On Tue, Mar 12, 2019 at 12:16:07AM +0000, Roman Gushchin wrote:
> On Fri, Mar 08, 2019 at 03:14:23PM +1100, Tobin C. Harding wrote:
> > Implement functions to migrate objects. This is based on
> > initial code by Matthew Wilcox and was modified to work with
> > slab object migration.
> >
> > Co-developed-by: Christoph Lameter <cl@xxxxxxxxx>
> > Signed-off-by: Tobin C. Harding <tobin@xxxxxxxxxx>
> > ---
> > lib/radix-tree.c | 13 +++++++++++++
> > lib/xarray.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 57 insertions(+)
> >
> > diff --git a/lib/radix-tree.c b/lib/radix-tree.c
> > index 14d51548bea6..9412c2853726 100644
> > --- a/lib/radix-tree.c
> > +++ b/lib/radix-tree.c
> > @@ -1613,6 +1613,17 @@ static int radix_tree_cpu_dead(unsigned int cpu)
> > return 0;
> > }
> >
> > +extern void xa_object_migrate(void *tree_node, int numa_node);
> > +
> > +static void radix_tree_migrate(struct kmem_cache *s, void **objects, int nr,
> > + int node, void *private)
> > +{
> > + int i;
> > +
> > + for (i = 0; i < nr; i++)
> > + xa_object_migrate(objects[i], node);
> > +}
> > +
> > void __init radix_tree_init(void)
> > {
> > int ret;
> > @@ -1627,4 +1638,6 @@ void __init radix_tree_init(void)
> > ret = cpuhp_setup_state_nocalls(CPUHP_RADIX_DEAD, "lib/radix:dead",
> > NULL, radix_tree_cpu_dead);
> > WARN_ON(ret < 0);
> > + kmem_cache_setup_mobility(radix_tree_node_cachep, NULL,
> > + radix_tree_migrate);
> > }
> > diff --git a/lib/xarray.c b/lib/xarray.c
> > index 81c3171ddde9..4f6f17c87769 100644
> > --- a/lib/xarray.c
> > +++ b/lib/xarray.c
> > @@ -1950,6 +1950,50 @@ void xa_destroy(struct xarray *xa)
> > }
> > EXPORT_SYMBOL(xa_destroy);
> >
> > +void xa_object_migrate(struct xa_node *node, int numa_node)
> > +{
> > + struct xarray *xa = READ_ONCE(node->array);
> > + void __rcu **slot;
> > + struct xa_node *new_node;
> > + int i;
> > +
> > + /* Freed or not yet in tree then skip */
> > + if (!xa || xa == XA_FREE_MARK)
> > + return;
>
> XA_FREE_MARK is equal to 0, so the second check is redundant.
>
> #define XA_MARK_0 ((__force xa_mark_t)0U)
> #define XA_MARK_1 ((__force xa_mark_t)1U)
> #define XA_MARK_2 ((__force xa_mark_t)2U)
> #define XA_PRESENT ((__force xa_mark_t)8U)
> #define XA_MARK_MAX XA_MARK_2
> #define XA_FREE_MARK XA_MARK_0
>
> xa_node_free() sets node->array to XA_RCU_FREE, so maybe it's
> what you need. I'm not sure however, Matthew should know better
Cheers, will wait for his input.
> > +
> > + new_node = kmem_cache_alloc_node(radix_tree_node_cachep,
> > + GFP_KERNEL, numa_node);
>
> We need to check here if the allocation was successful.
Woops, bad Tobin. Thanks.
Tobin.
