selftests: vm: add KSM huge pages merging time test

Add test case of KSM merging time using mostly huge pages

Link: https://lkml.kernel.org/r/20211013044045.360251-1-pedrodemargomes@gmail.com
Signed-off-by: Pedro Demarchi Gomes <pedrodemargomes@gmail.com>
Cc: Zhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/tools/testing/selftests/vm/ksm_tests.c b/tools/testing/selftests/vm/ksm_tests.c
index 0e142d2..1436e1a 100644 (file)
--- a/tools/testing/selftests/vm/ksm_tests.c
+++ b/tools/testing/selftests/vm/ksm_tests.c
@@ -5,6 +5,10 @@
 #include <time.h>
 #include <string.h>
 #include <numa.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <err.h>
 
 #include "../kselftest.h"
 #include "../../../../include/vdso/time64.h"
@@ -18,6 +22,15 @@
 #define KSM_MERGE_ACROSS_NODES_DEFAULT true
 #define MB (1ul << 20)
 
+#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))
+
 struct ksm_sysfs {
        unsigned long max_page_sharing;
        unsigned long merge_across_nodes;
@@ -34,6 +47,7 @@ enum ksm_test_name {
        CHECK_KSM_ZERO_PAGE_MERGE,
        CHECK_KSM_NUMA_MERGE,
        KSM_MERGE_TIME,
+       KSM_MERGE_TIME_HUGE_PAGES,
        KSM_COW_TIME
 };
 
@@ -100,6 +114,9 @@ static void print_help(void)
               " -P evaluate merging time and speed.\n"
               "    For this test, the size of duplicated memory area (in MiB)\n"
               "    must be provided using -s option\n"
+                                " -H evaluate merging time and speed of area allocated mostly with huge pages\n"
+              "    For this test, the size of duplicated memory area (in MiB)\n"
+              "    must be provided using -s option\n"
               " -C evaluate the time required to break COW of merged pages.\n\n");
 
        printf(" -a: specify the access protections of pages.\n"
@@ -439,6 +456,101 @@ err_out:
        return KSFT_FAIL;
 }
 
+int64_t allocate_transhuge(void *ptr, int pagemap_fd)
+{
+       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;
+}
+
+static int ksm_merge_hugepages_time(int mapping, int prot, int timeout, size_t map_size)
+{
+       void *map_ptr, *map_ptr_orig;
+       struct timespec start_time, end_time;
+       unsigned long scan_time_ns;
+       int pagemap_fd, n_normal_pages, n_huge_pages;
+
+       map_size *= MB;
+       size_t len = map_size;
+
+       len -= len % HPAGE_SIZE;
+       map_ptr_orig = mmap(NULL, len + HPAGE_SIZE, PROT_READ | PROT_WRITE,
+                       MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE, -1, 0);
+       map_ptr = map_ptr_orig + HPAGE_SIZE - (uintptr_t)map_ptr_orig % HPAGE_SIZE;
+
+       if (map_ptr_orig == MAP_FAILED)
+               err(2, "initial mmap");
+
+       if (madvise(map_ptr, len + HPAGE_SIZE, MADV_HUGEPAGE))
+               err(2, "MADV_HUGEPAGE");
+
+       pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
+       if (pagemap_fd < 0)
+               err(2, "open pagemap");
+
+       n_normal_pages = 0;
+       n_huge_pages = 0;
+       for (void *p = map_ptr; p < map_ptr + len; p += HPAGE_SIZE) {
+               if (allocate_transhuge(p, pagemap_fd) < 0)
+                       n_normal_pages++;
+               else
+                       n_huge_pages++;
+       }
+       printf("Number of normal pages:    %d\n", n_normal_pages);
+       printf("Number of huge pages:    %d\n", n_huge_pages);
+
+       memset(map_ptr, '*', len);
+
+       if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) {
+               perror("clock_gettime");
+               goto err_out;
+       }
+       if (ksm_merge_pages(map_ptr, map_size, start_time, timeout))
+               goto err_out;
+       if (clock_gettime(CLOCK_MONOTONIC_RAW, &end_time)) {
+               perror("clock_gettime");
+               goto err_out;
+       }
+
+       scan_time_ns = (end_time.tv_sec - start_time.tv_sec) * NSEC_PER_SEC +
+                      (end_time.tv_nsec - start_time.tv_nsec);
+
+       printf("Total size:    %lu MiB\n", map_size / MB);
+       printf("Total time:    %ld.%09ld s\n", scan_time_ns / NSEC_PER_SEC,
+              scan_time_ns % NSEC_PER_SEC);
+       printf("Average speed:  %.3f MiB/s\n", (map_size / MB) /
+                                              ((double)scan_time_ns / NSEC_PER_SEC));
+
+       munmap(map_ptr_orig, len + HPAGE_SIZE);
+       return KSFT_PASS;
+
+err_out:
+       printf("Not OK\n");
+       munmap(map_ptr_orig, len + HPAGE_SIZE);
+       return KSFT_FAIL;
+}
+
 static int ksm_merge_time(int mapping, int prot, int timeout, size_t map_size)
 {
        void *map_ptr;
@@ -564,7 +676,7 @@ int main(int argc, char *argv[])
        bool merge_across_nodes = KSM_MERGE_ACROSS_NODES_DEFAULT;
        long size_MB = 0;
 
-       while ((opt = getopt(argc, argv, "ha:p:l:z:m:s:MUZNPC")) != -1) {
+       while ((opt = getopt(argc, argv, "ha:p:l:z:m:s:MUZNPCH")) != -1) {
                switch (opt) {
                case 'a':
                        prot = str_to_prot(optarg);
@@ -618,6 +730,9 @@ int main(int argc, char *argv[])
                case 'P':
                        test_name = KSM_MERGE_TIME;
                        break;
+               case 'H':
+                       test_name = KSM_MERGE_TIME_HUGE_PAGES;
+                       break;
                case 'C':
                        test_name = KSM_COW_TIME;
                        break;
@@ -670,6 +785,14 @@ int main(int argc, char *argv[])
                ret = ksm_merge_time(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec,
                                     size_MB);
                break;
+       case KSM_MERGE_TIME_HUGE_PAGES:
+               if (size_MB == 0) {
+                       printf("Option '-s' is required.\n");
+                       return KSFT_FAIL;
+               }
+               ret = ksm_merge_hugepages_time(MAP_PRIVATE | MAP_ANONYMOUS, prot,
+                               ksm_scan_limit_sec, size_MB);
+               break;
        case KSM_COW_TIME:
                ret = ksm_cow_time(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec,
                                   page_size);