Re: hugetlbfs not working

[Anthony Liguori <anthony@codemonkey.ws>]

Alexander Graf wrote:
> On Mar 27, 2008, at 4:19 PM, Avi Kivity wrote:
>
>   
>> Alexander Graf wrote:
>>     
>>> Hi,
>>>
>>> I'm currently trying to get hugetlbfs working on the current git   
>>> version and am quite puzzled to see it not working. It appears as  
>>> if  the ftruncate call fails:
>>>
>>> open("/dev/hugetlbfs//kvm.vI3G8z", O_RDWR|O_CREAT|O_EXCL, 0600) = 7
>>> unlink("/dev/hugetlbfs//kvm.vI3G8z")    = 0
>>> ftruncate(7, 157286400)                 = -1 EINVAL (Invalid  
>>> argument)
>>> dup(2)                                  = 8
>>> fcntl(8, F_GETFL)                       = 0x8001 (flags O_WRONLY|  
>>> O_LARGEFILE)
>>> close(8)                                = 0
>>> write(2, "ftruncate: Invalid argument\n", 28ftruncate: Invalid  
>>> argument
>>> ) = 28
>>> close(7)                                = 0
>>>
>>> My host kernel is a 2.6.22.
>>>
>>> Is this supposed to work? The first version did not have the  
>>> ftruncate  call, so maybe it doesn't work at all with hugetlbfs?
>>>
>>>       
>> Are you on i386 non-pae?  that has 4MB pages, while you're asking  
>> for for 37.5 4MB pages.
>>
>> Try adding 2MB to the requested memory size.
>>     
>
> I'm on x86_64 and /proc/meminfo tells me:
>
> HugePages_Total:  1435
> HugePages_Free:   1435
> HugePages_Rsvd:      0
> Hugepagesize:     2048 kB
>
> I also reserved all available huge pages:
>
> % cat /proc/sys/vm/nr_hugepages
> 1435
>
> Changing the guest memory size using -m does not help.
>   

If you don't bail when ftruncate fails, does it work as expected for 
you?  Perhaps older versions of hugetlbfs didn't support truncate.

Regards,

Anthony Liguori

> Alex
>
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