From 0f982c182760bd7689769ee7590df592d0a132c0 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Mon, 30 Aug 2021 14:01:00 -0300 Subject: [PATCH] malloc: Enable huge page support on main arena This patch adds support huge page support on main arena allocation, enable with tunable glibc.malloc.hugetlb=2. The patch essentially disable the __glibc_morecore() sbrk() call (similar when memory tag does when sbrk() call does not support it) and fallback to default page size if the memory allocation fails. Checked on x86_64-linux-gnu. Reviewed-by: DJ Delorie --- malloc/arena.c | 4 ++++ malloc/malloc.c | 12 ++++++++++-- malloc/morecore.c | 4 ---- 3 files changed, 14 insertions(+), 6 deletions(-) diff --git a/malloc/arena.c b/malloc/arena.c index e1852f8..3ed4ef3 100644 --- a/malloc/arena.c +++ b/malloc/arena.c @@ -364,6 +364,10 @@ ptmalloc_init (void) # endif TUNABLE_GET (mxfast, size_t, TUNABLE_CALLBACK (set_mxfast)); TUNABLE_GET (hugetlb, size_t, TUNABLE_CALLBACK (set_hugetlb)); + if (mp_.hp_pagesize > 0) + /* Force mmap for main arena instead of sbrk, so hugepages are explicitly + used. */ + __always_fail_morecore = true; #else if (__glibc_likely (_environ != NULL)) { diff --git a/malloc/malloc.c b/malloc/malloc.c index 32050be..b67f2c8 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -2741,8 +2741,16 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av) segregated mmap region. */ - char *mbrk = sysmalloc_mmap_fallback (&size, nb, old_size, pagesize, - MMAP_AS_MORECORE_SIZE, 0, av); + char *mbrk = MAP_FAILED; +#if HAVE_TUNABLES + if (mp_.hp_pagesize > 0) + mbrk = sysmalloc_mmap_fallback (&size, nb, old_size, + mp_.hp_pagesize, mp_.hp_pagesize, + mp_.hp_flags, av); +#endif + if (mbrk == MAP_FAILED) + 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 */ diff --git a/malloc/morecore.c b/malloc/morecore.c index 8168ef1..004cd3e 100644 --- a/malloc/morecore.c +++ b/malloc/morecore.c @@ -15,9 +15,7 @@ License along with the GNU C Library; if not, see . */ -#if defined(SHARED) || defined(USE_MTAG) static bool __always_fail_morecore = false; -#endif /* Allocate INCREMENT more bytes of data space, and return the start of data space, or NULL on errors. @@ -25,10 +23,8 @@ static bool __always_fail_morecore = false; void * __glibc_morecore (ptrdiff_t increment) { -#if defined(SHARED) || defined(USE_MTAG) if (__always_fail_morecore) return NULL; -#endif void *result = (void *) __sbrk (increment); if (result == (void *) -1) -- 2.7.4