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-rw-r--r--malloc/malloc.c85
1 files changed, 53 insertions, 32 deletions
diff --git a/malloc/malloc.c b/malloc/malloc.c
index 1698d45..32050be 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -2498,6 +2498,51 @@ sysmalloc_mmap (INTERNAL_SIZE_T nb, size_t pagesize, int extra_flags, mstate av)
return chunk2mem (p);
}
+/*
+ Allocate memory using mmap() based on S and NB requested size, aligning to
+ PAGESIZE if required. The EXTRA_FLAGS is used on mmap() call. If the call
+ succeedes S is updated with the allocated size. This is used as a fallback
+ if MORECORE fails.
+ */
+static void *
+sysmalloc_mmap_fallback (long int *s, INTERNAL_SIZE_T nb,
+ INTERNAL_SIZE_T old_size, size_t minsize,
+ size_t pagesize, int extra_flags, mstate av)
+{
+ long int size = *s;
+
+ /* Cannot merge with old top, so add its size back in */
+ if (contiguous (av))
+ size = ALIGN_UP (size + old_size, pagesize);
+
+ /* If we are relying on mmap as backup, then use larger units */
+ if ((unsigned long) (size) < minsize)
+ size = minsize;
+
+ /* Don't try if size wraps around 0 */
+ if ((unsigned long) (size) <= (unsigned long) (nb))
+ return MORECORE_FAILURE;
+
+ char *mbrk = (char *) (MMAP (0, size,
+ mtag_mmap_flags | PROT_READ | PROT_WRITE,
+ extra_flags));
+ if (mbrk == MAP_FAILED)
+ return MAP_FAILED;
+
+#ifdef MAP_HUGETLB
+ if (!(extra_flags & MAP_HUGETLB))
+ madvise_thp (mbrk, size);
+#endif
+
+ /* Record that we no longer have a contiguous sbrk region. After the first
+ time mmap is used as backup, we do not ever rely on contiguous space
+ since this could incorrectly bridge regions. */
+ set_noncontiguous (av);
+
+ *s = size;
+ return mbrk;
+}
+
static void *
sysmalloc (INTERNAL_SIZE_T nb, mstate av)
{
@@ -2696,38 +2741,14 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
segregated mmap region.
*/
- /* Cannot merge with old top, so add its size back in */
- if (contiguous (av))
- size = ALIGN_UP (size + old_size, pagesize);
-
- /* If we are relying on mmap as backup, then use larger units */
- if ((unsigned long) (size) < (unsigned long) (MMAP_AS_MORECORE_SIZE))
- size = MMAP_AS_MORECORE_SIZE;
-
- /* Don't try if size wraps around 0 */
- if ((unsigned long) (size) > (unsigned long) (nb))
- {
- char *mbrk = (char *) (MMAP (0, size,
- mtag_mmap_flags | PROT_READ | PROT_WRITE,
- 0));
-
- if (mbrk != MAP_FAILED)
- {
- madvise_thp (mbrk, size);
-
- /* We do not need, and cannot use, another sbrk call to find end */
- brk = mbrk;
- snd_brk = brk + size;
-
- /*
- Record that we no longer have a contiguous sbrk region.
- After the first time mmap is used as backup, we do not
- ever rely on contiguous space since this could incorrectly
- bridge regions.
- */
- set_noncontiguous (av);
- }
- }
+ char *mbrk = sysmalloc_mmap_fallback (&size, nb, old_size, pagesize,
+ MMAP_AS_MORECORE_SIZE, 0, av);
+ if (mbrk != MAP_FAILED)
+ {
+ /* We do not need, and cannot use, another sbrk call to find end */
+ brk = mbrk;
+ snd_brk = brk + size;
+ }
}
if (brk != (char *) (MORECORE_FAILURE))