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Date:   Wed, 7 Apr 2021 16:23:35 +0200
From:   Corentin Labbe <clabbe.montjoie@gmail.com>
To:     Bruce Mitchell <bruce.mitchell@linux.vnet.ibm.com>
Cc:     ebiederm@xmission.com, kexec@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: Re: crashkernel reservation failed - No suitable area found on a
 cortina/gemini SoC
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 <34ff1fcc-e9ee-02c2-b2a8-d98a24ce94c3@linux.vnet.ibm.com>
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Le Wed, Apr 07, 2021 at 07:13:04AM -0700, Bruce Mitchell a ?crit :
> On 4/7/2021 05:54, Corentin Labbe wrote:
> > Hello
> > 
> > I try to do kexec on a cortina/gemini SoC.
> > On a "normal" boot, kexec fail to find memory so I added crashkernel=8M to cmdline. (kernel size is ~6M).
> > But now, kernel fail to reserve memory:
> > Load Kern image from 0x30020000 to 0x800000 size 7340032
> > Booting Linux on physical CPU 0x0
> > Linux version 5.12.0-rc5-next-20210401+ (compile@Red) (armv7a-unknown-linux-gnueabihf-gcc (Gentoo 9.3.0-r2 p4) 9.3.0, GNU ld (Gentoo 2.34 p6) 2.34.0) #98 PREEMPT Wed Apr 7 14:14:08 CEST 2021
> > CPU: FA526 [66015261] revision 1 (ARMv4), cr=0000397f
> > CPU: VIVT data cache, VIVT instruction cache
> > OF: fdt: Machine model: Edimax NS-2502
> > Memory policy: Data cache writeback
> > Zone ranges:
> >    Normal   [mem 0x0000000000000000-0x0000000007ffffff]
> >    HighMem  empty
> > Movable zone start for each node
> > Early memory node ranges
> >    node   0: [mem 0x0000000000000000-0x0000000007ffffff]
> > Initmem setup node 0 [mem 0x0000000000000000-0x0000000007ffffff]
> > crashkernel reservation failed - No suitable area found.
> > Built 1 zonelists, mobility grouping on.  Total pages: 32512
> > Kernel command line: console=ttyS0,19200n8 ip=dhcp crashkernel=8M
> > Dentry cache hash table entries: 16384 (order: 4, 65536 bytes, linear)
> > Inode-cache hash table entries: 8192 (order: 3, 32768 bytes, linear)
> > mem auto-init: stack:off, heap alloc:off, heap free:off
> > Memory: 119476K/131072K available (5034K kernel code, 579K rwdata, 1372K rodata, 3020K init, 210K bss, 11596K reserved, 0K cma-reserved, 0K highmem)
> > SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
> > 
> > What can I do ?
> > 
> > Thanks
> > Regards
> > 
> > _______________________________________________
> > kexec mailing list
> > kexec@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/kexec
> > 
> 
> Hello Corentin,
> 
> I see much larger crashkernel=xxM being shown here
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/admin-guide/kdump/kdump.rst
> and from many of my other searches.
> 
> Here is an interesting article on kdump for ARM-32
> https://kaiwantech.wordpress.com/2017/07/13/setting-up-kdump-and-crash-for-arm-32-an-ongoing-saga/
> 
> 
> Here is the kernel command line reference
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/admin-guide/kernel-parameters.txt?h=v5.11#n732
> 
> I feel your frustrations too.

Hello

Thanks but I have already read those documentation.
I search to know why the kernel cannot find 8M of memory ouf of 128.

Regards