[PATCH] vmalloc: Removing incorrect logs when vmalloc failed

[PATCH] vmalloc: Removing incorrect logs when vmalloc failed

[Tian Tao]

It is not possible to increase size with vmalloc=<size> in arm64
architecture and it will mislead.however vmalloc return failure
is a rare occurrence in 'many architectures including arm64'.

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
---
 mm/vmalloc.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 89e83d3..c7b5a9a 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1238,8 +1238,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
 	}
 
 	if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit())
-		pr_warn("vmap allocation for size %lu failed: use vmalloc=<size> to increase size\n",
-			size);
+		pr_warn("vmap allocation for size %lu failed\n", size);
 
 	kmem_cache_free(vmap_area_cachep, va);
 	return ERR_PTR(-EBUSY);
-- 
2.7.4

Re: [PATCH] vmalloc: Removing incorrect logs when vmalloc failed

[Anshuman Khandual]

On 07/07/2020 02:43 PM, Tian Tao wrote:
> It is not possible to increase size with vmalloc=<size> in arm64
> architecture and it will mislead.however vmalloc return failure
> is a rare occurrence in 'many architectures including arm64'.

But there is a chance that vmalloc() might work on architectures
that support 'vmalloc=' command line i.e after a change and this
information here might be helpful in those cases.

> 
> Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
> ---
>  mm/vmalloc.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 89e83d3..c7b5a9a 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1238,8 +1238,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
>  	}
>  
>  	if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit())
> -		pr_warn("vmap allocation for size %lu failed: use vmalloc=<size> to increase size\n",
> -			size);
> +		pr_warn("vmap allocation for size %lu failed\n", size);
>  
>  	kmem_cache_free(vmap_area_cachep, va);
>  	return ERR_PTR(-EBUSY);
> 

Re: [PATCH] vmalloc: Removing incorrect logs when vmalloc failed

[Uladzislau Rezki]

On Tue, Jul 07, 2020 at 03:18:54PM +0530, Anshuman Khandual wrote:
> 
> 
> On 07/07/2020 02:43 PM, Tian Tao wrote:
> > It is not possible to increase size with vmalloc=<size> in arm64
> > architecture and it will mislead.however vmalloc return failure
> > is a rare occurrence in 'many architectures including arm64'.
> 
> But there is a chance that vmalloc() might work on architectures
> that support 'vmalloc=' command line i.e after a change and this
> information here might be helpful in those cases.
> 
Agree. At least i see a few users of it:

<snip>
urezki@pc638:~/data/coding/linux-next.git$ grep -rn early_param ./arch/ | grep vmalloc
./arch/arm/mm/mmu.c:1152:early_param("vmalloc", early_vmalloc);
./arch/unicore32/mm/mmu.c:276:early_param("vmalloc", early_vmalloc);
./arch/x86/mm/pgtable_32.c:86:early_param("vmalloc", parse_vmalloc);
urezki@pc638:~/data/coding/linux-next.git$
<snip>

Thanks!

--
Vlad Rezki

Re: [PATCH] vmalloc: Removing incorrect logs when vmalloc failed

[Uladzislau Rezki]

> > > On 07/07/2020 02:43 PM, Tian Tao wrote:
> > > > It is not possible to increase size with vmalloc=<size> in arm64
> > > > architecture and it will mislead.however vmalloc return failure
> > > > is a rare occurrence in 'many architectures including arm64'.
> > > 
> > > But there is a chance that vmalloc() might work on architectures
> > > that support 'vmalloc=' command line i.e after a change and this
> > > information here might be helpful in those cases.
> > > 
> > Agree. At least i see a few users of it:
> > 
> > <snip>
> > urezki@pc638:~/data/coding/linux-next.git$ grep -rn early_param ./arch/ | grep vmalloc
> > ./arch/arm/mm/mmu.c:1152:early_param("vmalloc", early_vmalloc);
> > ./arch/unicore32/mm/mmu.c:276:early_param("vmalloc", early_vmalloc);
> > ./arch/x86/mm/pgtable_32.c:86:early_param("vmalloc", parse_vmalloc);
> > urezki@pc638:~/data/coding/linux-next.git$
> > <snip>
> > 
> I'm actually having this problem with the arm64 architecture at centos 7.6
> and pagesize is 64K.
> I followed the prompts and added vmalloc=<size> to the command to increase
> the size of the vmalloc.and found out it's not worked.
> It took me some time to find out that this doesn't work for the arm64
> architecture, so this log is misleading on arm64.
>
Agree, it can take time to understand some code or logic behind of it.
So in that case having good documentation or comments always help.

> I think it's better not to be prompted than to be prompted incorrectly.
> I'm sure there will be others with similar problems.
> So I'd like to solve this problem this time, Please help me with your
> suggestions.
> If I change the PATCH to the following, will you accept it?
> 
Actually it is not up to me to decide what to take or not. Andrew Morton
is the key person here :) I can just review or make some comments same
as others.

>       if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit())
> +#ifdef CONFIG_ARM64 && CONFIG_XXX
> +        pr_warn("vmap allocation for size %lu failed\n", size);
> +#else
>           pr_warn("vmap allocation for size %lu failed: use vmalloc=<size>
> to increase size\n",
>               size);
> +#endif
>
I do not have a strong opinion here, but counting arches seems odd.
Maybe modify the string with following message:

<snip>
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 1f46c3b86f9f..0aa26bc128d7 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1202,7 +1202,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
        }
 
        if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit())
-               pr_warn("vmap allocation for size %lu failed: use vmalloc=<size> to increase size\n",
+               pr_warn("vmap allocation for size %lu failed: use vmalloc=<size> to increase size, if your ARCH supports it\n",
                        size);
 
        kmem_cache_free(vmap_area_cachep, va);
<snip>

--
Vlad Rezki

Re: [PATCH] vmalloc: Removing incorrect logs when vmalloc failed

[tiantao (H)]

在 2020/7/8 21:48, Uladzislau Rezki 写道:
>>>> On 07/07/2020 02:43 PM, Tian Tao wrote:
>>>>> It is not possible to increase size with vmalloc=<size> in arm64
>>>>> architecture and it will mislead.however vmalloc return failure
>>>>> is a rare occurrence in 'many architectures including arm64'.
>>>>
>>>> But there is a chance that vmalloc() might work on architectures
>>>> that support 'vmalloc=' command line i.e after a change and this
>>>> information here might be helpful in those cases.
>>>>
>>> Agree. At least i see a few users of it:
>>>
>>> <snip>
>>> urezki@pc638:~/data/coding/linux-next.git$ grep -rn early_param ./arch/ | grep vmalloc
>>> ./arch/arm/mm/mmu.c:1152:early_param("vmalloc", early_vmalloc);
>>> ./arch/unicore32/mm/mmu.c:276:early_param("vmalloc", early_vmalloc);
>>> ./arch/x86/mm/pgtable_32.c:86:early_param("vmalloc", parse_vmalloc);
>>> urezki@pc638:~/data/coding/linux-next.git$
>>> <snip>
>>>
>> I'm actually having this problem with the arm64 architecture at centos 7.6
>> and pagesize is 64K.
>> I followed the prompts and added vmalloc=<size> to the command to increase
>> the size of the vmalloc.and found out it's not worked.
>> It took me some time to find out that this doesn't work for the arm64
>> architecture, so this log is misleading on arm64.
>>
> Agree, it can take time to understand some code or logic behind of it.
> So in that case having good documentation or comments always help.
> 
>> I think it's better not to be prompted than to be prompted incorrectly.
>> I'm sure there will be others with similar problems.
>> So I'd like to solve this problem this time, Please help me with your
>> suggestions.
>> If I change the PATCH to the following, will you accept it?
>>
> Actually it is not up to me to decide what to take or not. Andrew Morton
> is the key person here :) I can just review or make some comments same
> as others.
> 
>>        if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit())
>> +#ifdef CONFIG_ARM64 && CONFIG_XXX
>> +        pr_warn("vmap allocation for size %lu failed\n", size);
>> +#else
>>            pr_warn("vmap allocation for size %lu failed: use vmalloc=<size>
>> to increase size\n",
>>                size);
>> +#endif
>>
> I do not have a strong opinion here, but counting arches seems odd.
> Maybe modify the string with following message:
> 
> <snip>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 1f46c3b86f9f..0aa26bc128d7 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1202,7 +1202,7 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
>          }
>   
>          if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit())
> -               pr_warn("vmap allocation for size %lu failed: use vmalloc=<size> to increase size\n",
> +               pr_warn("vmap allocation for size %lu failed: use vmalloc=<size> to increase size, if your ARCH supports it\n",
>                          size);
>   
>          kmem_cache_free(vmap_area_cachep, va);
> <snip>
> 
Thanks, that's a good suggestion, I'll send v2 as you suggested!
> --
> Vlad Rezki
> 
> .
>