path)
  68                 return -ENXIO;
  69
  70 @@ -262,7 +264,7 @@ static int __choose_path_in_pg(struct mu
  71         return 0;
  72  }
  73
  74 -static void __choose_pgpath(struct multipath *m)
  75 +static void __choose_pgpath(struct multipath *m, size_t nr_bytes)
  76  {
  77         struct priority_group *pg;
  78         unsigned bypassed = 1;
  79 @@ -274,12 +276,12 @@ static void __choose_pgpath(struct multi
  80         if (m->next_pg) {
  81                 pg = m->next_pg;
  82                 m->next_pg = NULL;
  83 -               if (!__choose_path_in_pg(m, pg))
  84 +               if (!__choose_path_in_pg(m, pg, nr_bytes))
  85                         return;
  86         }
  87
  88         /* Don't change PG until it has no remaining paths */
  89 -       if (m->current_pg && !__choose_path_in_pg(m, m->current_pg))
  90 +       if (m->current_pg && !__choose_path_in_pg(m, m->current_pg, nr_bytes))
  91                 return;
  92
  93         /*
  94 @@ -291,7 +293,7 @@ static void __choose_pgpath(struct multi
  95                 list_for_each_entry(pg, &m->priority_groups, list) {
  96                         if (pg->bypassed == bypassed)
  97                                 continue;
  98 -                       if (!__choose_path_in_pg(m, pg))
  99 +                       if (!__choose_path_in_pg(m, pg, nr_bytes))
 100                                 return;
 101                 }
 102         } while (bypassed--);
 103 @@ -322,6 +324,7 @@ static int map_io(struct multipath *m, s
 104                   struct dm_mpath_io *mpio, unsigned was_queued)
 105  {
 106         int r = DM_MAPIO_REMAPPED;
 107 +       size_t nr_bytes = blk_rq_bytes(clone);
 108         unsigned long flags;
 109         struct pgpath *pgpath;
 110         struct block_device *bdev;
 111 @@ -331,7 +334,7 @@ static int map_io(struct multipath *m, s
 112         /* Do we need to select a new pgpath? */
 113         if (!m->current_pgpath ||
 114             (!m->queue_io && (m->repeat_count && --m->repeat_count == 0)))
 115 -               __choose_pgpath(m);
 116 +               __choose_pgpath(m, nr_bytes);
 117
 118         pgpath = m->current_pgpath;
 119
 120 @@ -358,9 +361,11 @@ static int map_io(struct multipath *m, s
 121                 r = -EIO;       /* Failed */
 122
 123         mpio->pgpath = pgpath;
 124 +       mpio->nr_bytes = nr_bytes;
 125
 126         if (r == DM_MAPIO_REMAPPED && pgpath->pg->ps.type->start_io)
 127 -               pgpath->pg->ps.type->start_io(&pgpath->pg->ps, &pgpath->path);
 128 +               pgpath->pg->ps.type->start_io(&pgpath->pg->ps, &pgpath->path,
 129 +                                             nr_bytes);
 130
 131         spin_unlock_irqrestore(&m->lock, flags);
 132
 133 @@ -440,7 +445,7 @@ static void process_queued_ios(struct wo
 134                 goto out;
 135
 136         if (!m->current_pgpath)
 137 -               __choose_pgpath(m);
 138 +               __choose_pgpath(m, 1 << 19); /* Assume 512 KB */
 139
 140         pgpath = m->current_pgpath;
 141
 142 @@ -1193,7 +1198,7 @@ static int multipath_end_io(struct dm_ta
 143         if (pgpath) {
 144                 ps = &pgpath->pg->ps;
 145                 if (ps->type->end_io)
 146 -                       ps->type->end_io(ps, &pgpath->path);
 147 +                       ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes);
 148         }
 149         mempool_free(mpio, m->mpio_pool);
 150
 151 @@ -1412,7 +1417,7 @@ static int multipath_ioctl(struct dm_tar
 152         spin_lock_irqsave(&m->lock, flags);
 153
 154         if (!m->current_pgpath)
 155 -               __choose_pgpath(m);
 156 +               __choose_pgpath(m, 1 << 19); /* Assume 512KB */
 157
 158         if (m->current_pgpath) {
 159                 bdev = m->current_pgpath->path.dev->bdev;
 160 --- a/drivers/md/dm-path-selector.h
 161 +++ b/drivers/md/dm-path-selector.h
 162 @@ -56,7 +56,8 @@ struct path_selector_type {
 163          * the path fails.
 164          */
 165         struct dm_path *(*select_path) (struct path_selector *ps,
 166 -                                    unsigned *repeat_count);
 167 +                                       unsigned *repeat_count,
 168 +                                       size_t nr_bytes);
 169
 170         /*
 171          * Notify the selector that a path has failed.
 172 @@ -75,8 +76,10 @@ struct path_selector_type {
 173         int (*status) (struct path_selector *ps, struct dm_path *path,
 174                        status_type_t type, char *result, unsigned int maxlen);
 175
 176 -       int (*start_io) (struct path_selector *ps, struct dm_path *path);
 177 -       int (*end_io) (struct path_selector *ps, struct dm_path *path);
 178 +       int (*start_io) (struct path_selector *ps, struct dm_path *path,
 179 +                        size_t nr_bytes);
 180 +       int (*end_io) (struct path_selector *ps, struct dm_path *path,
 181 +                      size_t nr_bytes);
 182  };
 183
 184  /* Register a path selector */
 185 --- a/drivers/md/dm-queue-length.c
 186 +++ b/drivers/md/dm-queue-length.c
 187 @@ -142,7 +142,7 @@ static inline int ql_compare_qlen(struct
 188  }
 189
 190  static struct dm_path *ql_select_path(struct path_selector *ps,
 191 -                                     unsigned *repeat_count)
 192 +                                     unsigned *repeat_count, size_t nr_bytes)
 193  {
 194         struct selector *s = (struct selector *) ps->context;
 195         struct path_info *cpi = NULL, *spi = NULL;
 196 @@ -166,7 +166,8 @@ static struct dm_path *ql_select_path(st
 197         return spi ? spi->path : NULL;
 198  }
 199
 200 -static int ql_start_io(struct path_selector *ps, struct dm_path *path)
 201 +static int ql_start_io(struct path_selector *ps, struct dm_path *path,
 202 +                      size_t nr_bytes)
 203  {
 204         struct path_info *pi = path->pscontext;
 205
 206 @@ -175,7 +176,8 @@ static int ql_start_io(struct path_selec
 207         return 0;
 208  }
 209
 210 -static int ql_end_io(struct path_selector *ps, struct dm_path *path)
 211 +static int ql_end_io(struct path_selector *ps, struct dm_path *path,
 212 +                    size_t nr_bytes)
 213  {
 214         struct path_info *pi = path->pscontext;
 215
 216 --- a/drivers/md/dm-round-robin.c
 217 +++ b/drivers/md/dm-round-robin.c
 218 @@ -160,7 +160,7 @@ static int rr_reinstate_path(struct path
 219  }
 220
 221  static struct dm_path *rr_select_path(struct path_selector *ps,
 222 -                                  unsigned *repeat_count)
 223 +                                     unsigned *repeat_count, size_t nr_bytes)
 224  {
 225         struct selector *s = (struct selector *) ps->context;
 226         struct path_info *pi = NULL;