Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
Song Muchun | 496 | 91.85% | 1 | 33.33% |
Donet Tom | 38 | 7.04% | 1 | 33.33% |
Tu Jinjiang | 6 | 1.11% | 1 | 33.33% |
Total | 540 | 3 |
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// SPDX-License-Identifier: GPL-2.0 /* * A test case of using hugepage memory in a user application using the * mmap system call with MAP_HUGETLB flag. Before running this program * make sure the administrator has allocated enough default sized huge * pages to cover the 2 MB allocation. */ #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <sys/mman.h> #include <fcntl.h> #include "vm_util.h" #define PAGE_COMPOUND_HEAD (1UL << 15) #define PAGE_COMPOUND_TAIL (1UL << 16) #define PAGE_HUGE (1UL << 17) #define HEAD_PAGE_FLAGS (PAGE_COMPOUND_HEAD | PAGE_HUGE) #define TAIL_PAGE_FLAGS (PAGE_COMPOUND_TAIL | PAGE_HUGE) #define PM_PFRAME_BITS 55 #define PM_PFRAME_MASK ~((1UL << PM_PFRAME_BITS) - 1) static size_t pagesize; static size_t maplength; static void write_bytes(char *addr, size_t length) { unsigned long i; for (i = 0; i < length; i++) *(addr + i) = (char)i; } static unsigned long virt_to_pfn(void *addr) { int fd; unsigned long pagemap; fd = open("/proc/self/pagemap", O_RDONLY); if (fd < 0) return -1UL; lseek(fd, (unsigned long)addr / pagesize * sizeof(pagemap), SEEK_SET); read(fd, &pagemap, sizeof(pagemap)); close(fd); return pagemap & ~PM_PFRAME_MASK; } static int check_page_flags(unsigned long pfn) { int fd, i; unsigned long pageflags; fd = open("/proc/kpageflags", O_RDONLY); if (fd < 0) return -1; lseek(fd, pfn * sizeof(pageflags), SEEK_SET); read(fd, &pageflags, sizeof(pageflags)); if ((pageflags & HEAD_PAGE_FLAGS) != HEAD_PAGE_FLAGS) { close(fd); printf("Head page flags (%lx) is invalid\n", pageflags); return -1; } /* * pages other than the first page must be tail and shouldn't be head; * this also verifies kernel has correctly set the fake page_head to tail * while hugetlb_free_vmemmap is enabled. */ for (i = 1; i < maplength / pagesize; i++) { read(fd, &pageflags, sizeof(pageflags)); if ((pageflags & TAIL_PAGE_FLAGS) != TAIL_PAGE_FLAGS || (pageflags & HEAD_PAGE_FLAGS) == HEAD_PAGE_FLAGS) { close(fd); printf("Tail page flags (%lx) is invalid\n", pageflags); return -1; } } close(fd); return 0; } int main(int argc, char **argv) { void *addr; unsigned long pfn; pagesize = psize(); maplength = default_huge_page_size(); if (!maplength) { printf("Unable to determine huge page size\n"); exit(1); } addr = mmap(NULL, maplength, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, -1, 0); if (addr == MAP_FAILED) { perror("mmap"); exit(1); } /* Trigger allocation of HugeTLB page. */ write_bytes(addr, maplength); pfn = virt_to_pfn(addr); if (pfn == -1UL) { munmap(addr, maplength); perror("virt_to_pfn"); exit(1); } printf("Returned address is %p whose pfn is %lx\n", addr, pfn); if (check_page_flags(pfn) < 0) { munmap(addr, maplength); perror("check_page_flags"); exit(1); } /* munmap() length of MAP_HUGETLB memory must be hugepage aligned */ if (munmap(addr, maplength)) { perror("munmap"); exit(1); } return 0; }
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