From 98d5fcb8d099a1a868e032c89891c395a2f365c5 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Mon, 16 Aug 2021 15:08:27 -0300 Subject: malloc: Add Huge Page support for mmap With the morecore hook removed, there is not easy way to provide huge pages support on with glibc allocator without resorting to transparent huge pages. And some users and programs do prefer to use the huge pages directly instead of THP for multiple reasons: no splitting, re-merging by the VM, no TLB shootdowns for running processes, fast allocation from the reserve pool, no competition with the rest of the processes unlike THP, no swapping all, etc. This patch extends the 'glibc.malloc.hugetlb' tunable: the value '2' means to use huge pages directly with the system default size, while a positive value means and specific page size that is matched against the supported ones by the system. Currently only memory allocated on sysmalloc() is handled, the arenas still uses the default system page size. To test is a new rule is added tests-malloc-hugetlb2, which run the addes tests with the required GLIBC_TUNABLE setting. On systems without a reserved huge pages pool, is just stress the mmap(MAP_HUGETLB) allocation failure. To improve test coverage it is required to create a pool with some allocated pages. Checked on x86_64-linux-gnu. Reviewed-by: DJ Delorie --- sysdeps/generic/malloc-hugepages.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'sysdeps/generic/malloc-hugepages.c') diff --git a/sysdeps/generic/malloc-hugepages.c b/sysdeps/generic/malloc-hugepages.c index 8fb459a263..946284a33c 100644 --- a/sysdeps/generic/malloc-hugepages.c +++ b/sysdeps/generic/malloc-hugepages.c @@ -29,3 +29,11 @@ __malloc_thp_mode (void) { return malloc_thp_mode_not_supported; } + +/* Return the default transparent huge page size. */ +void +__malloc_hugepage_config (size_t requested, size_t *pagesize, int *flags) +{ + *pagesize = 0; + *flags = 0; +} -- cgit v1.2.3