So hi, LinuxRaid
I've just installed a software-RAID 5 on my Alpha (miata) Workstation 500au with Kernel 2.6.0-test11. The RAID is made of 4 Western Digital 250Gb HDs on a promise-ata-133tx2.
The initial raidstart and mke2fs worked fine. After the initial sync, a clean boot and a new raidstart, the /proc/mdstat reported that the drive was at "resync" (/var/log/messages says that "raid array is not clean").
The problem is, the resync was blocking the /dev/md0. So, when I did a 'mount /dev/md0', it blocked until the resync was done (and it was a looong time for a nearly 1TB RAID).
Looking through driver/md code I've realized that md_do_sync() was the real devil. After a few diffs with 2.4.23 code I've realized that at the speed limiter part of the function, the old "current->nice = " lines were deleted.
After a few more search (and looking through LXR) at /fs/jffs2/background.c and /net/bluetooth/bnep/core.c I've realized that some people have changed "current->nice =" statements to "set_user_nice(current,...)" ones.
Done that. The RAID worked just fine (still resyncing at boot, not fully tested yet) but don't block mounts anymore (btw, mount returns a lot faster than with 2.4.23).
Since I'm no kernel (nor RAID) expert (first post here, btw), just wandering if I did something really stupid or not.
Also, is this an Alpha-only issue? Or a 2.6.0 issue?
Anyway, here follows the patch for what I've done.
thanks for the attention.
Fernando Serboncini
--- linux-2.6.0-test11/drivers/md/md.c 2003-11-26 18:43:29.000000000 -0200
+++ linux/drivers/md/md.c 2003-12-10 23:29:33.000000000 -0200
@@ -3290,6 +3290,8 @@
currspeed =
(j-mddev->resync_mark_cnt)/2/((jiffies-mddev->resync_mark)/HZ +1) +1; if (currspeed > sysctl_speed_limit_min) {
+ set_user_nice(current,19);
+
if ((currspeed > sysctl_speed_limit_max) ||
!is_mddev_idle(mddev)) {
current->state = TASK_INTERRUPTIBLE;
@@ -3297,6 +3299,8 @@
goto repeat;
}
}
+ else
+ set_user_nice(current,-20);
}
printk(KERN_INFO "md: md%d: sync done.\n",mdidx(mddev));
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