From: WANG Cong <xiyou.wangcong@gmail.com>
To: kexec@lists.infradead.org
Subject: Re: Kexec & Memory Zones question
Date: Thu, 12 May 2011 10:03:03 +0000 (UTC) [thread overview]
Message-ID: <iqgb8m$ruq$1@dough.gmane.org> (raw)
In-Reply-To: 20110511150908.GG31633@redhat.com
On Wed, 11 May 2011 11:09:08 -0400, Vivek Goyal wrote:
> We have discussed this in the past and due to various reasons the max
> amount of RAM you can boot your kernel from seems to be 896MB for x86_64
> and 512MB for 32bit. I shall have to open a previous thread with hpa to
> get exact numbers. So loading kernel even higher is not the solution.
>
On the kexec-tools side, I think the limit is hard-coded,
./include/x86/x86-linux.h:250:#define DEFAULT_INITRD_ADDR_MAX 0x37FFFFFF
but we have,
initrd_addr_max = DEFAULT_INITRD_ADDR_MAX;
if (real_mode->protocol_version >= 0x0203) {
initrd_addr_max = real_mode->initrd_addr_max;
dbgprintf("initrd_addr_max is 0x%lx\n", initrd_addr_max);
}
so, from the code, initrd_addr_max can be provided by the bootloader.
I remember on the kernel side there's also such a limit, but I can't
find where it is. I am wondering what prevents us from increasing this
limit to 4G on i386 and even higher on x86_64.
Thanks.
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next prev parent reply other threads:[~2011-05-12 10:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-04 18:35 Kexec & Memory Zones question Sujit V
2011-05-10 9:42 ` WANG Cong
2011-05-11 15:09 ` Vivek Goyal
2011-05-12 10:03 ` WANG Cong [this message]
2011-05-18 2:05 ` Sujit V
2011-05-18 2:40 ` WANG Cong
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