Mail Archives: cygwin-developers/1998/04/08/07:59:31
At 09:01 AM 4/8/98 -0400, cgf AT cygnus DOT com wrote:
>>From: ian AT cygnus DOT com (Ian Lance Taylor)
>>Date: 7 Apr 1998 21:03:43 -0700
>>
>>>From: Geoffrey Noer <noer AT cygnus DOT com>
>>>Date: Tue, 7 Apr 1998 18:41:15 -0700 (PDT)
>>
>>>Sergey Okhapkin wrote:
>>>>
>>>> Now I know why _every_ cygwin process have a splitted heap if it allocates
>>>> more than heap_chunk_size bytes of memory (but I will not tell you why this
>>>> happens - think yourself!-) Here is the temporary fix - reserve a large
>>>> amount of memory for heap to avoid fork problem. The fix doesn't affect
>>>> performance.
>>>>
>>>> H:\usr\src\cygnus\cdk\winsup>diff -u shared.cc.orig shared.cc
>>>> --- shared.cc.orig Wed Feb 11 06:15:08 1998
>>>> +++ shared.cc Tue Mar 24 10:44:55 1998
>>>> @@ -96,7 +96,7 @@
>>>>
>>>> reg_session reg;
>>>>
>>>> - heap_chunk_in_mb = reg.get_key ().get_int ("heap_chunk_in_mb", 8);
>>>> + heap_chunk_in_mb = reg.get_key ().get_int ("heap_chunk_in_mb", 128);
>>>> if (heap_chunk_in_mb < 4)
>>>> {
>>>> heap_chunk_in_mb = 4;
>>>
>>>Are there reasons why I shouldn't make this change?
>>
>>On a traditional Unix system, making this change would mean that every
>>process would require 128 MB in the swap file, and your system would
>>rapidly run out of swap space. I don't know how the Windows
>>equivalent of a swap file works, so I don't know whether there would
>>be any equivalent problem.
>
>Since the this just essentially sets aside a contiguous address range I
>could envision an OS which would be intelligent enough to avoid allocating
>swap space until parts of the memory region were committed. I'm having
>a difficult time, however, imagining a *Windows* operating system that
>would be this intelligent.
I believe the NT VMM allows you to do this. But you're right, I'd be
surprised to find out that Win95 can handle this properly. Then again,
I haven't checked it myself yet!:-)
Larry Hall lhall AT rfk DOT com
RFK Partners, Inc. (781) 239-1053
8 Grove Street (781) 239-1655 - FAX
Wellesley, MA 02181 http://www.rfk.com
- Raw text -