diff mbox series

[v10,3/4] mm: hugetlb_vmemmap: use kstrtobool for hugetlb_vmemmap param parsing

Message ID 20220509062703.64249-4-songmuchun@bytedance.com (mailing list archive)
State New
Headers show
Series add hugetlb_optimize_vmemmap sysctl | expand

Commit Message

Muchun Song May 9, 2022, 6:27 a.m. UTC
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 <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
---
 Documentation/admin-guide/kernel-parameters.txt |  6 +++---
 mm/hugetlb_vmemmap.c                            | 10 +++++-----
 2 files changed, 8 insertions(+), 8 deletions(-)

Comments

David Hildenbrand May 12, 2022, 7:41 a.m. UTC | #1
On 09.05.22 08:27, 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 <songmuchun@bytedance.com>
> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
> ---
>  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) }

Really? Can we make the syntax even harder to parse for human beings?! :)

Not to mention that it's partially wrong? What about "oFf" ? That would
have to be [oO][Ff][Ff]

Honestly, "on | off" is good enough. That "oN" and friends work is just
a "nice to have" IMHO. No need to over-complicate this description.
>  
> -			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;
>  }


Apart from that

Acked-by: David Hildenbrand <david@redhat.com>
Muchun Song May 12, 2022, 11:23 a.m. UTC | #2
On Thu, May 12, 2022 at 09:41:22AM +0200, David Hildenbrand wrote:
> On 09.05.22 08:27, 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 <songmuchun@bytedance.com>
> > Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
> > ---
> >  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) }
> 
> Really? Can we make the syntax even harder to parse for human beings?! :)
> 
> Not to mention that it's partially wrong? What about "oFf" ? That would
> have to be [oO][Ff][Ff]
> 
> Honestly, "on | off" is good enough. That "oN" and friends work is just
> a "nice to have" IMHO. No need to over-complicate this description.

Got it. How about also telling users "on/1 | off/0"? Because 0 and
1 are also widely used to disable/enable a knob.

> >  
> > -			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;
> >  }
> 
> 
> Apart from that
> 
> Acked-by: David Hildenbrand <david@redhat.com>
>

Thanks.

> -- 
> Thanks,
> 
> David / dhildenb
> 
>
diff mbox series

Patch

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;
 }