Re: [Xen-devel] [PATCH 1/2] xen{trace/analyze}: don't use 64bit versions of libc functions

[Roger Pau Monnà <roger.pau@xxxxxxxxxx>]

El 22/06/15 a les 16.48, Roger Pau Monnà ha escrit:
> El 22/06/15 a les 12.09, George Dunlap ha escrit:
>> On 06/22/2015 10:59 AM, Roger Pau Monnà wrote:
>>> El 22/06/15 a les 11.08, George Dunlap ha escrit:
>>>> On 06/19/2015 09:58 AM, Roger Pau Monne wrote:
>>>>> This is not needed, neither encouraged. Configure already checks
>>>>> _FILE_OFFSET_BITS and appends it when needed, so that the right functions
>>>>> are used. Also remove the usage of loff_t and O_LARGEFILE for the same
>>>>> reason.
>>>>
>>>> Just so I understand -- are you saying that configure at the tools
>>>> directory level will notice that Linux can handle 64-bit file operations
>>>> and use them automatically?
>>>
>>> Yes, according to the man page [1]:
>>>
>>> "Over time, increases in the size of the stat structure have led to
>>> three successive versions of stat(): sys_stat() (slot __NR_oldstat),
>>> sys_newstat() (slot __NR_stat), and sys_stat64() (new in kernel 2.4;
>>> slot __NR_stat64). The glibc stat() wrapper function hides these details
>>> from applications, invoking the most recent version of the system call
>>> provided by the kernel, and repacking the returned information if
>>> required for old binaries. Similar remarks apply for fstat() and lstat()."
>>
>> OK, if you can confirm that you've actually tested this on a file larger
>> than 4GiB, then:
> 
> No, I have only build tested it since I was trying to unbreak the build.
> I don't think I will have time to test this until tomorrow, sorry for
> the delay.

I've now tested this with a ~5GB file and it seems to work fine, I
haven't seen any error and the output looks reasonable. This was on a
64bit Dom0, if someone has a 32bit Dom0 it would be good to test it
there also.

Roger.


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