Hello Neil,
On Friday 07 December 2007 03:10:37 Neil Brown wrote:
> On Thursday December 6, bs@xxxxxxxxx wrote:
> > Hello,
> >
> > here is the second version of the patch. With this version also on
> > setting /sys/block/*/md/sync_force_parallel the sync_thread is woken up.
> > Though, I still don't understand why md_wakeup_thread() is not working.
>
> Could give a little more detail on why you want this? When do you
> want multiple arrays on the same device to sync at the same time?
> What exactly is the hardware like?
I did describe it in my first mail, I guess you just missed this one. So I'm
pasting this part here:
On Monday 03 December 2007 14:37:03 Bernd Schubert wrote:
> Hello Neil,
>
>
> on doing software-raid over some Infortrend hardware raid boxes, we can
> easily bring a single cpu to 100%, while the hardware-raid boxes are still
> only utilized for 50% or less.
> So we are using *several* software raids instead of only one. However, for
> us it then also doesn't make sense to have a resync for only one of the
> md-raids. Below is a patch to force parallel resync for specified md-sets
> via sysfs.
> This still leaves a problem, though. If a resync starts before settings
> this parameter, I don't know how to wake up the sleeping resync-thread. Any
> ideas?
>
>
> md threads generally run for a little while to perform some task, then
> stop and wait to be needed again. md_wakeup_thread says "you are
> needed again".
>
> The resync/recovery thread is a bit different. It just run md_do_sync
> once. md_wakeup_thread is not really meaningful in that context.
>
> What you want is:
> wake_up(&resync_wait);
>
> that will get any thread that is waiting for some other array to
> resync to wake up and see if something needs to be done.
Ah thanks a lot! Now I understand. What about this?
Signed-off-by: Bernd Schubert <bs@xxxxxxxxx>
Index: linux-2.6.22/drivers/md/md.c
===================================================================
--- linux-2.6.22.orig/drivers/md/md.c 2007-12-06 19:51:55.000000000 +0100
+++ linux-2.6.22/drivers/md/md.c 2007-12-07 12:07:47.000000000 +0100
@@ -74,6 +74,8 @@ static DEFINE_SPINLOCK(pers_lock);
static void md_print_devices(void);
+static DECLARE_WAIT_QUEUE_HEAD(resync_wait);
+
#define MD_BUG(x...) { printk("md: bug in file %s, line %d\n", __FILE__,
__LINE__); md_print_devices(); }
/*
@@ -2843,6 +2845,34 @@ __ATTR(sync_speed_max, S_IRUGO|S_IWUSR,
static ssize_t
+sync_force_parallel_show(mddev_t *mddev, char *page)
+{
+ return sprintf(page, "%d\n", mddev->parallel_resync);
+}
+
+static ssize_t
+sync_force_parallel_store(mddev_t *mddev, const char *buf, size_t len)
+{
+ char *e;
+ unsigned long n = simple_strtoul(buf, &e, 10);
+
+ if (!*buf || (*e && *e != '\n') || (n != 0 && n != 1))
+ return -EINVAL;
+
+ mddev->parallel_resync = n;
+
+ if (mddev->sync_thread) {
+ wake_up(&resync_wait);
+ }
+ return len;
+}
+
+/* force parallel resync, even with shared block devices */
+static struct md_sysfs_entry md_sync_force_parallel =
+__ATTR(sync_force_parallel, S_IRUGO|S_IWUSR,
+ sync_force_parallel_show, sync_force_parallel_store);
+
+static ssize_t
sync_speed_show(mddev_t *mddev, char *page)
{
unsigned long resync, dt, db;
@@ -2980,6 +3010,7 @@ static struct attribute *md_redundancy_a
&md_sync_min.attr,
&md_sync_max.attr,
&md_sync_speed.attr,
+ &md_sync_force_parallel.attr,
&md_sync_completed.attr,
&md_suspend_lo.attr,
&md_suspend_hi.attr,
@@ -5199,8 +5230,6 @@ void md_allow_write(mddev_t *mddev)
}
EXPORT_SYMBOL_GPL(md_allow_write);
-static DECLARE_WAIT_QUEUE_HEAD(resync_wait);
-
#define SYNC_MARKS 10
#define SYNC_MARK_STEP (3*HZ)
void md_do_sync(mddev_t *mddev)
@@ -5264,8 +5293,9 @@ void md_do_sync(mddev_t *mddev)
ITERATE_MDDEV(mddev2,tmp) {
if (mddev2 == mddev)
continue;
- if (mddev2->curr_resync &&
- match_mddev_units(mddev,mddev2)) {
+ if (!mddev->parallel_resync
+ && mddev2->curr_resync
+ && match_mddev_units(mddev,mddev2)) {
DEFINE_WAIT(wq);
if (mddev < mddev2 && mddev->curr_resync == 2) {
/* arbitrarily yield */
Index: linux-2.6.22/include/linux/raid/md_k.h
===================================================================
--- linux-2.6.22.orig/include/linux/raid/md_k.h 2007-12-06 19:51:55.000000000
+0100
+++ linux-2.6.22/include/linux/raid/md_k.h 2007-12-06 19:52:33.000000000 +0100
@@ -170,6 +170,9 @@ struct mddev_s
int sync_speed_min;
int sync_speed_max;
+ /* resync even though the same disks are shared among md-devices */
+ int parallel_resync;
+
int ok_start_degraded;
/* recovery/resync flags
* NEEDED: we might need to start a resync/recover
--
Bernd Schubert
Q-Leap Networks GmbH
-
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
