2022-04-30 17:28:38

by Muchun Song

Subject: [PATCH v9 3/4] mm: hugetlb_vmemmap: use kstrtobool for hugetlb_vmemmap param parsing

Use kstrtobool rather than open coding "on" and "off" parsing in
mm/hugetlb_vmemmap.c, which is more powerful to handle all kinds
of parameters like 'Yy1Nn0' or [oO][NnFf] for "on" and "off".

Signed-off-by: Muchun Song <[email protected]>
---
Documentation/admin-guide/kernel-parameters.txt | 6 +++---
mm/hugetlb_vmemmap.c | 10 +++++-----
2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 308da668bbb1..43b8385073ad 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1703,10 +1703,10 @@
enabled.
Allows heavy hugetlb users to free up some more
memory (7 * PAGE_SIZE for each 2MB hugetlb page).
- Format: { on | off (default) }
+ Format: { [oO][Nn]/Y/y/1 | [oO][Ff]/N/n/0 (default) }

- on: enable the feature
- off: disable the feature
+ [oO][Nn]/Y/y/1: enable the feature
+ [oO][Ff]/N/n/0: disable the feature

Built with CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON=y,
the default is on.
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index 6254bb2d4ae5..cc4ec752ec16 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -28,15 +28,15 @@ EXPORT_SYMBOL(hugetlb_optimize_vmemmap_key);

static int __init hugetlb_vmemmap_early_param(char *buf)
{
- if (!buf)
+ bool enable;
+
+ if (kstrtobool(buf, &enable))
return -EINVAL;

- if (!strcmp(buf, "on"))
+ if (enable)
static_branch_enable(&hugetlb_optimize_vmemmap_key);
- else if (!strcmp(buf, "off"))
- static_branch_disable(&hugetlb_optimize_vmemmap_key);
else
- return -EINVAL;
+ static_branch_disable(&hugetlb_optimize_vmemmap_key);

return 0;
}
--
2.11.0

2022-05-04 11:24:17

by Mike Kravetz

Subject: Re: [PATCH v9 3/4] mm: hugetlb_vmemmap: use kstrtobool for hugetlb_vmemmap param parsing

On 4/29/22 05:18, Muchun Song wrote:
> Use kstrtobool rather than open coding "on" and "off" parsing in
> mm/hugetlb_vmemmap.c, which is more powerful to handle all kinds
> of parameters like 'Yy1Nn0' or [oO][NnFf] for "on" and "off".
>
> Signed-off-by: Muchun Song <[email protected]>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 6 +++---
> mm/hugetlb_vmemmap.c | 10 +++++-----
> 2 files changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 308da668bbb1..43b8385073ad 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1703,10 +1703,10 @@
> enabled.
> Allows heavy hugetlb users to free up some more
> memory (7 * PAGE_SIZE for each 2MB hugetlb page).
> - Format: { on | off (default) }
> + Format: { [oO][Nn]/Y/y/1 | [oO][Ff]/N/n/0 (default) }
>
> - on: enable the feature
> - off: disable the feature
> + [oO][Nn]/Y/y/1: enable the feature
> + [oO][Ff]/N/n/0: disable the feature

Fancy! :)

>
> Built with CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON=y,
> the default is on.
> diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
> index 6254bb2d4ae5..cc4ec752ec16 100644
> --- a/mm/hugetlb_vmemmap.c
> +++ b/mm/hugetlb_vmemmap.c
> @@ -28,15 +28,15 @@ EXPORT_SYMBOL(hugetlb_optimize_vmemmap_key);
>
> static int __init hugetlb_vmemmap_early_param(char *buf)
> {
> - if (!buf)
> + bool enable;
> +
> + if (kstrtobool(buf, &enable))
> return -EINVAL;
>
> - if (!strcmp(buf, "on"))
> + if (enable)
> static_branch_enable(&hugetlb_optimize_vmemmap_key);
> - else if (!strcmp(buf, "off"))
> - static_branch_disable(&hugetlb_optimize_vmemmap_key);
> else
> - return -EINVAL;
> + static_branch_disable(&hugetlb_optimize_vmemmap_key);
>
> return 0;
> }

Reviewed-by: Mike Kravetz <[email protected]>

--
Mike Kravetz