Re: recent head having significantly less "avail memory"

From: Guido Falsi via freebsd-current <freebsd-current_at_freebsd.org>
Date: Mon, 13 Sep 2021 18:11:41 UTC
On 13/09/21 19:08, Konstantin Belousov wrote:
> On Mon, Sep 13, 2021 at 02:59:25PM +0200, Guido Falsi via freebsd-current wrote:
>> Hi,
>>
>> I updated head recently and today I noticed a difference which looks wrong.
>>
>> At boodt the new head shows signifcantly less avail memory than before,
>> around 3 GiB less.
>>
>> I moved from commit 71fbc6faed6 [1] where I got:
>>
>> Aug 28 22:03:03 marvin kernel: real memory  = 17179869184 (16384 MB)
>> Aug 28 22:03:03 marvin kernel: avail memory = 16590352384 (15821 MB)
>>
>> to commit 7955efd574b [2] where I get:
>>
>> Sep 13 10:44:40 marvin kernel: real memory  = 17179869184 (16384 MB)
>> Sep 13 10:44:40 marvin kernel: avail memory = 13298876416 (12682 MB)
>>
>> I'm seeing this on multiple machines.
>>
>> Unluckily bisecting and trying an older loader.efi in sseparate tests did
>> not give me any more insight.
>>
>> The recent changes to efi loader, starting with commit 6032b6ba9596 [3] look
>> like a possible trigger to this, but I have been unable to confirm it.
>>
>> Any suggesstions on how to proceed to debug thiss? ANy idea what a fix could
>> be?
> 
> Is this UEFI or bios boot?

Machine is UEFI

> Provide verbose dmesg for old and new boots on the same machine.
> For UEFI boot, show output of 'sysctl machdep.efi_map', again for old
> and new boots.
> 

I'm not sure how to get the verbose data for the old boot, since I've 
been unable to revert the machine to the old state. I'll try anyway though.

Anyway this is happening on tree different machines. I forgot to mention 
they are using a custom kernel. I don't think it makes a difference but 
I'll also test GENERIC, just in case.

-- 
Guido Falsi <mad@madpilot.net>