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Increase success rate of fallback lmalloc

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* src/alloc.c (lmalloc, lrealloc): Reallocate with (typically)
larger and larger sizes, to increase the probability that
the allocator will return a Lisp-aligned pointer.
This commit is contained in:
Paul Eggert 2016-02-08 20:24:55 -08:00
parent a3bf4a387f
commit b1079c0f86
1 changed files with 18 additions and 4 deletions
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22
src/alloc.c
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@ -1380,7 +1380,12 @@ laligned (void *p, size_t size)
}
/* Like malloc and realloc except that if SIZE is Lisp-aligned, make
sure the result is too. */
sure the result is too, if necessary by reallocating (typically
with larger and larger sizes) until the allocator returns a
Lisp-aligned pointer. Code that needs to allocate C heap memory
for a Lisp object should use one of these functions to obtain a
pointer P; that way, if T is an enum Lisp_Type value and L ==
make_lisp_ptr (P, T), then XPNTR (L) == P and XTYPE (L) == T. */
static void *
lmalloc (size_t size)
@ -1397,6 +1402,9 @@ lmalloc (size_t size)
if (laligned (p, size))
break;
free (p);
size_t bigger;
if (! INT_ADD_WRAPV (size, GCALIGNMENT, &bigger))
size = bigger;
}
eassert ((intptr_t) p % GCALIGNMENT == 0);
@ -1406,9 +1414,15 @@ lmalloc (size_t size)
static void *
lrealloc (void *p, size_t size)
{
do
p = realloc (p, size);
while (! laligned (p, size));
while (true)
{
p = realloc (p, size);
if (laligned (p, size))
break;
size_t bigger;
if (! INT_ADD_WRAPV (size, GCALIGNMENT, &bigger))
size = bigger;
}
eassert ((intptr_t) p % GCALIGNMENT == 0);
return p;