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(r_alloc_freeze_level): New variable.

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(r_alloc_freeze, r_alloc_thaw): New functions.
(r_alloc_sbrk): Refuse to move blocs, if frozen.
This commit is contained in:
Karl Heuer 1994-09-20 05:51:50 +00:00
parent b6d6a51cfb
commit 81bd58e880
1 changed files with 30 additions and 2 deletions
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32
src/ralloc.c
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@ -333,6 +333,7 @@ free_bloc (bloc)
/* Interface routines. */
static int use_relocatable_buffers;
static int r_alloc_freeze_level;
/* Obtain SIZE bytes of storage from the free pool, or the system, as
necessary. If relocatable blocs are in use, this means relocating
@ -370,7 +371,7 @@ r_alloc_sbrk (size)
/* Get what we need, plus some extra so we can come here less often. */
SIZE get = size - already_available + extra_bytes;
if (! obtain (get))
if (r_alloc_freeze_level > 0 || ! obtain (get))
return 0;
if (first_bloc)
@ -381,7 +382,8 @@ r_alloc_sbrk (size)
bzero (virtual_break_value, get);
}
/* Can we keep extra_bytes of gap while freeing at least extra_bytes? */
else if (size < 0 && already_available - size > 2 * extra_bytes)
else if (size < 0 && already_available - size > 2 * extra_bytes
&& r_alloc_freeze_level == 0)
{
/* Ok, do so. This is how many to free. */
SIZE give_back = already_available - size - extra_bytes;
@ -481,6 +483,32 @@ r_re_alloc (ptr, size)
return *ptr;
}
/* Disable relocations, after making room for at least SIZE bytes
of non-relocatable heap if possible. The relocatable blocs are
guaranteed to hold still until thawed, even if this means that
malloc must return a null pointer. */
void
r_alloc_freeze (size)
long size;
{
/* If already frozen, we can't make any more room, so don't try. */
if (r_alloc_freeze_level > 0)
size = 0;
/* If we can't get the amount requested, half is better than nothing. */
while (size > 0 && r_alloc_sbrk (size) == 0)
size /= 2;
++r_alloc_freeze_level;
if (size > 0)
r_alloc_sbrk (-size);
}
void
r_alloc_thaw ()
{
if (--r_alloc_freeze_level < 0)
abort ();
}
/* The hook `malloc' uses for the function which gets more space
from the system. */