Re: [PATCH] lib: fix lock initialization in region allocation benchmark

From: Liam R. Howlett

Date: Tue Sep 15 2026 - 11:33:50 EST


On 26/09/11 11:52AM, Yury Norov wrote:
> The Maple Tree benchmark uses MTREE_INIT() for a stack-allocated tree.
> Its static spinlock initializer leaves lockdep to use the lock address
> as the class key. Since the address is on the stack, the first allocation
> triggers "INFO: trying to register non-static key" and disables lockdep.
>
> The IDA benchmark has the same problem through IDA_INIT(), but runs after
> Maple Tree and therefore encounters an already disabled lockdep.
>
> Use mt_init_flags() and ida_init() to initialize the locks with persistent
> lock-class keys. Keep initialization outside the timed allocation paths.
>
> Fixes: f4806cc63cc6 ("lib: test bitmap vs IDA vs Maple Tree performance for region allocations")
> Closes: https://lore.kernel.org/oe-lkp/202609101106.771b567e-lkp@xxxxxxxxx
> Signed-off-by: Yury Norov <ynorov@xxxxxxxxxx>

Acked-by: Liam R. Howlett (Oracle) <liam@xxxxxxxxxxxxx>

> ---
> lib/region_alloc_benchmark.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/lib/region_alloc_benchmark.c b/lib/region_alloc_benchmark.c
> index e88b4cf55c62..a644f3d5431a 100644
> --- a/lib/region_alloc_benchmark.c
> +++ b/lib/region_alloc_benchmark.c
> @@ -78,11 +78,13 @@ static size_t __init ida_size(unsigned long nr_ids)
>
> static unsigned long __init benchmark_ida(unsigned long cap)
> {
> - struct ida ida = IDA_INIT(ida);
> + struct ida ida;
> unsigned long cnt, idx, off, nr_ids = 0;
> ktime_t alloc_time, free_time;
> int id = -ENOSPC;
>
> + ida_init(&ida);
> +
> alloc_time = ktime_get();
> for (cnt = 0; cnt <= cap; cnt++) {
> for (off = 0; off < reg_sz[cnt]; off++) {
> @@ -125,12 +127,14 @@ static unsigned long __init benchmark_ida(unsigned long cap)
>
> static unsigned long __init benchmark_maple_tree(unsigned long cap)
> {
> - struct maple_tree mt = MTREE_INIT(mt, MT_FLAGS_ALLOC_RANGE);
> + struct maple_tree mt;
> unsigned long cnt, idx;
> ktime_t alloc_time, free_time;
> size_t sz;
> int ret;
>
> + mt_init_flags(&mt, MT_FLAGS_ALLOC_RANGE);
> +
> alloc_time = ktime_get();
> for (cnt = 0; cnt <= cap; cnt++) {
> ret = mtree_alloc_range(&mt, &idx, xa_mk_value(cnt + 1),
> --
> 2.53.0
>
>
> --
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