diff options
Diffstat (limited to 'malloc')
| -rw-r--r-- | malloc/malloc.c | 91 |
1 files changed, 19 insertions, 72 deletions
diff --git a/malloc/malloc.c b/malloc/malloc.c index 91728ce..9d646ab 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -2075,12 +2075,13 @@ static void do_check_chunk (mstate av, mchunkptr p) { unsigned long sz = chunksize (p); - /* min and max possible addresses assuming contiguous allocation */ - char *max_address = (char *) (av->top) + chunksize (av->top); - char *min_address = max_address - av->system_mem; if (!chunk_is_mmapped (p)) { + /* min and max possible addresses assuming contiguous allocation */ + char *max_address = (char *) (av->top) + chunksize (av->top); + char *min_address = max_address - av->system_mem; + /* Has legal address ... */ if (p != av->top) { @@ -2100,11 +2101,6 @@ do_check_chunk (mstate av, mchunkptr p) } else { - /* address is outside main heap */ - if (contiguous (av) && av->top != initial_top (av)) - { - assert (((char *) p) < min_address || ((char *) p) >= max_address); - } /* chunk is page-aligned */ assert (((prev_size (p) + sz) & (GLRO (dl_pagesize) - 1)) == 0); /* mem is aligned */ @@ -2404,34 +2400,16 @@ do_check_malloc_state (mstate av) /* ----------- Routines dealing with system allocation -------------- */ -/* - sysmalloc handles malloc cases requiring more memory from the system. - On entry, it is assumed that av->top does not have enough - space to service request for nb bytes, thus requiring that av->top - be extended or replaced. - */ +/* Allocate a mmap chunk - used for large block sizes or as a fallback. + Round up size to nearest page. Add padding if MALLOC_ALIGNMENT is + larger than CHUNK_HDR_SZ. Add SIZE_SZ at the end since there is no + following chunk whose prev_size field could be used. */ static void * -sysmalloc_mmap (INTERNAL_SIZE_T nb, size_t pagesize, int extra_flags, mstate av) +sysmalloc_mmap (INTERNAL_SIZE_T nb, size_t pagesize, int extra_flags) { - long int size; - - /* - Round up size to nearest page. For mmapped chunks, the overhead is one - SIZE_SZ unit larger than for normal chunks, because there is no - following chunk whose prev_size field could be used. - - See the front_misalign handling below, for glibc there is no need for - further alignments unless we have have high alignment. - */ - if (MALLOC_ALIGNMENT == CHUNK_HDR_SZ) - size = ALIGN_UP (nb + SIZE_SZ, pagesize); - else - size = ALIGN_UP (nb + SIZE_SZ + MALLOC_ALIGN_MASK, pagesize); - - /* Don't try if size wraps around 0. */ - if ((unsigned long) (size) <= (unsigned long) (nb)) - return MAP_FAILED; + size_t padding = MALLOC_ALIGNMENT - CHUNK_HDR_SZ; + size_t size = ALIGN_UP (nb + padding + SIZE_SZ, pagesize); char *mm = (char *) MMAP (NULL, size, mtag_mmap_flags | PROT_READ | PROT_WRITE, @@ -2443,41 +2421,10 @@ sysmalloc_mmap (INTERNAL_SIZE_T nb, size_t pagesize, int extra_flags, mstate av) __set_vma_name (mm, size, " glibc: malloc"); - /* - The offset to the start of the mmapped region is stored in the prev_size - field of the chunk. This allows us to adjust returned start address to - meet alignment requirements here and in memalign(), and still be able to - compute proper address argument for later munmap in free() and realloc(). - */ - - INTERNAL_SIZE_T front_misalign; /* unusable bytes at front of new space */ - - if (MALLOC_ALIGNMENT == CHUNK_HDR_SZ) - { - /* For glibc, chunk2mem increases the address by CHUNK_HDR_SZ and - MALLOC_ALIGN_MASK is CHUNK_HDR_SZ-1. Each mmap'ed area is page - aligned and therefore definitely MALLOC_ALIGN_MASK-aligned. */ - assert (((INTERNAL_SIZE_T) chunk2mem (mm) & MALLOC_ALIGN_MASK) == 0); - front_misalign = 0; - } - else - front_misalign = (INTERNAL_SIZE_T) chunk2mem (mm) & MALLOC_ALIGN_MASK; - - mchunkptr p; /* the allocated/returned chunk */ - - if (front_misalign > 0) - { - ptrdiff_t correction = MALLOC_ALIGNMENT - front_misalign; - p = (mchunkptr) (mm + correction); - set_prev_size (p, correction); - set_head (p, (size - correction) | IS_MMAPPED); - } - else - { - p = (mchunkptr) mm; - set_prev_size (p, 0); - set_head (p, size | IS_MMAPPED); - } + /* Store offset to start of mmap in prev_size. */ + mchunkptr p = (mchunkptr) (mm + padding); + set_prev_size (p, padding); + set_head (p, (size - padding) | IS_MMAPPED); /* update statistics */ int new = atomic_fetch_add_relaxed (&mp_.n_mmaps, 1) + 1; @@ -2487,7 +2434,7 @@ sysmalloc_mmap (INTERNAL_SIZE_T nb, size_t pagesize, int extra_flags, mstate av) sum = atomic_fetch_add_relaxed (&mp_.mmapped_mem, size) + size; atomic_max (&mp_.max_mmapped_mem, sum); - check_chunk (av, p); + check_chunk (NULL, p); return chunk2mem (p); } @@ -2579,11 +2526,11 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av) { /* There is no need to issue the THP madvise call if Huge Pages are used directly. */ - mm = sysmalloc_mmap (nb, mp_.hp_pagesize, mp_.hp_flags, av); + mm = sysmalloc_mmap (nb, mp_.hp_pagesize, mp_.hp_flags); if (mm != MAP_FAILED) return mm; } - mm = sysmalloc_mmap (nb, pagesize, 0, av); + mm = sysmalloc_mmap (nb, pagesize, 0); if (mm != MAP_FAILED) return mm; tried_mmap = true; @@ -2667,7 +2614,7 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av) /* We can at least try to use to mmap memory. If new_heap fails it is unlikely that trying to allocate huge pages will succeed. */ - char *mm = sysmalloc_mmap (nb, pagesize, 0, av); + char *mm = sysmalloc_mmap (nb, pagesize, 0); if (mm != MAP_FAILED) return mm; } |