Re: [PATCH] arm: make the size of vmalloc in cmdline and meminfo uniform

Xu, Yanfei
2021-05-19T05:03:33Z

On 5/18/21 8:06 PM, Russell King (Oracle) wrote:
> [Please note: This e-mail is from an EXTERNAL e-mail address]
>
> On Tue, May 18, 2021 at 12:29:32PM +0100, Russell King (Oracle) wrote:
>> On Tue, May 18, 2021 at 07:12:54PM +0800, Yanfei Xu wrote:
>>> The value of "vmalloc=" set in cmdline is always 8M more than the value
>>> of "VmallocTotal" in meminfo. When use the "vmalloc=" parameter, user
>>> expect to get the size what they input, and no need to consider the 8M
>>> "hole" hided in codes. This commit make real vmalloc size equal to value
>>> of "vmalloc=" in cmdline.
>>>
>>> Also, the commit will reduce the size of vmalloc printed in boot message
>>> by 8M when the size set in cmdline is irrational.
>>
>> Hi,
>>
>> I think I'd like to do several cleanups with this:
>>
>> 1. change vmalloc_min to be an unsigned long.
>> 2. exclude VMALLOC_OFFSET from vmalloc_min, moving it into
>> adjust_lowmem_bounds where vmalloc_min is used.
>> 3. rename vmalloc_min to be vmalloc_start
>> 4. enforce vmalloc_start to be a multiple of 2MiB
>> 5. in early_vmalloc(), calculate vmalloc_max as:
>> VMALLOC_END - (PAGE_OFFSET + SZ_32M + VMALLOC_OFFSET)
>> and use that to set the upper bound of vmalloc_reserve (which is
>> something your patch doesn't do, which I think is a bug.
>>
>> Thoughts?
>
> I've slightly modified the above idea, and will shortly follow up with
> some patches to show the idea a bit better...
>

Thanks for making it better!

Regards,
Yanfei
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