diff options
Diffstat (limited to 'malloc/malloc.c')
| -rw-r--r-- | malloc/malloc.c | 197 |
1 files changed, 88 insertions, 109 deletions
diff --git a/malloc/malloc.c b/malloc/malloc.c index 670c9f73f8..51db44f61b 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -1625,8 +1625,10 @@ static INTERNAL_SIZE_T global_max_fast; /* Set value of max_fast. Use impossibly small value if 0. - Precondition: there are no existing fastbin chunks. - Setting the value clears fastchunk bit but preserves noncontiguous bit. + Precondition: there are no existing fastbin chunks in the main arena. + Since do_check_malloc_state () checks this, we call malloc_consolidate () + before changing max_fast. Note other arenas will leak their fast bin + entries if max_fast is reduced. */ #define set_max_fast(s) \ @@ -1790,11 +1792,8 @@ static struct malloc_par mp_ = /* Initialize a malloc_state struct. - This is called only from within malloc_consolidate, which needs - be called in the same contexts anyway. It is never called directly - outside of malloc_consolidate because some optimizing compilers try - to inline it at all call points, which turns out not to be an - optimization at all. (Inlining it in malloc_consolidate is fine though.) + This is called from ptmalloc_init () or from _int_new_arena () + when creating a new arena. */ static void @@ -1972,7 +1971,7 @@ do_check_chunk (mstate av, mchunkptr p) static void do_check_free_chunk (mstate av, mchunkptr p) { - INTERNAL_SIZE_T sz = p->size & ~(PREV_INUSE | NON_MAIN_ARENA); + INTERNAL_SIZE_T sz = chunksize_nomask (p) & ~(PREV_INUSE | NON_MAIN_ARENA); mchunkptr next = chunk_at_offset (p, sz); do_check_chunk (av, p); @@ -1987,7 +1986,7 @@ do_check_free_chunk (mstate av, mchunkptr p) assert ((sz & MALLOC_ALIGN_MASK) == 0); assert (aligned_OK (chunk2mem (p))); /* ... matching footer field */ - assert (prev_size (p) == sz); + assert (prev_size (next_chunk (p)) == sz); /* ... and is fully consolidated */ assert (prev_inuse (p)); assert (next == av->top || inuse (next)); @@ -2047,7 +2046,7 @@ do_check_inuse_chunk (mstate av, mchunkptr p) static void do_check_remalloced_chunk (mstate av, mchunkptr p, INTERNAL_SIZE_T s) { - INTERNAL_SIZE_T sz = p->size & ~(PREV_INUSE | NON_MAIN_ARENA); + INTERNAL_SIZE_T sz = chunksize_nomask (p) & ~(PREV_INUSE | NON_MAIN_ARENA); if (!chunk_is_mmapped (p)) { @@ -2123,8 +2122,11 @@ do_check_malloc_state (mstate av) /* alignment is a power of 2 */ assert ((MALLOC_ALIGNMENT & (MALLOC_ALIGNMENT - 1)) == 0); - /* cannot run remaining checks until fully initialized */ - if (av->top == 0 || av->top == initial_top (av)) + /* Check the arena is initialized. */ + assert (av->top != 0); + + /* No memory has been allocated yet, so doing more tests is not possible. */ + if (av->top == initial_top (av)) return; /* pagesize is a power of 2 */ @@ -3578,21 +3580,16 @@ _int_malloc (mstate av, size_t bytes) if ((victim = last (bin)) != bin) { - if (victim == 0) /* initialization check */ - malloc_consolidate (av); - else - { - bck = victim->bk; - if (__glibc_unlikely (bck->fd != victim)) - malloc_printerr - ("malloc(): smallbin double linked list corrupted"); - set_inuse_bit_at_offset (victim, nb); - bin->bk = bck; - bck->fd = bin; - - if (av != &main_arena) - set_non_main_arena (victim); - check_malloced_chunk (av, victim, nb); + bck = victim->bk; + if (__glibc_unlikely (bck->fd != victim)) + malloc_printerr ("malloc(): smallbin double linked list corrupted"); + set_inuse_bit_at_offset (victim, nb); + bin->bk = bck; + bck->fd = bin; + + if (av != &main_arena) + set_non_main_arena (victim); + check_malloced_chunk (av, victim, nb); #if USE_TCACHE /* While we're here, if we see other chunks of the same size, stash them in the tcache. */ @@ -3619,10 +3616,9 @@ _int_malloc (mstate av, size_t bytes) } } #endif - void *p = chunk2mem (victim); - alloc_perturb (p, bytes); - return p; - } + void *p = chunk2mem (victim); + alloc_perturb (p, bytes); + return p; } } @@ -4320,10 +4316,6 @@ _int_free (mstate av, mchunkptr p, int have_lock) purpose since, among other things, it might place chunks back onto fastbins. So, instead, we need to use a minor variant of the same code. - - Also, because this routine needs to be called the first time through - malloc anyway, it turns out to be the perfect place to trigger - initialization code. */ static void malloc_consolidate(mstate av) @@ -4344,84 +4336,73 @@ static void malloc_consolidate(mstate av) mchunkptr bck; mchunkptr fwd; - /* - If max_fast is 0, we know that av hasn't - yet been initialized, in which case do so below - */ - - if (get_max_fast () != 0) { - atomic_store_relaxed (&av->have_fastchunks, false); - - unsorted_bin = unsorted_chunks(av); + atomic_store_relaxed (&av->have_fastchunks, false); - /* - Remove each chunk from fast bin and consolidate it, placing it - then in unsorted bin. Among other reasons for doing this, - placing in unsorted bin avoids needing to calculate actual bins - until malloc is sure that chunks aren't immediately going to be - reused anyway. - */ + unsorted_bin = unsorted_chunks(av); - maxfb = &fastbin (av, NFASTBINS - 1); - fb = &fastbin (av, 0); - do { - p = atomic_exchange_acq (fb, NULL); - if (p != 0) { - do { - check_inuse_chunk(av, p); - nextp = p->fd; - - /* Slightly streamlined version of consolidation code in free() */ - size = chunksize (p); - nextchunk = chunk_at_offset(p, size); - nextsize = chunksize(nextchunk); - - if (!prev_inuse(p)) { - prevsize = prev_size (p); - size += prevsize; - p = chunk_at_offset(p, -((long) prevsize)); - unlink(av, p, bck, fwd); - } + /* + Remove each chunk from fast bin and consolidate it, placing it + then in unsorted bin. Among other reasons for doing this, + placing in unsorted bin avoids needing to calculate actual bins + until malloc is sure that chunks aren't immediately going to be + reused anyway. + */ - if (nextchunk != av->top) { - nextinuse = inuse_bit_at_offset(nextchunk, nextsize); + maxfb = &fastbin (av, NFASTBINS - 1); + fb = &fastbin (av, 0); + do { + p = atomic_exchange_acq (fb, NULL); + if (p != 0) { + do { + check_inuse_chunk(av, p); + nextp = p->fd; + + /* Slightly streamlined version of consolidation code in free() */ + size = chunksize (p); + nextchunk = chunk_at_offset(p, size); + nextsize = chunksize(nextchunk); + + if (!prev_inuse(p)) { + prevsize = prev_size (p); + size += prevsize; + p = chunk_at_offset(p, -((long) prevsize)); + unlink(av, p, bck, fwd); + } - if (!nextinuse) { - size += nextsize; - unlink(av, nextchunk, bck, fwd); - } else - clear_inuse_bit_at_offset(nextchunk, 0); + if (nextchunk != av->top) { + nextinuse = inuse_bit_at_offset(nextchunk, nextsize); - first_unsorted = unsorted_bin->fd; - unsorted_bin->fd = p; - first_unsorted->bk = p; + if (!nextinuse) { + size += nextsize; + unlink(av, nextchunk, bck, fwd); + } else + clear_inuse_bit_at_offset(nextchunk, 0); - if (!in_smallbin_range (size)) { - p->fd_nextsize = NULL; - p->bk_nextsize = NULL; - } + first_unsorted = unsorted_bin->fd; + unsorted_bin->fd = p; + first_unsorted->bk = p; - set_head(p, size | PREV_INUSE); - p->bk = unsorted_bin; - p->fd = first_unsorted; - set_foot(p, size); + if (!in_smallbin_range (size)) { + p->fd_nextsize = NULL; + p->bk_nextsize = NULL; } - else { - size += nextsize; - set_head(p, size | PREV_INUSE); - av->top = p; - } + set_head(p, size | PREV_INUSE); + p->bk = unsorted_bin; + p->fd = first_unsorted; + set_foot(p, size); + } - } while ( (p = nextp) != 0); + else { + size += nextsize; + set_head(p, size | PREV_INUSE); + av->top = p; + } - } - } while (fb++ != maxfb); - } - else { - malloc_init_state(av); - check_malloc_state(av); - } + } while ( (p = nextp) != 0); + + } + } while (fb++ != maxfb); } /* @@ -4688,7 +4669,7 @@ _int_memalign (mstate av, size_t alignment, size_t bytes) static int mtrim (mstate av, size_t pad) { - /* Ensure initialization/consolidation */ + /* Ensure all blocks are consolidated. */ malloc_consolidate (av); const size_t ps = GLRO (dl_pagesize); @@ -4819,10 +4800,6 @@ int_mallinfo (mstate av, struct mallinfo *m) int nblocks; int nfastblocks; - /* Ensure initialization */ - if (av->top == 0) - malloc_consolidate (av); - check_malloc_state (av); /* Account for top */ @@ -5071,11 +5048,13 @@ __libc_mallopt (int param_number, int value) if (__malloc_initialized < 0) ptmalloc_init (); __libc_lock_lock (av->mutex); - /* Ensure initialization/consolidation */ - malloc_consolidate (av); LIBC_PROBE (memory_mallopt, 2, param_number, value); + /* We must consolidate main arena before changing max_fast + (see definition of set_max_fast). */ + malloc_consolidate (av); + switch (param_number) { case M_MXFAST: |