Messages in this thread | | | Date | Wed, 5 Jan 2011 20:26:08 +0200 | Subject | Re: [PATCH] slub: Fix sysfs circular locking dependency | From | Pekka Enberg <> |
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On Wed, Jan 5, 2011 at 7:10 PM, Christoph Lameter <cl@linux.com> wrote: > 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@linux.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"); > }
Makes sense. Bart, does this fix the problem for you? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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