[PATCH] md: fix is_mddev_idle calculation now that disk/sector accounting happens...

[linux-beck.git] / drivers / md / md.c

diff --git a/drivers/md/md.c b/drivers/md/md.c
index f3fed662f32ea603dbe76625369ea8ffaf24672f..78c7418478d63e86f55127026d227bfae18e94a3 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3846,11 +3846,20 @@ static int is_mddev_idle(mddev_t *mddev)
                curr_events = disk_stat_read(disk, sectors[0]) + 
                                disk_stat_read(disk, sectors[1]) - 
                                atomic_read(&disk->sync_io);
-               /* Allow some slack between valud of curr_events and last_events,
-                * as there are some uninteresting races.
+               /* The difference between curr_events and last_events
+                * will be affected by any new non-sync IO (making
+                * curr_events bigger) and any difference in the amount of
+                * in-flight syncio (making current_events bigger or smaller)
+                * The amount in-flight is currently limited to
+                * 32*64K in raid1/10 and 256*PAGE_SIZE in raid5/6
+                * which is at most 4096 sectors.
+                * These numbers are fairly fragile and should be made
+                * more robust, probably by enforcing the
+                * 'window size' that md_do_sync sort-of uses.
+                *
                 * Note: the following is an unsigned comparison.
                 */
-               if ((curr_events - rdev->last_events + 32) > 64) {
+               if ((curr_events - rdev->last_events + 4096) > 8192) {
                        rdev->last_events = curr_events;
                        idle = 0;
                }
@@ -4109,7 +4118,7 @@ static void md_do_sync(mddev_t *mddev)
                if (currspeed > sysctl_speed_limit_min) {
                        if ((currspeed > sysctl_speed_limit_max) ||
                                        !is_mddev_idle(mddev)) {
-                               msleep(250);
+                               msleep(500);
                                goto repeat;
                        }
                }