Re: [dm-devel] [PATCH] Handle error paths.

[Konrad Rzeszutek <konrad virtualiron com>]

On Thu, Jan 08, 2009 at 02:59:45PM -0600, Jonathan Brassow wrote:
> Ummm?

Here is the patch:

https://www.redhat.com/archives/dm-devel/2009-January/msg00058.html

>
>  brassow
>
> On Jan 8, 2009, at 1:25 PM, Konrad Rzeszutek wrote:
>
>>
>> On memory constrained systems, where a large amount of LUNs are
>> assigned (say more enough to make multipath blossom to 70% of available
>> memory space) forking would fail returning -ENOMEM. The kernel has enough
>> free pages for the new process, but when it clones the new child process
>> from the parent process space it accounts the parent process heap space
>> against the child (which counts for more pages than there are free pages).
>>
>> Using vfork passes a flag to clone which will inhibit this calculation
>> and instead check for free pages. The danger in using vfork is that the 
>> child
>> could use the values from the parent, but fortunatly we don't do that and
>> immediately call 'execve' swipping the process space free.
>>
>>
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>
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