From: Konstantin Khlebnikov <koct9i@xxxxxxxxx>
This tool induces memory fragmentation via sequential allocation of transparent
huge pages and splitting off everything except their last sub-pages.
Signed-off-by: Konstantin Khlebnikov <koct9i@xxxxxxxxx>
---
tools/testing/selftests/vm/Makefile | 1
tools/testing/selftests/vm/transhuge-stress.c | 144 +++++++++++++++++++++++++
2 files changed, 145 insertions(+)
create mode 100644 tools/testing/selftests/vm/transhuge-stress.c
diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile
index 3f94e1a..4c4b1f6 100644
--- a/tools/testing/selftests/vm/Makefile
+++ b/tools/testing/selftests/vm/Makefile
@@ -3,6 +3,7 @@
CC = $(CROSS_COMPILE)gcc
CFLAGS = -Wall
BINARIES = hugepage-mmap hugepage-shm map_hugetlb thuge-gen hugetlbfstest
+BINARIES += transhuge-stress
all: $(BINARIES)
%: %.c
diff --git a/tools/testing/selftests/vm/transhuge-stress.c b/tools/testing/selftests/vm/transhuge-stress.c
new file mode 100644
index 0000000..fd7f1b4
--- /dev/null
+++ b/tools/testing/selftests/vm/transhuge-stress.c
@@ -0,0 +1,144 @@
+/*
+ * Stress test for transparent huge pages, memory compaction and migration.
+ *
+ * Authors: Konstantin Khlebnikov <koct9i@xxxxxxxxx>
+ *
+ * This is free and unencumbered software released into the public domain.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <err.h>
+#include <time.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/mman.h>
+
+#define PAGE_SHIFT 12
+#define HPAGE_SHIFT 21
+
+#define PAGE_SIZE (1 << PAGE_SHIFT)
+#define HPAGE_SIZE (1 << HPAGE_SHIFT)
+
+#define PAGEMAP_PRESENT(ent) (((ent) & (1ull << 63)) != 0)
+#define PAGEMAP_PFN(ent) ((ent) & ((1ull << 55) - 1))
+
+int pagemap_fd;
+
+int64_t allocate_transhuge(void *ptr)
+{
+ uint64_t ent[2];
+
+ /* drop pmd */
+ if (mmap(ptr, HPAGE_SIZE, PROT_READ | PROT_WRITE,
+ MAP_FIXED | MAP_ANONYMOUS |
+ MAP_NORESERVE | MAP_PRIVATE, -1, 0) != ptr)
+ errx(2, "mmap transhuge");
+
+ if (madvise(ptr, HPAGE_SIZE, MADV_HUGEPAGE))
+ err(2, "MADV_HUGEPAGE");
+
+ /* allocate transparent huge page */
+ *(volatile void **)ptr = ptr;
+
+ if (pread(pagemap_fd, ent, sizeof(ent),
+ (uintptr_t)ptr >> (PAGE_SHIFT - 3)) != sizeof(ent))
+ err(2, "read pagemap");
+
+ if (PAGEMAP_PRESENT(ent[0]) && PAGEMAP_PRESENT(ent[1]) &&
+ PAGEMAP_PFN(ent[0]) + 1 == PAGEMAP_PFN(ent[1]) &&
+ !(PAGEMAP_PFN(ent[0]) & ((1 << (HPAGE_SHIFT - PAGE_SHIFT)) - 1)))
+ return PAGEMAP_PFN(ent[0]);
+
+ return -1;
+}
+
+int main(int argc, char **argv)
+{
+ size_t ram, len;
+ void *ptr, *p;
+ struct timespec a, b;
+ double s;
+ uint8_t *map;
+ size_t map_len;
+
+ ram = sysconf(_SC_PHYS_PAGES);
+ if (ram > SIZE_MAX / sysconf(_SC_PAGESIZE) / 4)
+ ram = SIZE_MAX / 4;
+ else
+ ram *= sysconf(_SC_PAGESIZE);
+
+ if (argc == 1)
+ len = ram;
+ else if (!strcmp(argv[1], "-h"))
+ errx(1, "usage: %s [size in MiB]", argv[0]);
+ else
+ len = atoll(argv[1]) << 20;
+
+ warnx("allocate %zd transhuge pages, using %zd MiB virtual memory"
+ " and %zd MiB of ram", len >> HPAGE_SHIFT, len >> 20,
+ len >> (20 + HPAGE_SHIFT - PAGE_SHIFT - 1));
+
+ pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
+ if (pagemap_fd < 0)
+ err(2, "open pagemap");
+
+ len -= len % HPAGE_SIZE;
+ ptr = mmap(NULL, len + HPAGE_SIZE, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE, -1, 0);
+ if (ptr == MAP_FAILED)
+ err(2, "initial mmap");
+ ptr += HPAGE_SIZE - (uintptr_t)ptr % HPAGE_SIZE;
+
+ if (madvise(ptr, len, MADV_HUGEPAGE))
+ err(2, "MADV_HUGEPAGE");
+
+ map_len = ram >> (HPAGE_SHIFT - 1);
+ map = malloc(map_len);
+ if (!map)
+ errx(2, "map malloc");
+
+ while (1) {
+ int nr_succeed = 0, nr_failed = 0, nr_pages = 0;
+
+ memset(map, 0, map_len);
+
+ clock_gettime(CLOCK_MONOTONIC, &a);
+ for (p = ptr; p < ptr + len; p += HPAGE_SIZE) {
+ int64_t pfn;
+
+ pfn = allocate_transhuge(p);
+
+ if (pfn < 0) {
+ nr_failed++;
+ } else {
+ size_t idx = pfn >> (HPAGE_SHIFT - PAGE_SHIFT);
+
+ nr_succeed++;
+ if (idx >= map_len) {
+ map = realloc(map, idx + 1);
+ if (!map)
+ errx(2, "map realloc");
+ memset(map + map_len, 0, idx + 1 - map_len);
+ map_len = idx + 1;
+ }
+ if (!map[idx])
+ nr_pages++;
+ map[idx] = 1;
+ }
+
+ /* split transhuge page, keep last page */
+ if (madvise(p, HPAGE_SIZE - PAGE_SIZE, MADV_DONTNEED))
+ err(2, "MADV_DONTNEED");
+ }
+ clock_gettime(CLOCK_MONOTONIC, &b);
+ s = b.tv_sec - a.tv_sec + (b.tv_nsec - a.tv_nsec) / 1000000000.;
+
+ warnx("%.3f s/loop, %.3f ms/page, %10.3f MiB/s\t"
+ "%4d succeed, %4d failed, %4d different pages",
+ s, s * 1000 / (len >> HPAGE_SHIFT), len / s / (1 << 20),
+ nr_succeed, nr_failed, nr_pages);
+ }
+}
--
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