On Tue, Apr 02, 2019 at 06:25:30PM +0200, Uladzislau Rezki (Sony) wrote:
> This macro adds some debug code to check that the augment tree
> is maintained correctly, meaning that every node contains valid
> subtree_max_size value.
>
> By default this option is set to 0 and not active. It requires
> recompilation of the kernel to activate it. Set to 1, compile
> the kernel.
>
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
> ---
> mm/vmalloc.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 53 insertions(+)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 3adbad3fb6c1..1449a8c43aa2 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -322,6 +322,8 @@ unsigned long vmalloc_to_pfn(const void *vmalloc_addr)
> EXPORT_SYMBOL(vmalloc_to_pfn);
>
> /*** Global kva allocator ***/
> +#define DEBUG_AUGMENT_PROPAGATE_CHECK 0
> +
> #define VM_LAZY_FREE 0x02
> #define VM_VM_AREA 0x04
>
> @@ -544,6 +546,53 @@ __unlink_va(struct vmap_area *va, struct rb_root *root)
> }
> }
>
> +#if DEBUG_AUGMENT_PROPAGATE_CHECK
> +static void
> +augment_tree_propagate_do_check(struct rb_node *n)
> +{
> + struct vmap_area *va;
> + struct rb_node *node;
> + unsigned long size;
> + bool found = false;
> +
> + if (n == NULL)
> + return;
> +
> + va = rb_entry(n, struct vmap_area, rb_node);
> + size = va->subtree_max_size;
> + node = n;
> +
> + while (node) {
> + va = rb_entry(node, struct vmap_area, rb_node);
> +
> + if (get_subtree_max_size(node->rb_left) == size) {
> + node = node->rb_left;
> + } else {
> + if (__va_size(va) == size) {
> + found = true;
> + break;
> + }
> +
> + node = node->rb_right;
> + }
> + }
> +
> + if (!found) {
> + va = rb_entry(n, struct vmap_area, rb_node);
> + pr_emerg("tree is corrupted: %lu, %lu\n",
> + __va_size(va), va->subtree_max_size);
> + }
> +
> + augment_tree_propagate_do_check(n->rb_left);
> + augment_tree_propagate_do_check(n->rb_right);
> +}
> +
> +static void augment_tree_propagate_from_check(void)
Why do you need this intermediate function?
Other than that looks good to me, please free to use
Reviewed-by: Roman Gushchin <guro@xxxxxx>
Thank you!
