[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <alpine.DEB.2.00.1101051108520.14761@router.home>
Date: Wed, 5 Jan 2011 11:10:47 -0600 (CST)
From: Christoph Lameter <cl@...ux.com>
To: David Rientjes <rientjes@...gle.com>
cc: Pekka Enberg <penberg@...nel.org>, linux-kernel@...r.kernel.org,
Bart Van Assche <bart.vanassche@...il.com>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH] slub: Fix sysfs circular locking dependency
How about this solution? In the common case of kernels without hotplug
support there will be no locking at all.
Subject: slub: Avoid use of slub_lock in show_slab_objects()
The purpose of the locking is to prevent removal and additions
of nodes when statistics are gathered for a slab cache. So we
need to avoid racing with memory hotplug functionality.
It is enough to take the memory hotplug locks there instead
of the slub_lock.
Signed-off-by: Christoph Lameter <cl@...ux.com>
---
mm/slub.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2011-01-05 09:55:34.000000000 -0600
+++ linux-2.6/mm/slub.c 2011-01-05 09:56:27.000000000 -0600
@@ -3821,7 +3821,7 @@ static ssize_t show_slab_objects(struct
}
}
- down_read(&slub_lock);
+ lock_memory_hotplug();
#ifdef CONFIG_SLUB_DEBUG
if (flags & SO_ALL) {
for_each_node_state(node, N_NORMAL_MEMORY) {
@@ -3862,7 +3862,7 @@ static ssize_t show_slab_objects(struct
x += sprintf(buf + x, " N%d=%lu",
node, nodes[node]);
#endif
- up_read(&slub_lock);
+ unlock_memory_hotplug();
kfree(nodes);
return x + sprintf(buf + x, "\n");
}
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists