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* cygheap.h (struct user_heap_info): Add slop member.

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* heap.cc (heap_init): Add slop factor to heap allocation.  Add
	comment.
	* mmap.cc (MapViewNT): Allocate memory maps top down.
	(fhandler_dev_zero::mmap): Ditto.
	* shared.cc (shared_info::heap_slop_size): New method.
	(shared_info::heap_chunk_size): Don't use debug_printf at early stage.
	* shared_info.h (SHARED_INFO_CB): Accomodate change to shared_info.
	(CURR_SHARED_MAGIC): Ditto.
	(class shared_info): Add heap_slop member.  Declare heap_slop_size.
	* wincap.h: Define heapslop throughout.
	* wincap.cc: Ditto.
This commit is contained in:
Corinna Vinschen
2006-10-31 18:41:16 +00:00
parent 9740f34d11
commit c2b10dc4d8
8 changed files with 91 additions and 10 deletions
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27
winsup/cygwin/heap.cc
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@ -41,21 +41,38 @@ heap_init ()
if (!cygheap->user_heap.base)
{
cygheap->user_heap.chunk = cygwin_shared->heap_chunk_size ();
/* For some obscure reason Vista and 2003 sometimes reserve space after
calls to CreateProcess overlapping the spot where the heap has been
allocated. This apparently spoils fork. The behaviour looks quite
arbitrary. Experiments on Vista show a memory size of 0x37e000 or
0x1fd000 overlapping the usual heap by at most 0x1ed000. So what
we do here is to allocate the heap with an extra slop of (by default)
0x200000 and set the appropriate pointers to the start of the heap
area + slop. A forking child then creates its heap at the new start
address and without the slop factor. Since this is not entirely
foolproof we add a registry setting "heap_slop_in_mb" so the slop
factor can be influenced by the user if the need arises. */
cygheap->user_heap.slop = cygwin_shared->heap_slop_size ();
while (cygheap->user_heap.chunk >= MINHEAP_SIZE)
{
/* Initialize page mask and default heap size. Preallocate a heap
* to assure contiguous memory. */
cygheap->user_heap.ptr = cygheap->user_heap.top =
cygheap->user_heap.base =
VirtualAlloc (NULL, cygheap->user_heap.chunk, alloctype, PAGE_NOACCESS);
VirtualAlloc (NULL, cygheap->user_heap.chunk
+ cygheap->user_heap.slop,
alloctype, PAGE_NOACCESS);
if (cygheap->user_heap.base)
break;
cygheap->user_heap.chunk -= 1 * 1024 * 1024;
}
if (cygheap->user_heap.base == NULL)
api_fatal ("unable to allocate heap, heap_chunk_size %d, %E",
cygheap->user_heap.chunk);
cygheap->user_heap.max = (char *) cygheap->user_heap.base + cygheap->user_heap.chunk;
api_fatal ("unable to allocate heap, heap_chunk_size %p, slop %p, %E",
cygheap->user_heap.chunk, cygheap->user_heap.slop);
cygheap->user_heap.base = (void *) ((char *) cygheap->user_heap.base
+ cygheap->user_heap.slop);
cygheap->user_heap.ptr = cygheap->user_heap.top = cygheap->user_heap.base;
cygheap->user_heap.max = (char *) cygheap->user_heap.base
+ cygheap->user_heap.chunk;
}
else
{