On Tue, Jan 27, 2015 at 09:22:57PM -0500, Sasha Levin wrote:
> Provides a userspace interface to trigger a CMA release.
>
> Usage:
>
> echo [pages] > free
>
> This would provide testing/fuzzing access to the CMA release paths.
>
> Signed-off-by: Sasha Levin <sasha.le...@oracle.com>
> ---
> mm/cma_debug.c | 56
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 56 insertions(+)
>
> diff --git a/mm/cma_debug.c b/mm/cma_debug.c
> index 5bd6863..c29f029 100644
> --- a/mm/cma_debug.c
> +++ b/mm/cma_debug.c
> @@ -39,6 +39,59 @@ static void cma_add_to_cma_mem_list(struct cma *cma,
> struct cma_mem *mem)
> spin_unlock(&cma->mem_head_lock);
> }
>
> +static struct cma_mem *cma_get_entry_from_list(struct cma *cma)
> +{
> + struct cma_mem *mem = NULL;
> +
> + spin_lock(&cma->mem_head_lock);
> + if (!hlist_empty(&cma->mem_head)) {
> + mem = hlist_entry(cma->mem_head.first, struct cma_mem, node);
> + hlist_del_init(&mem->node);
> + }
> + spin_unlock(&cma->mem_head_lock);
> +
> + return mem;
> +}
> +
> +static int cma_free_mem(struct cma *cma, int count)
> +{
> + struct cma_mem *mem = NULL;
> +
> + while (count) {
> + mem = cma_get_entry_from_list(cma);
> + if (mem == NULL)
> + return 0;
> +
> + if (mem->n <= count) {
> + cma_release(cma, mem->p, mem->n);
> + count -= mem->n;
> + kfree(mem);
> + } else if (cma->order_per_bit == 0) {
> + cma_release(cma, mem->p, count);
> + mem->p += count;
> + mem->n -= count;
> + count = 0;
> + cma_add_to_cma_mem_list(cma, mem);
> + } else {
> + cma_add_to_cma_mem_list(cma, mem);
> + break;
> + }
> + }
Hmm... I'm not sure we need to deal with "mem->m < count" case.
It is not suitable for any cma_alloc/release usecase.
And, I'd like to insert some error log to last case rather than
silently ignoring the request.
Thanks.
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