linux-kernel - Re: [RFC PATCH 4/4] XArray: test: Increase split order test range in check

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Message-ID: <E3AB23B6-9B6C-432C-BD92-27520ADA0739@nvidia.com>
Date: Sun, 07 Dec 2025 22:32:18 -0500
From: Zi Yan <ziy@...dia.com>
To: Ackerley Tng <ackerleytng@...gle.com>
Cc: willy@...radead.org, akpm@...ux-foundation.org,
 linux-fsdevel@...r.kernel.org, linux-mm@...ck.org,
 linux-kernel@...r.kernel.org, david@...hat.com, michael.roth@....com,
 vannapurve@...gle.com
Subject: Re: [RFC PATCH 4/4] XArray: test: Increase split order test range in
 check_split()

On 17 Nov 2025, at 17:47, Ackerley Tng wrote:

> Expand the range of order values for check_split_1() from 2 *
> XA_CHUNK_SHIFT to 4 * XA_CHUNK_SHIFT to test splitting beyond 2 levels.
>
> Separate the loops for check_split_1() and check_split_2() calls, since
> xas_try_split() does not yet support splitting beyond 2 levels.

xas_try_split() is designed to only split at most 1 level. It is used
for non-uniform split, which always splits a folio from order N to order N-1.

>
> Signed-off-by: Ackerley Tng <ackerleytng@...gle.com>
> ---
>  lib/test_xarray.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/lib/test_xarray.c b/lib/test_xarray.c
> index 42626fb4dc0e..fbdf647e4ef8 100644
> --- a/lib/test_xarray.c
> +++ b/lib/test_xarray.c
> @@ -1905,12 +1905,16 @@ static noinline void check_split(struct xarray *xa)
>
>  	XA_BUG_ON(xa, !xa_empty(xa));
>
> -	for (order = 1; order < 2 * XA_CHUNK_SHIFT; order++) {
> +	for (order = 1; order < 4 * XA_CHUNK_SHIFT; order++) {
>  		for (new_order = 0; new_order < order; new_order++) {
>  			check_split_1(xa, 0, order, new_order);
>  			check_split_1(xa, 1UL << order, order, new_order);
>  			check_split_1(xa, 3UL << order, order, new_order);
> +		}
> +	}
>
> +	for (order = 1; order < 2 * XA_CHUNK_SHIFT; order++) {
> +		for (new_order = 0; new_order < order; new_order++) {
>  			check_split_2(xa, 0, order, new_order);
>  			check_split_2(xa, 1UL << order, order, new_order);
>  			check_split_2(xa, 3UL << order, order, new_order);
> --
> 2.52.0.rc1.455.g30608eb744-goog


--
Best Regards,
Yan, Zi