malloc: Add THP/madvise support for sbrk

To increase effectiveness with Transparent Huge Page with madvise, the
large page size is use instead page size for sbrk increment for the
main arena.

Checked on x86_64-linux-gnu.

Reviewed-by: DJ Delorie <dj@redhat.com>
This commit is contained in:
Adhemerval Zanella 2021-08-13 10:06:04 -03:00
parent 5f6d8d97c6
commit 7478c9959a
2 changed files with 37 additions and 5 deletions

View File

@ -60,4 +60,12 @@
#define PTR_ALIGN_UP(base, size) \
((__typeof__ (base)) ALIGN_UP ((uintptr_t) (base), (size)))
/* Check if BASE is aligned on SIZE */
#define PTR_IS_ALIGNED(base, size) \
((((uintptr_t) (base)) & (size - 1)) == 0)
/* Returns the ptrdiff_t diference between P1 and P2. */
#define PTR_DIFF(p1, p2) \
((ptrdiff_t)((uintptr_t)(p1) - (uintptr_t)(p2)))
#endif

View File

@ -2023,6 +2023,16 @@ madvise_thp (void *p, INTERNAL_SIZE_T size)
not active. */
if (mp_.thp_pagesize == 0 || size < mp_.thp_pagesize)
return;
/* Linux requires the input address to be page-aligned, and unaligned
inputs happens only for initial data segment. */
if (__glibc_unlikely (!PTR_IS_ALIGNED (p, GLRO (dl_pagesize))))
{
void *q = PTR_ALIGN_DOWN (p, GLRO (dl_pagesize));
size += PTR_DIFF (p, q);
p = q;
}
__madvise (p, size, MADV_HUGEPAGE);
#endif
}
@ -2609,14 +2619,25 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
size -= old_size;
/*
Round to a multiple of page size.
Round to a multiple of page size or huge page size.
If MORECORE is not contiguous, this ensures that we only call it
with whole-page arguments. And if MORECORE is contiguous and
this is not first time through, this preserves page-alignment of
previous calls. Otherwise, we correct to page-align below.
*/
size = ALIGN_UP (size, pagesize);
#if HAVE_TUNABLES && defined (MADV_HUGEPAGE)
/* Defined in brk.c. */
extern void *__curbrk;
if (__glibc_unlikely (mp_.thp_pagesize != 0))
{
uintptr_t top = ALIGN_UP ((uintptr_t) __curbrk + size,
mp_.thp_pagesize);
size = top - (uintptr_t) __curbrk;
}
else
#endif
size = ALIGN_UP (size, GLRO(dl_pagesize));
/*
Don't try to call MORECORE if argument is so big as to appear
@ -2899,10 +2920,8 @@ systrim (size_t pad, mstate av)
long released; /* Amount actually released */
char *current_brk; /* address returned by pre-check sbrk call */
char *new_brk; /* address returned by post-check sbrk call */
size_t pagesize;
long top_area;
pagesize = GLRO (dl_pagesize);
top_size = chunksize (av->top);
top_area = top_size - MINSIZE - 1;
@ -2910,7 +2929,12 @@ systrim (size_t pad, mstate av)
return 0;
/* Release in pagesize units and round down to the nearest page. */
extra = ALIGN_DOWN(top_area - pad, pagesize);
#if HAVE_TUNABLES && defined (MADV_HUGEPAGE)
if (__glibc_unlikely (mp_.thp_pagesize != 0))
extra = ALIGN_DOWN (top_area - pad, mp_.thp_pagesize);
else
#endif
extra = ALIGN_DOWN (top_area - pad, GLRO(dl_pagesize));
if (extra == 0)
return 0;