Re: [BUG] Linux 2.6.25-rc2 - Regression from 2.6.24-rc1-git1softlockup while bootup on powerpc

From: KAMEZAWA Hiroyuki
Date: Tue Feb 19 2008 - 03:08:46 EST


On Sun, 17 Feb 2008 20:29:13 +0100
Jens Axboe <jens.axboe@xxxxxxxxxx> wrote:

> It's odd stuff. Could you perhaps try and add some printks to
> block/cfq-iosched.c:call_for_each_cic(), like dumping the 'nr' return
> from radix_tree_gang_lookup() and the pointer value of cics[i] in the
> for() loop after the lookup?
>
I met the same issue on ia64/NUMA box.
seems cisc[]->key is NULL and index for radix_tree_gang_lookup() was always '1'.

Attached patch works well for me,
but I don't know much about cfq. please confirm.

Regards,
-Kame

==
cics[]->key can be NULL.
In that case, cics[]->dead_key has key value.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>

Index: linux-2.6.25-rc2/block/cfq-iosched.c
===================================================================
--- linux-2.6.25-rc2.orig/block/cfq-iosched.c
+++ linux-2.6.25-rc2/block/cfq-iosched.c
@@ -1171,7 +1171,11 @@ call_for_each_cic(struct io_context *ioc
break;

called += nr;
- index = 1 + (unsigned long) cics[nr - 1]->key;
+
+ if (!cics[nr - 1]->key)
+ index = 1 + (unsigned long) cics[nr - 1]->dead_key;
+ else
+ index = 1 + (unsigned long) cics[nr - 1]->key;

for (i = 0; i < nr; i++)
func(ioc, cics[i]);

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