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author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2023-11-23 14:29:15 -0300 |
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committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2023-11-29 09:30:04 -0300 |
commit | bc6d79f4ae99206e7ec7d6a8c5abf26cdefc8bff (patch) | |
tree | a906df3c4053624060dc0d61063f1a658eceead1 /malloc | |
parent | a4c3f5f46e850c977cda81c251036475aab8313c (diff) | |
download | glibc-bc6d79f4ae99206e7ec7d6a8c5abf26cdefc8bff.zip glibc-bc6d79f4ae99206e7ec7d6a8c5abf26cdefc8bff.tar.gz glibc-bc6d79f4ae99206e7ec7d6a8c5abf26cdefc8bff.tar.bz2 |
malloc: Improve MAP_HUGETLB with glibc.malloc.hugetlb=2
Even for explicit large page support, allocation might use mmap without
the hugepage bit set if the requested size is smaller than
mmap_threshold. For this case where mmap is issued, MAP_HUGETLB is set
iff the allocation size is larger than the used large page.
To force such allocations to use large pages, also tune the mmap_threhold
(if it is not explicit set by a tunable). This forces allocation to
follow the sbrk path, which will fall back to mmap (which will try large
pages before galling back to default mmap).
Checked on x86_64-linux-gnu.
Reviewed-by: DJ Delorie <dj@redhat.com>
Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Diffstat (limited to 'malloc')
-rw-r--r-- | malloc/arena.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/malloc/arena.c b/malloc/arena.c index a1a75e5..c73f688 100644 --- a/malloc/arena.c +++ b/malloc/arena.c @@ -312,10 +312,17 @@ 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; + { + /* Force mmap for main arena instead of sbrk, so MAP_HUGETLB is always + tried. Also tune the mmap threshold, so allocation smaller than the + large page will also try to use large pages by falling back + to sysmalloc_mmap_fallback on sysmalloc. */ + if (!TUNABLE_IS_INITIALIZED (mmap_threshold)) + do_set_mmap_threshold (mp_.hp_pagesize); + __always_fail_morecore = true; + } } /* Managing heaps and arenas (for concurrent threads) */ |