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#1 2012-01-27 14:34:30
- gregor
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- From: /planet/tmpfs
- Registered: 2011-06-20
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Can I load updated kernel without reboot.....
can i after an update just reboot my fresh installed kernel instead of rebooting the whole system.... is this possible ?
Last edited by gregor (2012-01-27 14:48:09)
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#2 2012-01-27 14:45:45
- alphaniner
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Re: Can I load updated kernel without reboot.....
'Reboot the kernel' doesn't really make sense. You should change the title to 'Can I load updated kernel without reboot?' to increase your chances of getting a (useful) response.
That said, I saw a thread about this a while back but don't remember the conclusion.
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#3 2012-01-27 14:51:12
- laloch
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- Registered: 2010-02-04
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Re: Can I load updated kernel without reboot.....
No, you can't. If Linux were a microkernel, it would be possible to replace it on-the-fly to some extent.
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#4 2012-01-27 15:16:15
- .:B:.
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Re: Can I load updated kernel without reboot.....
You can, with kexec.
Not guaranteeing you it will work 100% though, but that's for example how the atv-bootloader works for the 1st generation AppleTV. There's ksplice as well, but I don't know if it's free (as in beer) or not.
Last edited by .:B:. (2012-01-27 15:20:30)
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#5 2012-01-27 15:38:44
- laloch
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Re: Can I load updated kernel without reboot.....
kexec is not intented to replace a kernel image under the running workstation. With kexec you still need to kill user processes, then reload the kernel and then go through normal system init.
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#6 2012-01-27 15:42:42
- hadrons123
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- From: chennai
- Registered: 2011-10-07
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Re: Can I load updated kernel without reboot.....
technically kexec doesn't really offload the old kernel.Becoz old kernel is still executing in memory too....
Last edited by hadrons123 (2012-01-27 15:46:21)
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#7 2012-01-27 15:54:03
- laloch
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- Registered: 2010-02-04
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Re: Can I load updated kernel without reboot.....
technically kexec doesn't really offload the old kernel.Becoz old kernel is still executing in memory too....
But it does overwrite the current kernel.
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#8 2012-01-27 21:32:34
- ratcheer
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- Registered: 2011-10-09
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Re: Can I load updated kernel without reboot.....
But it does overwrite the current kernel.
No. No, it doesn't.
Tim
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#9 2012-01-27 21:50:15
- laloch
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Re: Can I load updated kernel without reboot.....
laloch wrote:But it does overwrite the current kernel.
No. No, it doesn't.
See here: http://www.ibm.com/developerworks/linux … tml#N100CF
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#10 2012-01-27 22:40:49
- Leonid.I
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- From: Aethyr
- Registered: 2009-03-22
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Re: Can I load updated kernel without reboot.....
can i after an update just reboot my fresh installed kernel instead of rebooting the whole system.... is this possible ?
You see, the kernel isn't the problem, udev is. Particularly, after updating the kernel you'd like to know if all your devices are correctly recognized and initialized. That's why you need a reboot. Kexec is more an emergency measure than a reboot-replacement.
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#11 2012-01-27 23:46:07
- headkase
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- Registered: 2011-12-06
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Re: Can I load updated kernel without reboot.....
You see, the kernel isn't the problem, udev is. Particularly, after updating the kernel you'd like to know if all your devices are correctly recognized and initialized. That's why you need a reboot. Kexec is more an emergency measure than a reboot-replacement.
Debian, well: at least Squeeze, has kexec installed by default. However you must still "reboot" except you end up skipping the Power On Self Test, and also the GRUB kernel selection, then everything re-initializes and reboots as normal.
Edit
And since kexec is installed by default: every "reboot" is a "kexec reboot." Only power-off then power-on will show you a POST. When I was using Debian kexec was the first package I removed. I like to see a POST. 
Last edited by headkase (2012-01-27 23:53:14)
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#12 2012-01-28 09:56:19
- gregor
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- Posts: 175
Re: Can I load updated kernel without reboot.....
thnx all
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