linux-kernel - Re: [PATCH v2 3/3] arm64: Silence first allocation with CONFIG_ARM64_MODULE

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Date:   Thu, 27 Apr 2017 19:12:19 +0100
From:   Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     linux-arm-kernel@...ts.infradead.org,
        Russell King <linux@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Michal Hocko <mhocko@...e.com>, zijun_hu <zijun_hu@....com>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Chris Wilson <chris@...is-wilson.co.uk>,
        open list <linux-kernel@...r.kernel.org>,
        "open list:MEMORY MANAGEMENT" <linux-mm@...ck.org>,
        angus@...usclark.org
Subject: Re: [PATCH v2 3/3] arm64: Silence first allocation with CONFIG_ARM64_MODULE_PLTS=y



> On 27 Apr 2017, at 19:09, Florian Fainelli <f.fainelli@...il.com> wrote:
> 
>> On 04/27/2017 11:07 AM, Ard Biesheuvel wrote:
>> 
>>> On 27 Apr 2017, at 18:39, Florian Fainelli <f.fainelli@...il.com> wrote:
>>> 
>>> When CONFIG_ARM64_MODULE_PLTS is enabled, the first allocation using the
>>> module space fails, because the module is too big, and then the module
>>> allocation is attempted from vmalloc space. Silence the first allocation
>>> failure in that case by setting __GFP_NOWARN.
>>> 
>>> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
>>> ---
>>> arch/arm64/kernel/module.c | 7 ++++++-
>>> 1 file changed, 6 insertions(+), 1 deletion(-)
>>> 
>>> diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c
>>> index 7f316982ce00..58bd5cfdd544 100644
>>> --- a/arch/arm64/kernel/module.c
>>> +++ b/arch/arm64/kernel/module.c
>>> @@ -32,11 +32,16 @@
>>> 
>>> void *module_alloc(unsigned long size)
>>> {
>>> +    gfp_t gfp_mask = GFP_KERNEL;
>>>   void *p;
>>> 
>>> +#if IS_ENABLED(CONFIG_ARM64_MODULE_PLTS)
>>> +    /* Silence the initial allocation */
>>> +    gfp_mask |= __GFP_NOWARN;
>>> +#endif
>> 
>> Please use IS_ENABLED() instead here
> 
> How do you mean?
> 
> if (IS_ENABLED()) vs. #if IS_ENABLED()?
> 

Apologies, I didn't read carefully.

Use the C if not the preprocessor if

>> 
>>>   p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
>>>               module_alloc_base + MODULES_VSIZE,
>>> -                GFP_KERNEL, PAGE_KERNEL_EXEC, 0,
>>> +                gfp_mask, PAGE_KERNEL_EXEC, 0,
>>>               NUMA_NO_NODE, __builtin_return_address(0));
>>> 
>>>   if (!p && IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) &&
>>> -- 
>>> 2.9.3
>>> 
>> 
>> Other than that, and with Michal's nit addressed:
>> 
>> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
>> 
> 
> 
> -- 
> Florian