diff options
| -rw-r--r-- | malloc/malloc.c | 85 |
1 files changed, 53 insertions, 32 deletions
diff --git a/malloc/malloc.c b/malloc/malloc.c index 1698d45d1e..32050be4cc 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)) |