[Bug 20331] New: VirtualAlloc() should allocate addresses low to high

http://bugs.winehq.org/show_bug.cgi?id=20331

Summary: VirtualAlloc() should allocate addresses low to high
           Product: Wine
           Version: 1.1.31
          Platform: PC
               URL: http://rh-software.com/
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: ntdll
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

Currently when VirtualAlloc() is called with a NULL address high addresses are
sometimes returned rather than low addresses.  Looking at
http://msdn.microsoft.com/en-us/library/aa366887(VS.85).aspx you will see there
is the MEM_TOP_DOWN option to specify that high addresses should be used, thus
when this is not specified low addresses should be used.  This is the situation
on Windows NT4 through to Server 2008 R2/Windows 7.

To show this effect download http://rh-software.com/downloads/siv.zip, extract
the files and issue the command:
wine siv -save=[memory]=stdout
which on my system gives:
[memory]  [windows]

Area   Start Address  Limit Address  Size               Size   Proportion  
Elapsed    MB/sec

0      0x02B80000     0x67F80000     0x65400000       1.58GB       54.95%    
0.010
1      0x7F000000     0x7FC00000     0x00C00000      12.00MB        0.41%    
0.005
2      0x7FFF0000     0x81FF0000     0x02000000      32.00MB        1.09%    
0.005
3      0xB75C0000     0xB79C0000     0x00400000       4.00MB        0.14%    
0.005
4      0xB6CA0000     0xB70A0000     0x00400000       4.00MB        0.14%    
0.005
5      0xB6890000     0xB6C90000     0x00400000       4.00MB        0.14%    
0.005
...

I think this may only show the issue for systems with >= 3.5GB of ram.  I am
wondering if it might be related to addresses > 0x80000000 (signed vs. unsigned
tests).  Note that SIV is linked with /largeaddressaware.

[Bug 20331] VirtualAlloc() should allocate addresses low to high

http://bugs.winehq.org/show_bug.cgi?id=20331

Dmitry Timoshkov  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
              Alias|VirtualAlloc                |

[Bug 20331] VirtualAlloc() should allocate addresses low to high

http://bugs.winehq.org/show_bug.cgi?id=20331

--- Comment #1 from Alexandre Julliard   2009-10-12 04:10:55 ---
Low addresses are returned until we run out of low address space. After that we
use the system default policy. If your app really depends on this (why?) you'd
have to tweak the linux kernel policy.

[Bug 20331] VirtualAlloc() should allocate addresses low to high

http://bugs.winehq.org/show_bug.cgi?id=20331

--- Comment #2 from [e-mail]  2009-10-12 05:58:38 ---
Created an attachment (id=24048)
 --> (http://bugs.winehq.org/attachment.cgi?id=24048)
Full save from Wine/Linux

[Bug 20331] VirtualAlloc() should allocate addresses low to high

http://bugs.winehq.org/show_bug.cgi?id=20331

--- Comment #3 from [e-mail]  2009-10-12 05:59:06 ---
Created an attachment (id=24049)
 --> (http://bugs.winehq.org/attachment.cgi?id=24049)
Full save frim Windows XP

[Bug 20331] VirtualAlloc() should allocate addresses low to high

http://bugs.winehq.org/show_bug.cgi?id=20331

--- Comment #4 from [e-mail]  2009-10-12 06:22:30 ---
(In reply to comment #1)
> Low addresses are returned until we run out of low address space. After that we
> use the system default policy. If your app really depends on this (why?) you'd
> have to tweak the linux kernel policy.

What is "low address space" ?  Hi guess is addresses < 0x80000000.

I have attached the full save from Linux and looking at the end you will see:

292    0x68630000     0x68A30000     0x00400000       4.00MB        0.14%    
0.005
293    0x68220000     0x68620000     0x00400000       4.00MB        0.14%    
0.005
294    0xB7FD0000     0xBF7D0000     0x07800000     120.00MB        4.07%    
0.005

Total  0x02B80000     0xBF7D0000     0xB8400000       2.88GB     124.00MB    
1.486

which shows low addresses at the end, but why is entry 295 0xB7FD0000 at the
end ?

If you look at the attached results from a Windows XP system you will see that
the addresses increse all the time.  The panel is working out which parts of
the virtual address space is available.  Because Wine does not operate the same
as Windows my code does not work.  Looking at
http://www.microsoft.com/whdc/system/platform/server/PAE/PAEdrv.mspx I found:
Test using the MEM_TOP_DOWN registry setting
This forces all allocations for memory to be allocated from the top down,
instead of the normal bottom up.
Set HKLM\System\CurrentControlSet\Control\Session Manager\Memory
Management\AllocationPreference REG_DWORD = 0x100000
which confirms that by default low addresses should be allocated before high
addresses.

I could change SIV to try and work-a-round this, but feel this is an incorrrect
solution given the fact that Wine should return low addresses before high
addresses.  I also feel having to change the Linux kernel is inappropiate.  I
feel Wine would tell Linux to allocate low to high.

[Bug 20331] VirtualAlloc() should allocate addresses low to high

http://bugs.winehq.org/show_bug.cgi?id=20331

--- Comment #5 from Alexandre Julliard   2009-10-12 07:11:15 ---
What is considered low addresses depend on the preloader allocations. You can
play with the WINEPRELOADRESERVE variable if you want to change that range.

The rest of the memory is under control of the kernel, that's required for Unix
libraries to be able to allocate memory. I don't quite understand why you have
to depend on the order of allocation to determine the available memory (and of
course that may break on Windows too, cf. the registry key you mentioned).

[Bug 20331] VirtualAlloc() should allocate addresses low to high

http://bugs.winehq.org/show_bug.cgi?id=20331

--- Comment #6 from [e-mail]  2009-10-12 07:46:51 ---
SIV does not work as expected when running under Wine.  This is caused by Wine
not allocating low addresses before high addresses.

There are 2 possible solutions:
1) Wine is fixed to operate the same as Windows
2) I change my code to program round this.

When I initially started using Wine I was led to believe that I should not
"work-a-round" bugs in Wine, I should raise bugs and get Wine fixed, assuming
this is still true I feel that 1) is the sensible resolution. Are you going to
fix Wine ?

[Bug 20331] VirtualAlloc() should allocate addresses low to high

http://bugs.winehq.org/show_bug.cgi?id=20331

--- Comment #7 from [e-mail]  2009-10-12 07:47:09 ---
(In reply to comment #5)
I only discovered AllocationPreference today and am considering what to do
about this.  I have searched the wine source for "AllocationPreference" and not
been able to find it, thus I assume Wine does not implement this.  Would you
like me to add a new Bugzilla entry stating Wine should ?

[Bug 20331] VirtualAlloc() should allocate addresses low to high

http://bugs.winehq.org/show_bug.cgi?id=20331

--- Comment #8 from Alexandre Julliard   2009-10-12 08:19:06 ---
(In reply to comment #6)
> SIV does not work as expected when running under Wine.  This is caused by Wine
> not allocating low addresses before high addresses.
>
> There are 2 possible solutions:
> - Wine is fixed to operate the same as Windows
> - I change my code to program round this.
>
> When I initially started using Wine I was led to believe that I should not
> "work-a-round" bugs in Wine, I should raise bugs and get Wine fixed, assuming
> this is still true I feel that 1) is the sensible resolution. Are you going to
> fix Wine ?

Probably not, because that would break many more important things. So yes, in
general fixing Wine is the answer, but when we get into low-level details there
will necessarily be differences that can't be resolved. So for apps that depend
on that sort of low-level behavior (copy protection is another example), the
only remaining approach is to fix the app, or just accept that it won't work on
Wine.

[Bug 20331] VirtualAlloc() should allocate addresses low to high

http://bugs.winehq.org/show_bug.cgi?id=20331

--- Comment #9 from Alexandre Julliard   2009-10-12 08:21:25 ---
(In reply to comment #7)
> (In reply to comment #5)
> I only discovered AllocationPreference today and am considering what to do
> about this.  I have searched the wine source for "AllocationPreference" and not
> been able to find it, thus I assume Wine does not implement this.  Would you
> like me to add a new Bugzilla entry stating Wine should ?

Only if you can find a real application that breaks because it's not
implemented. That seems pretty unlikely.

[Bug 20331] VirtualAlloc() should allocate addresses low to high

http://bugs.winehq.org/show_bug.cgi?id=20331

--- Comment #10 from [e-mail]  2009-10-12 09:53:06 ---
(In reply to comment #8)
> Probably not

OK, I have done a work-a-round which was actually less work than reporting the
bug in Wine !

SIV 4.02 now typically reports:

Area   Start Address  Limit Address  Size               Size   Proportion

0      0x018D0000     0x67CD0000     0x66400000       1.60GB       54.83%
1      0x682F0000     0x7BEF0000     0x13C00000     316.00MB       10.59%
2      0x7C3F0000     0x7CFF0000     0x00C00000      12.00MB        0.40%
3      0x7F000000     0x7FC00000     0x00C00000      12.00MB        0.40%
4      0x7FFF0000     0x81FF0000     0x02000000      32.00MB        1.07%
5      0x821E0000     0xB79E0000     0x35800000     856.00MB       28.69%
6      0xB7FB0000     0xBF7B0000     0x07800000     120.00MB        4.02%

Total  0x018D0000     0xBF7B0000     0xBA800000       2.91GB      88.00MB

Should you choose to correct Wine one day then you could use
http://rh-software.com/downloads/zip/siv_v4.01.zip to test the fix.

I feel this entry should me marked as confirmed, as from what has been said
this clearly the situation.

What should be done with this Bugzilla entry ?

Is there a list of known differences ?, should this be added ?

[Bug 20331] VirtualAlloc() should allocate addresses low to high

http://bugs.winehq.org/show_bug.cgi?id=20331

Austin English  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |download

[Bug 20331] VirtualAlloc() should allocate addresses low to high

http://bugs.winehq.org/show_bug.cgi?id=20331

Alexandre Julliard  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |WONTFIX

--- Comment #11 from Alexandre Julliard   2009-10-12 10:13:15 ---
Since you have a workaround and there is no other known app where it's a
problem, it's a wontfix for now. It can be reopened if we find another app that
needs it.

[Bug 20331] VirtualAlloc() should allocate addresses low to high

http://bugs.winehq.org/show_bug.cgi?id=20331

Vitaliy Margolen  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |CLOSED

--- Comment #12 from Vitaliy Margolen   2009-10-12 20:29:08 ---
Closing