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

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Date:   Wed, 19 May 2021 13:32:23 +0800
From:   "Xu, Yanfei" <yanfei.xu@...driver.com>
To:     "Russell King (Oracle)" <linux@...linux.org.uk>
Cc:     rppt@...nel.org, ardb@...nel.org, linus.walleij@...aro.org,
        akpm@...ux-foundation.org, carver4lio@....com,
        tiantao6@...ilicon.com, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] arm: make the size of vmalloc in cmdline and meminfo
 uniform



On 5/19/21 12:39 PM, Xu, Yanfei wrote:
> 
> 
> 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!
> 
Hi Russell,

I am not much familar with community contribution. In this case, what
kind of tags should I reply? signed-off-by? Reviewed-by? or any other
tags?

Regards,
Yanfei

> Regards,
> Yanfei
>> -- 
>> RMK's Patch system: 
>> https://urldefense.com/v3/__https://www.armlinux.org.uk/developer/patches/__;!!AjveYdw8EvQ!Mz6E44Glfsb6CPijsZ50Ofca9g8UAgL2MRQpaxa18ZTAIrVQpH0IcyqGDwHSWphEoo8$ 
>> FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
>>