[LTP] [PATCH 04/29] Hugetlb: Migrating libhugetlbfs counters

[Tarun Sahu <tsahu@linux.ibm.com>]

Migrating the libhugetlbfs/testcases/counters.c test

Test Description: This Test perform mmap and unmap and write operation on
hugetlb file based mapping. Mapping can be shared or private. and it
checks for Hugetlb counter (Total, Free, Reserve, Surplus) in /proc/meminfo
and compare them with expected (calculated) value. if all checks are
successful, the test passes.

Signed-off-by: Tarun Sahu <tsahu@linux.ibm.com>
---
 runtest/hugetlb                               |   1 +
 testcases/kernel/mem/.gitignore               |   1 +
 .../kernel/mem/hugetlb/hugemmap/hugemmap10.c  | 475 ++++++++++++++++++
 3 files changed, 477 insertions(+)
 create mode 100644 testcases/kernel/mem/hugetlb/hugemmap/hugemmap10.c

diff --git a/runtest/hugetlb b/runtest/hugetlb
index e2ada7a97..8a56d52a3 100644
--- a/runtest/hugetlb
+++ b/runtest/hugetlb
@@ -6,6 +6,7 @@ hugemmap06 hugemmap06
 hugemmap07 hugemmap07
 hugemmap08 hugemmap08
 hugemmap09 hugemmap09
+hugemmap10 hugemmap10
 hugemmap05_1 hugemmap05 -m
 hugemmap05_2 hugemmap05 -s
 hugemmap05_3 hugemmap05 -s -m
diff --git a/testcases/kernel/mem/.gitignore b/testcases/kernel/mem/.gitignore
index 1a242ffe0..e7def68cb 100644
--- a/testcases/kernel/mem/.gitignore
+++ b/testcases/kernel/mem/.gitignore
@@ -7,6 +7,7 @@
 /hugetlb/hugemmap/hugemmap07
 /hugetlb/hugemmap/hugemmap08
 /hugetlb/hugemmap/hugemmap09
+/hugetlb/hugemmap/hugemmap10
 /hugetlb/hugeshmat/hugeshmat01
 /hugetlb/hugeshmat/hugeshmat02
 /hugetlb/hugeshmat/hugeshmat03
diff --git a/testcases/kernel/mem/hugetlb/hugemmap/hugemmap10.c b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap10.c
new file mode 100644
index 000000000..107add669
--- /dev/null
+++ b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap10.c
@@ -0,0 +1,475 @@
+// SPDX-License-Identifier: LGPL-2.1-or-later
+/*
+ * Copyright (C) 2005-2007 David Gibson & Adam Litke, IBM Corporation.
+ *
+ * Test Name: Counters
+ *
+ * Test Description: This Test perform mmap and unmap and write operation on
+ * hugetlb file based mapping. Mapping can be shared or private. and it checks
+ * for Hugetlb counter (Total, Free, Reserve, Surplus) in /proc/meminfo and
+ * compare them with expected (calculated) value. if all checks are successful,
+ * the test passes.
+ *
+ * HISTORY
+ *  Written by David Gibson & Adam Litke
+ *
+ */
+
+#define _GNU_SOURCE
+#include <unistd.h>
+#include <stdio.h>
+#include <sys/mount.h>
+#include <limits.h>
+#include <sys/param.h>
+#include <sys/types.h>
+
+#include "hugetlb.h"
+
+
+/* Global test configuration */
+#define PROC_NR_HUGEPAGES "/proc/sys/vm/nr_hugepages"
+#define PROC_OVERCOMMIT "/proc/sys/vm/nr_overcommit_hugepages"
+static long saved_nr_hugepages = -1;
+static long saved_oc_hugepages = -1;
+static long hpage_size;
+static int private_resv;
+static char *verbose;
+
+/* State arrays for our mmaps */
+#define NR_SLOTS	2
+#define SL_SETUP	0
+#define SL_TEST		1
+static char hfile[NR_SLOTS][MAXPATHLEN];
+static int map_fd[NR_SLOTS];
+static char *map_addr[NR_SLOTS];
+static unsigned long map_size[NR_SLOTS];
+static unsigned int touched[NR_SLOTS];
+
+/* Keep track of expected counter values */
+static long prev_total;
+static long prev_free;
+static long prev_resv;
+static long prev_surp;
+
+#define min(a, b) (((a) < (b)) ? (a) : (b))
+#define max(a, b) (((a) > (b)) ? (a) : (b))
+
+static void read_meminfo_huge(long *total, long *free, long *resv, long *surp)
+{
+	*total = SAFE_READ_MEMINFO("HugePages_Total:");
+	*free = SAFE_READ_MEMINFO("HugePages_Free:");
+	*resv = SAFE_READ_MEMINFO("HugePages_Rsvd:");
+	*surp = SAFE_READ_MEMINFO("HugePages_Surp:");
+}
+
+static int kernel_has_private_reservations(void)
+{
+	int fd;
+	long t, f, r, s;
+	long nt, nf, nr, ns;
+	void *map;
+
+	/* Read pool counters */
+	read_meminfo_huge(&t, &f, &r, &s);
+
+	fd = SAFE_OPEN(hfile[0], O_RDWR | O_CREAT, 0600);
+	SAFE_UNLINK(hfile[0]);
+	map = SAFE_MMAP(NULL, hpage_size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
+
+	/* Recheck the counters */
+	read_meminfo_huge(&nt, &nf, &nr, &ns);
+
+	SAFE_MUNMAP(map, hpage_size);
+	SAFE_CLOSE(fd);
+
+	/*
+	 * There are only three valid cases:
+	 * 1) If a surplus page was allocated to create a reservation, all
+	 *    four pool counters increment
+	 * 2) All counters remain the same except for Hugepages_Rsvd, then
+	 *    a reservation was created using an existing pool page.
+	 * 3) All counters remain the same, indicates that no reservation has
+	 *    been created
+	 */
+	if ((nt == t + 1) && (nf == f + 1) && (ns == s + 1) && (nr == r + 1)) {
+		return 1;
+	} else if ((nt == t) && (nf == f) && (ns == s)) {
+		if (nr == r + 1)
+			return 1;
+		else if (nr == r)
+			return 0;
+	} else {
+		tst_brk(TCONF, "%s: bad counter state - "
+		      "T:%li F:%li R:%li S:%li -> T:%li F:%li R:%li S:%li\n",
+			__func__, t, f, r, s, nt, nf, nr, ns);
+	}
+	return -1;
+}
+
+static void bad_value(int line, const char *name, long expect, long actual)
+{
+	tst_res(TFAIL, "Failure Line %i: Bad %s: expected %li, actual %li",
+			line, name, expect, actual);
+	tst_brk(TBROK, "Breaking.. as once one of counter is not expected, "
+			"it will cause other failure anyway");
+}
+
+static void verify_counters(int line, long et, long ef, long er, long es)
+{
+	long t, f, r, s;
+
+	/* Read pool counters */
+	read_meminfo_huge(&t, &f, &r, &s);
+
+	if (f < r)
+		tst_res(TWARN, "HugePages_Free < HugePages_Rsvd");
+
+	/* Check actual values against expected values */
+	if (t != et)
+		bad_value(line, "HugePages_Total", et, t);
+
+	if (f != ef)
+		bad_value(line, "HugePages_Free", ef, f);
+
+	if (r != er)
+		bad_value(line, "HugePages_Rsvd", er, r);
+
+	if (s != es)
+		bad_value(line, "HugePages_Surp", es, s);
+
+	/* Everything's good.  Update counters */
+	prev_total = t;
+	prev_free = f;
+	prev_resv = r;
+	prev_surp = s;
+}
+
+/* Memory operations:
+ * Each of these has a predefined effect on the counters
+ */
+#define persistent_huge_pages (et - es)
+static void _set_nr_hugepages(long count, int line)
+{
+	long min_size;
+	long et, ef, er, es;
+
+	SAFE_FILE_PRINTF(PROC_NR_HUGEPAGES, "%lu", count);
+
+	/* The code below is based on set_max_huge_pages in mm/hugetlb.c */
+	es = prev_surp;
+	et = prev_total;
+	ef = prev_free;
+	er = prev_resv;
+
+	/*
+	 * Increase the pool size
+	 * First take pages out of surplus state.  Then make up the
+	 * remaining difference by allocating fresh huge pages.
+	 */
+	while (es && count > persistent_huge_pages)
+		es--;
+	while (count > persistent_huge_pages) {
+		et++;
+		ef++;
+	}
+	if (count >= persistent_huge_pages)
+		goto out;
+
+	/*
+	 * Decrease the pool size
+	 * First return free pages to the buddy allocator (being careful
+	 * to keep enough around to satisfy reservations).  Then place
+	 * pages into surplus state as needed so the pool will shrink
+	 * to the desired size as pages become free.
+	 */
+	min_size = MAX(count, er + et - ef);
+	while (min_size < persistent_huge_pages) {
+		ef--;
+		et--;
+	}
+	while (count < persistent_huge_pages)
+		es++;
+
+out:
+	verify_counters(line, et, ef, er, es);
+}
+#define set_nr_hugepages(c) _set_nr_hugepages(c, __LINE__)
+
+static void _map(int s, int hpages, int flags, int line)
+{
+	long et, ef, er, es;
+
+	map_fd[s] = SAFE_OPEN(hfile[s], O_RDWR | O_CREAT, 0600);
+	SAFE_UNLINK(hfile[s]);
+	map_size[s] = hpages * hpage_size;
+	map_addr[s] = SAFE_MMAP(NULL, map_size[s], PROT_READ|PROT_WRITE, flags,
+				map_fd[s], 0);
+	touched[s] = 0;
+
+	et = prev_total;
+	ef = prev_free;
+	er = prev_resv;
+	es = prev_surp;
+
+	/*
+	 * When using MAP_SHARED, a reservation will be created to guarantee
+	 * pages to the process.  If not enough pages are available to
+	 * satisfy the reservation, surplus pages are added to the pool.
+	 * NOTE: This code assumes that the whole mapping needs to be
+	 * reserved and hence, will not work with partial reservations.
+	 *
+	 * If the kernel supports private reservations, then MAP_PRIVATE
+	 * mappings behave like MAP_SHARED at mmap time.  Otherwise,
+	 * no counter updates will occur.
+	 */
+	if ((flags & MAP_SHARED) || private_resv) {
+		unsigned long shortfall = 0;
+
+		if (hpages + prev_resv > prev_free)
+			shortfall = hpages - prev_free + prev_resv;
+		et += shortfall;
+		ef = prev_free + shortfall;
+		er = prev_resv + hpages;
+		es = prev_surp + shortfall;
+	}
+
+	verify_counters(line, et, ef, er, es);
+}
+#define map(s, h, f) _map(s, h, f, __LINE__)
+
+static void _unmap(int s, int hpages, int flags, int line)
+{
+	long et, ef, er, es;
+	unsigned long i;
+
+	SAFE_MUNMAP(map_addr[s], map_size[s]);
+	SAFE_CLOSE(map_fd[s]);
+	map_addr[s] = NULL;
+	map_size[s] = 0;
+
+	et = prev_total;
+	ef = prev_free;
+	er = prev_resv;
+	es = prev_surp;
+
+	/*
+	 * When a VMA is unmapped, the instantiated (touched) pages are
+	 * freed.  If the pool is in a surplus state, pages are freed to the
+	 * buddy allocator, otherwise they go back into the hugetlb pool.
+	 * NOTE: This code assumes touched pages have only one user.
+	 */
+	for (i = 0; i < touched[s]; i++) {
+		if (es) {
+			et--;
+			es--;
+		} else
+			ef++;
+	}
+
+	/*
+	 * mmap may have created some surplus pages to accommodate a
+	 * reservation.  If those pages were not touched, then they will
+	 * not have been freed by the code above.  Free them here.
+	 */
+	if ((flags & MAP_SHARED) || private_resv) {
+		int unused_surplus = MIN(hpages - touched[s], es);
+
+		et -= unused_surplus;
+		ef -= unused_surplus;
+		er -= hpages - touched[s];
+		es -= unused_surplus;
+	}
+
+	verify_counters(line, et, ef, er, es);
+}
+#define unmap(s, h, f) _unmap(s, h, f, __LINE__)
+
+static void _touch(int s, int hpages, int flags, int line)
+{
+	long et, ef, er, es;
+	int nr;
+	char *c;
+
+	for (c = map_addr[s], nr = hpages;
+			hpages && c < map_addr[s] + map_size[s];
+			c += hpage_size, nr--)
+		*c = (char) (nr % 2);
+	/*
+	 * Keep track of how many pages were touched since we can't easily
+	 * detect that from user space.
+	 * NOTE: Calling this function more than once for a mmap may yield
+	 * results you don't expect.  Be careful :)
+	 */
+	touched[s] = MAX(touched[s], hpages);
+
+	/*
+	 * Shared (and private when supported) mappings and consume resv pages
+	 * that were previously allocated. Also deduct them from the free count.
+	 *
+	 * Unreserved private mappings may need to allocate surplus pages to
+	 * satisfy the fault.  The surplus pages become part of the pool
+	 * which could elevate total, free, and surplus counts.  resv is
+	 * unchanged but free must be decreased.
+	 */
+	if (flags & MAP_SHARED || private_resv) {
+		et = prev_total;
+		ef = prev_free - hpages;
+		er = prev_resv - hpages;
+		es = prev_surp;
+	} else {
+		if (hpages + prev_resv > prev_free)
+			et = prev_total + (hpages - prev_free + prev_resv);
+		else
+			et = prev_total;
+		er = prev_resv;
+		es = prev_surp + et - prev_total;
+		ef = prev_free - hpages + et - prev_total;
+	}
+	verify_counters(line, et, ef, er, es);
+}
+#define touch(s, h, f) _touch(s, h, f, __LINE__)
+
+static void test_counters(char *desc, int base_nr)
+{
+	if (verbose)
+		tst_res(TINFO, "%s...", desc);
+	set_nr_hugepages(base_nr);
+
+	/* untouched, shared mmap */
+	map(SL_TEST, 1, MAP_SHARED);
+	unmap(SL_TEST, 1, MAP_SHARED);
+
+	/* untouched, private mmap */
+	map(SL_TEST, 1, MAP_PRIVATE);
+	unmap(SL_TEST, 1, MAP_PRIVATE);
+
+	/* touched, shared mmap */
+	map(SL_TEST, 1, MAP_SHARED);
+	touch(SL_TEST, 1, MAP_SHARED);
+	unmap(SL_TEST, 1, MAP_SHARED);
+
+	/* touched, private mmap */
+	map(SL_TEST, 1, MAP_PRIVATE);
+	touch(SL_TEST, 1, MAP_PRIVATE);
+	unmap(SL_TEST, 1, MAP_PRIVATE);
+
+	/* Explicit resizing during outstanding surplus */
+	/* Consume surplus when growing pool */
+	map(SL_TEST, 2, MAP_SHARED);
+	set_nr_hugepages(max(base_nr, 1));
+
+	/* Add pages once surplus is consumed */
+	set_nr_hugepages(max(base_nr, 3));
+
+	/* Release free huge pages first */
+	set_nr_hugepages(max(base_nr, 2));
+
+	/* When shrinking beyond committed level, increase surplus */
+	set_nr_hugepages(base_nr);
+
+	/* Upon releasing the reservation, reduce surplus counts */
+	unmap(SL_TEST, 2, MAP_SHARED);
+	if (verbose)
+		tst_res(TINFO, "OK");
+}
+
+static void per_iteration_cleanup(void)
+{
+	for (int nr = 0; nr < NR_SLOTS; nr++) {
+		if (map_fd[nr] >= 0)
+			SAFE_CLOSE(map_fd[nr]);
+	}
+	if (hpage_size <= 0)
+		return;
+	if (saved_nr_hugepages >= 0)
+		SAFE_FILE_PRINTF(PROC_NR_HUGEPAGES, "%ld", saved_nr_hugepages);
+	if (saved_oc_hugepages >= 0)
+		SAFE_FILE_PRINTF(PROC_OVERCOMMIT, "%ld", saved_oc_hugepages);
+}
+
+static void run_test(void)
+{
+	int base_nr = 0;
+
+	saved_nr_hugepages = SAFE_READ_MEMINFO("HugePages_Total:");
+
+	/* Verify Dynamic Pool support */
+	SAFE_FILE_LINES_SCANF(PROC_OVERCOMMIT, "%ld", &saved_oc_hugepages);
+	if (saved_oc_hugepages < 0)
+		tst_brk(TCONF, "Kernel appears to lack dynamic hugetlb pool support");
+
+	SAFE_FILE_PRINTF(PROC_OVERCOMMIT, "%d", 3);
+
+	private_resv = kernel_has_private_reservations();
+	/*
+	 * This test case should require a maximum of 3 huge pages.
+	 * Run through the battery of tests multiple times, with an increasing
+	 * base pool size.  This alters the circumstances under which surplus
+	 * pages need to be allocated and increases the corner cases tested.
+	 */
+	for (base_nr = 0; base_nr <= 3; base_nr++) {
+		if (verbose)
+			tst_res(TINFO, "Base pool size: %i", base_nr);
+		/* Run the tests with a clean slate */
+		test_counters("Clean", base_nr);
+
+		/* Now with a pre-existing untouched, shared mmap */
+		map(SL_SETUP, 1, MAP_SHARED);
+		test_counters("Untouched, shared", base_nr);
+		unmap(SL_SETUP, 1, MAP_SHARED);
+
+		/* Now with a pre-existing untouched, private mmap */
+		map(SL_SETUP, 1, MAP_PRIVATE);
+		test_counters("Untouched, private", base_nr);
+		unmap(SL_SETUP, 1, MAP_PRIVATE);
+
+		/* Now with a pre-existing touched, shared mmap */
+		map(SL_SETUP, 1, MAP_SHARED);
+		touch(SL_SETUP, 1, MAP_SHARED);
+		test_counters("Touched, shared", base_nr);
+		unmap(SL_SETUP, 1, MAP_SHARED);
+
+		/* Now with a pre-existing touched, private mmap */
+		map(SL_SETUP, 1, MAP_PRIVATE);
+		touch(SL_SETUP, 1, MAP_PRIVATE);
+		test_counters("Touched, private", base_nr);
+		unmap(SL_SETUP, 1, MAP_PRIVATE);
+	}
+	tst_res(TPASS, "Hugepages Counters works as expected.");
+	per_iteration_cleanup();
+}
+
+static void setup(void)
+{
+	if (!Hopt)
+		Hopt = tst_get_tmpdir();
+	SAFE_MOUNT("none", Hopt, "hugetlbfs", 0, NULL);
+	for (int nr = 0; nr < NR_SLOTS; nr++) {
+		snprintf(hfile[nr], sizeof(hfile[nr]), "%s/ltp_hugetlbfile%d_%d",
+				Hopt, getpid(), nr);
+	}
+
+	hpage_size = SAFE_READ_MEMINFO("Hugepagesize:")*1024;
+}
+
+static void cleanup(void)
+{
+	per_iteration_cleanup();
+	umount2(Hopt, MNT_DETACH);
+}
+
+static struct tst_test test = {
+	.needs_root = 1,
+	.needs_tmpdir = 1,
+	.options = (struct tst_option[]) {
+		{"v", &verbose, "Turns on verbose mode"},
+		{"H:", &Hopt,   "Location of hugetlbfs, i.e.  -H /var/hugetlbfs"},
+		{"s:", &nr_opt, "Set the number of the been allocated hugepages"},
+		{}
+	},
+	.setup = setup,
+	.cleanup = cleanup,
+	.test_all = run_test,
+	.hugepages = {0, TST_REQUEST},
+};
+
-- 
2.31.1


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