lustre/kernel_patches/patches/md-rebuild-policy.patch

   1 diff -pur linux-2.6.18-53.orig/drivers/md/md.c linux-2.6.18-53/drivers/md/md.c
   2 --- linux-2.6.18-53.orig/drivers/md/md.c        2008-02-13 17:34:25.000000000 +0800
   3 +++ linux-2.6.18-53/drivers/md/md.c     2008-02-13 17:39:28.000000000 +0800
   4 @@ -90,6 +90,8 @@ static void md_print_devices(void);
   5
   6  static int sysctl_speed_limit_min = 1000;
   7  static int sysctl_speed_limit_max = 200000;
   8 +static int sysctl_rebuild_window_size = 256;
   9 +static int sysctl_disk_idle_size = 4096;
  10  static inline int speed_min(mddev_t *mddev)
  11  {
  12         return mddev->sync_speed_min ?
  13 @@ -121,6 +123,22 @@ static ctl_table raid_table[] = {
  14                 .mode           = S_IRUGO|S_IWUSR,
  15                 .proc_handler   = &proc_dointvec,
  16         },
  17 +       {
  18 +               .ctl_name       = DEV_RAID_REBUILD_WINDOW,
  19 +               .procname       = "rebuild_window_size",
  20 +               .data           = &sysctl_rebuild_window_size,
  21 +               .maxlen         = sizeof(int),
  22 +               .mode           = S_IRUGO|S_IWUSR,
  23 +               .proc_handler   = &proc_dointvec,
  24 +       },
  25 +       {
  26 +               .ctl_name       = DEV_RAID_DISK_IDLE_SIZE,
  27 +               .procname       = "disk_idle_size",
  28 +               .data           = &sysctl_disk_idle_size,
  29 +               .maxlen         = sizeof(int),
  30 +               .mode           = S_IRUGO|S_IWUSR,
  31 +               .proc_handler   = &proc_dointvec,
  32 +       },
  33         { .ctl_name = 0 }
  34  };
  35
  36 @@ -4980,14 +4998,15 @@ static int is_mddev_idle(mddev_t *mddev)
  37         mdk_rdev_t * rdev;
  38         struct list_head *tmp;
  39         int idle;
  40 -       unsigned long curr_events;
  41 +       unsigned long rw, sync;
  42
  43         idle = 1;
  44         ITERATE_RDEV(mddev,rdev,tmp) {
  45                 struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
  46 -               curr_events = disk_stat_read(disk, sectors[0]) +
  47 -                               disk_stat_read(disk, sectors[1]) -
  48 -                               atomic_read(&disk->sync_io);
  49 +
  50 +               rw = disk_stat_read(disk, sectors[READ])+disk_stat_read(disk, sectors[WRITE]);
  51 +               sync = atomic_read(&disk->sync_io);
  52 +
  53                 /* The difference between curr_events and last_events
  54                  * will be affected by any new non-sync IO (making
  55                  * curr_events bigger) and any difference in the amount of
  56 @@ -5001,9 +5020,9 @@ static int is_mddev_idle(mddev_t *mddev)
  57                  *
  58                  * Note: the following is an unsigned comparison.
  59                  */
  60 -               if ((curr_events - rdev->last_events + 4096) > 8192) {
  61 -                       rdev->last_events = curr_events;
  62 +               if (rw - rdev->last_events > sync + sysctl_disk_idle_size) {
  63                         idle = 0;
  64 +                       rdev->last_events = rw - sync;
  65                 }
  66         }
  67         return idle;
  68 @@ -5069,8 +5088,7 @@ static DECLARE_WAIT_QUEUE_HEAD(resync_wa
  69  void md_do_sync(mddev_t *mddev)
  70  {
  71         mddev_t *mddev2;
  72 -       unsigned int currspeed = 0,
  73 -                window;
  74 +       unsigned int currspeed = 0;
  75         sector_t max_sectors,j, io_sectors;
  76         unsigned long mark[SYNC_MARKS];
  77         sector_t mark_cnt[SYNC_MARKS];
  78 @@ -5190,9 +5208,8 @@ void md_do_sync(mddev_t *mddev)
  79         /*
  80          * Tune reconstruction:
  81          */
  82 -       window = 32*(PAGE_SIZE/512);
  83         printk(KERN_INFO "md: using %dk window, over a total of %llu blocks.\n",
  84 -               window/2,(unsigned long long) max_sectors/2);
  85 +               sysctl_rebuild_window_size/2,(unsigned long long) max_sectors/2);
  86
  87         atomic_set(&mddev->recovery_active, 0);
  88         init_waitqueue_head(&mddev->recovery_wait);
  89 @@ -5230,7 +5247,7 @@ void md_do_sync(mddev_t *mddev)
  90                          */
  91                         md_new_event(mddev);
  92
  93 -               if (last_check + window > io_sectors || j == max_sectors)
  94 +               if (last_check + sysctl_rebuild_window_size > io_sectors || j == max_sectors)
  95                         continue;
  96
  97                 last_check = io_sectors;
  98 @@ -5251,7 +5268,6 @@ void md_do_sync(mddev_t *mddev)
  99                         last_mark = next;
 100                 }
 101
 102 -
 103                 if (kthread_should_stop()) {
 104                         /*
 105                          * got a signal, exit.
 106 @@ -5275,10 +5291,16 @@ void md_do_sync(mddev_t *mddev)
 107
 108                 currspeed = ((unsigned long)(io_sectors-mddev->resync_mark_cnt))/2
 109                         /((jiffies-mddev->resync_mark)/HZ +1) +1;
 110 -
 111                 if (currspeed > speed_min(mddev)) {
 112                         if ((currspeed > speed_max(mddev)) ||
 113                                         !is_mddev_idle(mddev)) {
 114 +                               static unsigned long next_report;
 115 +                               if (time_after(jiffies, next_report)) {
 116 +                                       printk(KERN_INFO "md: rebuild %s throttled due to IO\n",
 117 +                                               mdname(mddev));
 118 +                                       /* once per 10 minutes */
 119 +                                       next_report = jiffies + 600 * HZ;
 120 +                               }
 121                                 msleep(500);
 122                                 goto repeat;
 123                         }
 124 diff -pur linux-2.6.18-53.orig/include/linux/sysctl.h linux-2.6.18-53/include/linux/sysctl.h
 125 --- linux-2.6.18-53.orig/include/linux/sysctl.h 2008-02-13 17:35:25.000000000 +0800
 126 +++ linux-2.6.18-53/include/linux/sysctl.h      2008-02-13 17:36:22.000000000 +0800
 127 @@ -903,7 +903,9 @@ enum {
 128  /* /proc/sys/dev/raid */
 129  enum {
 130         DEV_RAID_SPEED_LIMIT_MIN=1,
 131 -       DEV_RAID_SPEED_LIMIT_MAX=2
 132 +       DEV_RAID_SPEED_LIMIT_MAX=2,
 133 +       DEV_RAID_REBUILD_WINDOW=3,
 134 +       DEV_RAID_DISK_IDLE_SIZE=4
 135  };
 136
 137  /* /proc/sys/dev/parport/default */