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malloc: Move MORECORE fallback mmap to sysmalloc_mmap_fallback

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So it can be used on hugepage code as well.

Reviewed-by: DJ Delorie <dj@redhat.com>
This commit is contained in:
Adhemerval Zanella 2021-08-30 10:56:55 -03:00
parent c1beb51d08
commit 0849eed45d
1 changed files with 53 additions and 32 deletions
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73
malloc/malloc.c
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@ -2498,6 +2498,51 @@ sysmalloc_mmap (INTERNAL_SIZE_T nb, size_t pagesize, int extra_flags, mstate av)
return chunk2mem (p); 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 * static void *
sysmalloc (INTERNAL_SIZE_T nb, mstate av) sysmalloc (INTERNAL_SIZE_T nb, mstate av)
{ {
@ -2696,37 +2741,13 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
segregated mmap region. segregated mmap region.
*/ */
/* Cannot merge with old top, so add its size back in */ char *mbrk = sysmalloc_mmap_fallback (&size, nb, old_size, pagesize,
if (contiguous (av)) MMAP_AS_MORECORE_SIZE, 0, 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) if (mbrk != MAP_FAILED)
{ {
madvise_thp (mbrk, size);
/* We do not need, and cannot use, another sbrk call to find end */ /* We do not need, and cannot use, another sbrk call to find end */
brk = mbrk; brk = mbrk;
snd_brk = brk + size; 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);
}
} }
} }