On Fri, Aug 02, 2024 at 04:58:22PM -0700, Shakeel Butt wrote:
> #define MEM_CGROUP_ID_MAX ((1UL << MEM_CGROUP_ID_SHIFT) - 1)
> static DEFINE_IDR(mem_cgroup_idr);
> +static DEFINE_SPINLOCK(memcg_idr_lock);
> +
> +static int mem_cgroup_alloc_id(void)
> +{
> + int ret;
> +
> + idr_preload(GFP_KERNEL);
> + spin_lock(&memcg_idr_lock);
> + ret = idr_alloc(&mem_cgroup_idr, NULL, 1, MEM_CGROUP_ID_MAX + 1,
> + GFP_NOWAIT);
> + spin_unlock(&memcg_idr_lock);
> + idr_preload_end();
> + return ret;
> +}
You know, this works much better as an xarray:
static int mem_cgroup_alloc_id(void)
{
u32 id;
int ret;
ret = xa_alloc(&mem_cgroup_ids, &id, XA_LIMIT(1, MEM_CGROUP_ID_MAX),
GFP_KERNEL);
if (ret < 0)
return ret;
return id;
}
No messing around with preloading, the spinlock is built in and the MAX
works the way you want it to.
