[PATCH v24 12/14] mm/damon: Add kunit tests

SeongJae Park
2021-02-04T15:40:55Z

This commit adds kunit based unit tests for the core and the virtual
address spaces monitoring primitives of DAMON.

Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
---
mm/damon/Kconfig | 36 +++++
mm/damon/core-test.h | 253 ++++++++++++++++++++++++++++++++
mm/damon/core.c | 7 +
mm/damon/dbgfs-test.h | 214 +++++++++++++++++++++++++++
mm/damon/dbgfs.c | 2 +
mm/damon/vaddr-test.h | 328 ++++++++++++++++++++++++++++++++++++++++++
mm/damon/vaddr.c | 7 +
7 files changed, 847 insertions(+)
create mode 100644 mm/damon/core-test.h
create mode 100644 mm/damon/dbgfs-test.h
create mode 100644 mm/damon/vaddr-test.h

diff --git a/mm/damon/Kconfig b/mm/damon/Kconfig
index 72f1683ba0ee..455995152697 100644
--- a/mm/damon/Kconfig
+++ b/mm/damon/Kconfig
@@ -12,6 +12,18 @@ config DAMON
See https://damonitor.github.io/doc/html/latest-damon/index.html for
more information.

+config DAMON_KUNIT_TEST
+ bool "Test for damon" if !KUNIT_ALL_TESTS
+ depends on DAMON && KUNIT=y
+ default KUNIT_ALL_TESTS
+ help
+ This builds the DAMON Kunit test suite.
+
+ For more information on KUnit and unit tests in general, please refer
+ to the KUnit documentation.
+
+ If unsure, say N.
+
config DAMON_VADDR
bool "Data access monitoring primitives for virtual address spaces"
depends on DAMON && MMU
@@ -21,6 +33,18 @@ config DAMON_VADDR
This builds the default data access monitoring primitives for DAMON
that works for virtual address spaces.

+config DAMON_VADDR_KUNIT_TEST
+ bool "Test for DAMON primitives" if !KUNIT_ALL_TESTS
+ depends on DAMON_VADDR && KUNIT=y
+ default KUNIT_ALL_TESTS
+ help
+ This builds the DAMON virtual addresses primitives Kunit test suite.
+
+ For more information on KUnit and unit tests in general, please refer
+ to the KUnit documentation.
+
+ If unsure, say N.
+
config DAMON_DBGFS
bool "DAMON debugfs interface"
depends on DAMON_VADDR && DEBUG_FS
@@ -30,4 +54,16 @@ config DAMON_DBGFS

If unsure, say N.

+config DAMON_DBGFS_KUNIT_TEST
+ bool "Test for damon debugfs interface" if !KUNIT_ALL_TESTS
+ depends on DAMON_DBGFS && KUNIT=y
+ default KUNIT_ALL_TESTS
+ help
+ This builds the DAMON debugfs interface Kunit test suite.
+
+ For more information on KUnit and unit tests in general, please refer
+ to the KUnit documentation.
+
+ If unsure, say N.
+
endmenu
diff --git a/mm/damon/core-test.h b/mm/damon/core-test.h
new file mode 100644
index 000000000000..b815dfbfb5fd
--- /dev/null
+++ b/mm/damon/core-test.h
@@ -0,0 +1,253 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Data Access Monitor Unit Tests
+ *
+ * Copyright 2019 Amazon.com, Inc. or its affiliates. All rights reserved.
+ *
+ * Author: SeongJae Park <sjpark@amazon.de>
+ */
+
+#ifdef CONFIG_DAMON_KUNIT_TEST
+
+#ifndef _DAMON_CORE_TEST_H
+#define _DAMON_CORE_TEST_H
+
+#include <kunit/test.h>
+
+static void damon_test_regions(struct kunit *test)
+{
+ struct damon_region *r;
+ struct damon_target *t;
+
+ r = damon_new_region(1, 2);
+ KUNIT_EXPECT_EQ(test, 1ul, r->ar.start);
+ KUNIT_EXPECT_EQ(test, 2ul, r->ar.end);
+ KUNIT_EXPECT_EQ(test, 0u, r->nr_accesses);
+
+ t = damon_new_target(42);
+ KUNIT_EXPECT_EQ(test, 0u, damon_nr_regions(t));
+
+ damon_add_region(r, t);
+ KUNIT_EXPECT_EQ(test, 1u, damon_nr_regions(t));
+
+ damon_del_region(r);
+ KUNIT_EXPECT_EQ(test, 0u, damon_nr_regions(t));
+
+ damon_free_target(t);
+}
+
+static unsigned int nr_damon_targets(struct damon_ctx *ctx)
+{
+ struct damon_target *t;
+ unsigned int nr_targets = 0;
+
+ damon_for_each_target(t, ctx)
+ nr_targets++;
+
+ return nr_targets;
+}
+
+static void damon_test_target(struct kunit *test)
+{
+ struct damon_ctx *c = damon_new_ctx();
+ struct damon_target *t;
+
+ t = damon_new_target(42);
+ KUNIT_EXPECT_EQ(test, 42ul, t->id);
+ KUNIT_EXPECT_EQ(test, 0u, nr_damon_targets(c));
+
+ damon_add_target(c, t);
+ KUNIT_EXPECT_EQ(test, 1u, nr_damon_targets(c));
+
+ damon_destroy_target(t);
+ KUNIT_EXPECT_EQ(test, 0u, nr_damon_targets(c));
+
+ damon_destroy_ctx(c);
+}
+
+/*
+ * Test kdamond_reset_aggregated()
+ *
+ * DAMON checks access to each region and aggregates this information as the
+ * access frequency of each region. In detail, it increases '->nr_accesses' of
+ * regions that an access has confirmed. 'kdamond_reset_aggregated()' flushes
+ * the aggregated information ('->nr_accesses' of each regions) to the result
+ * buffer. As a result of the flushing, the '->nr_accesses' of regions are
+ * initialized to zero.
+ */
+static void damon_test_aggregate(struct kunit *test)
+{
+ struct damon_ctx *ctx = damon_new_ctx();
+ unsigned long target_ids[] = {1, 2, 3};
+ unsigned long saddr[][3] = {{10, 20, 30}, {5, 42, 49}, {13, 33, 55} };
+ unsigned long eaddr[][3] = {{15, 27, 40}, {31, 45, 55}, {23, 44, 66} };
+ unsigned long accesses[][3] = {{42, 95, 84}, {10, 20, 30}, {0, 1, 2} };
+ struct damon_target *t;
+ struct damon_region *r;
+ int it, ir;
+
+ damon_set_targets(ctx, target_ids, 3);
+
+ it = 0;
+ damon_for_each_target(t, ctx) {
+ for (ir = 0; ir < 3; ir++) {
+ r = damon_new_region(saddr[it][ir], eaddr[it][ir]);
+ r->nr_accesses = accesses[it][ir];
+ damon_add_region(r, t);
+ }
+ it++;
+ }
+ kdamond_reset_aggregated(ctx);
+ it = 0;
+ damon_for_each_target(t, ctx) {
+ ir = 0;
+ /* '->nr_accesses' should be zeroed */
+ damon_for_each_region(r, t) {
+ KUNIT_EXPECT_EQ(test, 0u, r->nr_accesses);
+ ir++;
+ }
+ /* regions should be preserved */
+ KUNIT_EXPECT_EQ(test, 3, ir);
+ it++;
+ }
+ /* targets also should be preserved */
+ KUNIT_EXPECT_EQ(test, 3, it);
+
+ damon_destroy_ctx(ctx);
+}
+
+static void damon_test_split_at(struct kunit *test)
+{
+ struct damon_ctx *c = damon_new_ctx();
+ struct damon_target *t;
+ struct damon_region *r;
+
+ t = damon_new_target(42);
+ r = damon_new_region(0, 100);
+ damon_add_region(r, t);
+ damon_split_region_at(c, r, 25);
+ KUNIT_EXPECT_EQ(test, r->ar.start, 0ul);
+ KUNIT_EXPECT_EQ(test, r->ar.end, 25ul);
+
+ r = damon_next_region(r);
+ KUNIT_EXPECT_EQ(test, r->ar.start, 25ul);
+ KUNIT_EXPECT_EQ(test, r->ar.end, 100ul);
+
+ damon_free_target(t);
+ damon_destroy_ctx(c);
+}
+
+static void damon_test_merge_two(struct kunit *test)
+{
+ struct damon_target *t;
+ struct damon_region *r, *r2, *r3;
+ int i;
+
+ t = damon_new_target(42);
+ r = damon_new_region(0, 100);
+ r->nr_accesses = 10;
+ damon_add_region(r, t);
+ r2 = damon_new_region(100, 300);
+ r2->nr_accesses = 20;
+ damon_add_region(r2, t);
+
+ damon_merge_two_regions(r, r2);
+ KUNIT_EXPECT_EQ(test, r->ar.start, 0ul);
+ KUNIT_EXPECT_EQ(test, r->ar.end, 300ul);
+ KUNIT_EXPECT_EQ(test, r->nr_accesses, 16u);
+
+ i = 0;
+ damon_for_each_region(r3, t) {
+ KUNIT_EXPECT_PTR_EQ(test, r, r3);
+ i++;
+ }
+ KUNIT_EXPECT_EQ(test, i, 1);
+
+ damon_free_target(t);
+}
+
+static struct damon_region *__nth_region_of(struct damon_target *t, int idx)
+{
+ struct damon_region *r;
+ unsigned int i = 0;
+
+ damon_for_each_region(r, t) {
+ if (i++ == idx)
+ return r;
+ }
+
+ return NULL;
+}
+
+static void damon_test_merge_regions_of(struct kunit *test)
+{
+ struct damon_target *t;
+ struct damon_region *r;
+ unsigned long sa[] = {0, 100, 114, 122, 130, 156, 170, 184};
+ unsigned long ea[] = {100, 112, 122, 130, 156, 170, 184, 230};
+ unsigned int nrs[] = {0, 0, 10, 10, 20, 30, 1, 2};
+
+ unsigned long saddrs[] = {0, 114, 130, 156, 170};
+ unsigned long eaddrs[] = {112, 130, 156, 170, 230};
+ int i;
+
+ t = damon_new_target(42);
+ for (i = 0; i < ARRAY_SIZE(sa); i++) {
+ r = damon_new_region(sa[i], ea[i]);
+ r->nr_accesses = nrs[i];
+ damon_add_region(r, t);
+ }
+
+ damon_merge_regions_of(t, 9, 9999);
+ /* 0-112, 114-130, 130-156, 156-170 */
+ KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 5u);
+ for (i = 0; i < 5; i++) {
+ r = __nth_region_of(t, i);
+ KUNIT_EXPECT_EQ(test, r->ar.start, saddrs[i]);
+ KUNIT_EXPECT_EQ(test, r->ar.end, eaddrs[i]);
+ }
+ damon_free_target(t);
+}
+
+static void damon_test_split_regions_of(struct kunit *test)
+{
+ struct damon_ctx *c = damon_new_ctx();
+ struct damon_target *t;
+ struct damon_region *r;
+
+ t = damon_new_target(42);
+ r = damon_new_region(0, 22);
+ damon_add_region(r, t);
+ damon_split_regions_of(c, t, 2);
+ KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 2u);
+ damon_free_target(t);
+
+ t = damon_new_target(42);
+ r = damon_new_region(0, 220);
+ damon_add_region(r, t);
+ damon_split_regions_of(c, t, 4);
+ KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 4u);
+ damon_free_target(t);
+ damon_destroy_ctx(c);
+}
+
+static struct kunit_case damon_test_cases[] = {
+ KUNIT_CASE(damon_test_target),
+ KUNIT_CASE(damon_test_regions),
+ KUNIT_CASE(damon_test_aggregate),
+ KUNIT_CASE(damon_test_split_at),
+ KUNIT_CASE(damon_test_merge_two),
+ KUNIT_CASE(damon_test_merge_regions_of),
+ KUNIT_CASE(damon_test_split_regions_of),
+ {},
+};
+
+static struct kunit_suite damon_test_suite = {
+ .name = "damon",
+ .test_cases = damon_test_cases,
+};
+kunit_test_suite(damon_test_suite);
+
+#endif /* _DAMON_CORE_TEST_H */
+
+#endif /* CONFIG_DAMON_KUNIT_TEST */
diff --git a/mm/damon/core.c b/mm/damon/core.c
index cad2b4cee39d..6bfb5d7d9142 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -16,6 +16,11 @@
#define CREATE_TRACE_POINTS
#include <trace/events/damon.h>

+#ifdef CONFIG_DAMON_KUNIT_TEST
+#undef DAMON_MIN_REGION
+#define DAMON_MIN_REGION 1
+#endif
+
/* Get a random number in [l, r) */
#define damon_rand(l, r) (l + prandom_u32_max(r - l))

@@ -709,3 +714,5 @@ static int kdamond_fn(void *data)

do_exit(0);
}
+
+#include "core-test.h"
diff --git a/mm/damon/dbgfs-test.h b/mm/damon/dbgfs-test.h
new file mode 100644
index 000000000000..ae6a23a95106
--- /dev/null
+++ b/mm/damon/dbgfs-test.h
@@ -0,0 +1,214 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * DAMON Debugfs Interface Unit Tests
+ *
+ * Author: SeongJae Park <sjpark@amazon.de>
+ */
+
+#ifdef CONFIG_DAMON_DBGFS_KUNIT_TEST
+
+#ifndef _DAMON_DBGFS_TEST_H
+#define _DAMON_DBGFS_TEST_H
+
+#include <kunit/test.h>
+
+static void damon_dbgfs_test_str_to_target_ids(struct kunit *test)
+{
+ char *question;
+ unsigned long *answers;
+ unsigned long expected[] = {12, 35, 46};
+ ssize_t nr_integers = 0, i;
+
+ question = "123";
+ answers = str_to_target_ids(question, strnlen(question, 128),
+ &nr_integers);
+ KUNIT_EXPECT_EQ(test, (ssize_t)1, nr_integers);
+ KUNIT_EXPECT_EQ(test, 123ul, answers[0]);
+ kfree(answers);
+
+ question = "123abc";
+ answers = str_to_target_ids(question, strnlen(question, 128),
+ &nr_integers);
+ KUNIT_EXPECT_EQ(test, (ssize_t)1, nr_integers);
+ KUNIT_EXPECT_EQ(test, 123ul, answers[0]);
+ kfree(answers);
+
+ question = "a123";
+ answers = str_to_target_ids(question, strnlen(question, 128),
+ &nr_integers);
+ KUNIT_EXPECT_EQ(test, (ssize_t)0, nr_integers);
+ kfree(answers);
+
+ question = "12 35";
+ answers = str_to_target_ids(question, strnlen(question, 128),
+ &nr_integers);
+ KUNIT_EXPECT_EQ(test, (ssize_t)2, nr_integers);
+ for (i = 0; i < nr_integers; i++)
+ KUNIT_EXPECT_EQ(test, expected[i], answers[i]);
+ kfree(answers);
+
+ question = "12 35 46";
+ answers = str_to_target_ids(question, strnlen(question, 128),
+ &nr_integers);
+ KUNIT_EXPECT_EQ(test, (ssize_t)3, nr_integers);
+ for (i = 0; i < nr_integers; i++)
+ KUNIT_EXPECT_EQ(test, expected[i], answers[i]);
+ kfree(answers);
+
+ question = "12 35 abc 46";
+ answers = str_to_target_ids(question, strnlen(question, 128),
+ &nr_integers);
+ KUNIT_EXPECT_EQ(test, (ssize_t)2, nr_integers);
+ for (i = 0; i < 2; i++)
+ KUNIT_EXPECT_EQ(test, expected[i], answers[i]);
+ kfree(answers);
+
+ question = "";
+ answers = str_to_target_ids(question, strnlen(question, 128),
+ &nr_integers);
+ KUNIT_EXPECT_EQ(test, (ssize_t)0, nr_integers);
+ kfree(answers);
+
+ question = "\n";
+ answers = str_to_target_ids(question, strnlen(question, 128),
+ &nr_integers);
+ KUNIT_EXPECT_EQ(test, (ssize_t)0, nr_integers);
+ kfree(answers);
+}
+
+static void damon_dbgfs_test_set_targets(struct kunit *test)
+{
+ struct damon_ctx *ctx = dbgfs_new_ctx();
+ unsigned long ids[] = {1, 2, 3};
+ char buf[64];
+
+ /* Make DAMON consider target id as plain number */
+ ctx->primitive.target_valid = NULL;
+ ctx->primitive.cleanup = NULL;
+
+ damon_set_targets(ctx, ids, 3);
+ sprint_target_ids(ctx, buf, 64);
+ KUNIT_EXPECT_STREQ(test, (char *)buf, "1 2 3\n");
+
+ damon_set_targets(ctx, NULL, 0);
+ sprint_target_ids(ctx, buf, 64);
+ KUNIT_EXPECT_STREQ(test, (char *)buf, "\n");
+
+ damon_set_targets(ctx, (unsigned long []){1, 2}, 2);
+ sprint_target_ids(ctx, buf, 64);
+ KUNIT_EXPECT_STREQ(test, (char *)buf, "1 2\n");
+
+ damon_set_targets(ctx, (unsigned long []){2}, 1);
+ sprint_target_ids(ctx, buf, 64);
+ KUNIT_EXPECT_STREQ(test, (char *)buf, "2\n");
+
+ damon_set_targets(ctx, NULL, 0);
+ sprint_target_ids(ctx, buf, 64);
+ KUNIT_EXPECT_STREQ(test, (char *)buf, "\n");
+
+ dbgfs_destroy_ctx(ctx);
+}
+
+static void damon_dbgfs_test_set_recording(struct kunit *test)
+{
+ struct damon_ctx *ctx = dbgfs_new_ctx();
+ struct dbgfs_recorder *rec = ctx->callback.private;
+ int err;
+
+ err = dbgfs_set_recording(ctx, 42, "foo");
+ KUNIT_EXPECT_EQ(test, err, -EINVAL);
+ dbgfs_set_recording(ctx, 4242, "foo.bar");
+ KUNIT_EXPECT_EQ(test, rec->rbuf_len, 4242u);
+ KUNIT_EXPECT_STREQ(test, rec->rfile_path, "foo.bar");
+ dbgfs_set_recording(ctx, 424242, "foo");
+ KUNIT_EXPECT_EQ(test, rec->rbuf_len, 424242u);
+ KUNIT_EXPECT_STREQ(test, rec->rfile_path, "foo");
+
+ dbgfs_destroy_ctx(ctx);
+}
+
+static void damon_dbgfs_test_write_rbuf(struct kunit *test)
+{
+ struct damon_ctx *ctx = dbgfs_new_ctx();
+ struct dbgfs_recorder *rec = ctx->callback.private;
+ char *data;
+
+ dbgfs_set_recording(ctx, 4242, "damon.data");
+
+ data = "hello";
+ dbgfs_write_rbuf(ctx, data, strnlen(data, 256));
+ KUNIT_EXPECT_EQ(test, rec->rbuf_offset, 5u);
+
+ dbgfs_write_rbuf(ctx, data, 0);
+ KUNIT_EXPECT_EQ(test, rec->rbuf_offset, 5u);
+
+ KUNIT_EXPECT_STREQ(test, (char *)rec->rbuf, data);
+
+ dbgfs_destroy_ctx(ctx);
+}
+
+/*
+ * Test dbgfs_after_aggregation()
+ *
+ * dbgfs sets dbgfs_after_aggregation() as aggregate callback. It stores the
+ * aggregated monitoring information ('->nr_accesses' of each regions) to the
+ * result buffer.
+ */
+static void damon_dbgfs_test_aggregate(struct kunit *test)
+{
+ struct damon_ctx *ctx = dbgfs_new_ctx();
+ struct dbgfs_recorder *rec = ctx->callback.private;
+ unsigned long target_ids[] = {1, 2, 3};
+ unsigned long saddr[][3] = {{10, 20, 30}, {5, 42, 49}, {13, 33, 55} };
+ unsigned long eaddr[][3] = {{15, 27, 40}, {31, 45, 55}, {23, 44, 66} };
+ unsigned long accesses[][3] = {{42, 95, 84}, {10, 20, 30}, {0, 1, 2} };
+ struct damon_target *t;
+ struct damon_region *r;
+ int it, ir;
+ ssize_t sz, sr, sp;
+
+ /* Make DAMON consider target id as plain number */
+ ctx->primitive.target_valid = NULL;
+ ctx->primitive.cleanup = NULL;
+
+ dbgfs_set_recording(ctx, 4242, "damon.data");
+ damon_set_targets(ctx, target_ids, 3);
+
+ it = 0;
+ damon_for_each_target(t, ctx) {
+ for (ir = 0; ir < 3; ir++) {
+ r = damon_new_region(saddr[it][ir], eaddr[it][ir]);
+ r->nr_accesses = accesses[it][ir];
+ damon_add_region(r, t);
+ }
+ it++;
+ }
+ dbgfs_after_aggregation(ctx);
+
+ /* The aggregated information should be written in the buffer */
+ sr = sizeof(r->ar.start) + sizeof(r->ar.end) + sizeof(r->nr_accesses);
+ sp = sizeof(t->id) + sizeof(unsigned int) + 3 * sr;
+ sz = sizeof(struct timespec64) + sizeof(unsigned int) + 3 * sp;
+ KUNIT_EXPECT_EQ(test, (unsigned int)sz, rec->rbuf_offset);
+
+ damon_destroy_ctx(ctx);
+}
+
+static struct kunit_case damon_test_cases[] = {
+ KUNIT_CASE(damon_dbgfs_test_str_to_target_ids),
+ KUNIT_CASE(damon_dbgfs_test_set_targets),
+ KUNIT_CASE(damon_dbgfs_test_set_recording),
+ KUNIT_CASE(damon_dbgfs_test_write_rbuf),
+ KUNIT_CASE(damon_dbgfs_test_aggregate),
+ {},
+};
+
+static struct kunit_suite damon_test_suite = {
+ .name = "damon-dbgfs",
+ .test_cases = damon_test_cases,
+};
+kunit_test_suite(damon_test_suite);
+
+#endif /* _DAMON_TEST_H */
+
+#endif /* CONFIG_DAMON_KUNIT_TEST */
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
index 68edfd4d3b41..bd803f1f90e6 100644
--- a/mm/damon/dbgfs.c
+++ b/mm/damon/dbgfs.c
@@ -884,3 +884,5 @@ static int __init damon_dbgfs_init(void)
}

module_init(damon_dbgfs_init);
+
+#include "dbgfs-test.h"
diff --git a/mm/damon/vaddr-test.h b/mm/damon/vaddr-test.h
new file mode 100644
index 000000000000..c9394e1d21d3
--- /dev/null
+++ b/mm/damon/vaddr-test.h
@@ -0,0 +1,328 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Data Access Monitor Unit Tests
+ *
+ * Copyright 2019 Amazon.com, Inc. or its affiliates. All rights reserved.
+ *
+ * Author: SeongJae Park <sjpark@amazon.de>
+ */
+
+#ifdef CONFIG_DAMON_VADDR_KUNIT_TEST
+
+#ifndef _DAMON_VADDR_TEST_H
+#define _DAMON_VADDR_TEST_H
+
+#include <kunit/test.h>
+
+static void __link_vmas(struct vm_area_struct *vmas, ssize_t nr_vmas)
+{
+ int i, j;
+ unsigned long largest_gap, gap;
+
+ if (!nr_vmas)
+ return;
+
+ for (i = 0; i < nr_vmas - 1; i++) {
+ vmas[i].vm_next = &vmas[i + 1];
+
+ vmas[i].vm_rb.rb_left = NULL;
+ vmas[i].vm_rb.rb_right = &vmas[i + 1].vm_rb;
+
+ largest_gap = 0;
+ for (j = i; j < nr_vmas; j++) {
+ if (j == 0)
+ continue;
+ gap = vmas[j].vm_start - vmas[j - 1].vm_end;
+ if (gap > largest_gap)
+ largest_gap = gap;
+ }
+ vmas[i].rb_subtree_gap = largest_gap;
+ }
+ vmas[i].vm_next = NULL;
+ vmas[i].vm_rb.rb_right = NULL;
+ vmas[i].rb_subtree_gap = 0;
+}
+
+/*
+ * Test __damon_va_three_regions() function
+ *
+ * In case of virtual memory address spaces monitoring, DAMON converts the
+ * complex and dynamic memory mappings of each target task to three
+ * discontiguous regions which cover every mapped areas. However, the three
+ * regions should not include the two biggest unmapped areas in the original
+ * mapping, because the two biggest areas are normally the areas between 1)
+ * heap and the mmap()-ed regions, and 2) the mmap()-ed regions and stack.
+ * Because these two unmapped areas are very huge but obviously never accessed,
+ * covering the region is just a waste.
+ *
+ * '__damon_va_three_regions() receives an address space of a process. It
+ * first identifies the start of mappings, end of mappings, and the two biggest
+ * unmapped areas. After that, based on the information, it constructs the
+ * three regions and returns. For more detail, refer to the comment of
+ * 'damon_init_regions_of()' function definition in 'mm/damon.c' file.
+ *
+ * For example, suppose virtual address ranges of 10-20, 20-25, 200-210,
+ * 210-220, 300-305, and 307-330 (Other comments represent this mappings in
+ * more short form: 10-20-25, 200-210-220, 300-305, 307-330) of a process are
+ * mapped. To cover every mappings, the three regions should start with 10,
+ * and end with 305. The process also has three unmapped areas, 25-200,
+ * 220-300, and 305-307. Among those, 25-200 and 220-300 are the biggest two
+ * unmapped areas, and thus it should be converted to three regions of 10-25,
+ * 200-220, and 300-330.
+ */
+static void damon_test_three_regions_in_vmas(struct kunit *test)
+{
+ struct damon_addr_range regions[3] = {0,};
+ /* 10-20-25, 200-210-220, 300-305, 307-330 */
+ struct vm_area_struct vmas[] = {
+ (struct vm_area_struct) {.vm_start = 10, .vm_end = 20},
+ (struct vm_area_struct) {.vm_start = 20, .vm_end = 25},
+ (struct vm_area_struct) {.vm_start = 200, .vm_end = 210},
+ (struct vm_area_struct) {.vm_start = 210, .vm_end = 220},
+ (struct vm_area_struct) {.vm_start = 300, .vm_end = 305},
+ (struct vm_area_struct) {.vm_start = 307, .vm_end = 330},
+ };
+
+ __link_vmas(vmas, 6);
+
+ __damon_va_three_regions(&vmas[0], regions);
+
+ KUNIT_EXPECT_EQ(test, 10ul, regions[0].start);
+ KUNIT_EXPECT_EQ(test, 25ul, regions[0].end);
+ KUNIT_EXPECT_EQ(test, 200ul, regions[1].start);
+ KUNIT_EXPECT_EQ(test, 220ul, regions[1].end);
+ KUNIT_EXPECT_EQ(test, 300ul, regions[2].start);
+ KUNIT_EXPECT_EQ(test, 330ul, regions[2].end);
+}
+
+static struct damon_region *__nth_region_of(struct damon_target *t, int idx)
+{
+ struct damon_region *r;
+ unsigned int i = 0;
+
+ damon_for_each_region(r, t) {
+ if (i++ == idx)
+ return r;
+ }
+
+ return NULL;
+}
+
+/*
+ * Test 'damon_va_apply_three_regions()'
+ *
+ * test kunit object
+ * regions an array containing start/end addresses of current
+ * monitoring target regions
+ * nr_regions the number of the addresses in 'regions'
+ * three_regions The three regions that need to be applied now
+ * expected start/end addresses of monitoring target regions that
+ * 'three_regions' are applied
+ * nr_expected the number of addresses in 'expected'
+ *
+ * The memory mapping of the target processes changes dynamically. To follow
+ * the change, DAMON periodically reads the mappings, simplifies it to the
+ * three regions, and updates the monitoring target regions to fit in the three
+ * regions. The update of current target regions is the role of
+ * 'damon_va_apply_three_regions()'.
+ *
+ * This test passes the given target regions and the new three regions that
+ * need to be applied to the function and check whether it updates the regions
+ * as expected.
+ */
+static void damon_do_test_apply_three_regions(struct kunit *test,
+ unsigned long *regions, int nr_regions,
+ struct damon_addr_range *three_regions,
+ unsigned long *expected, int nr_expected)
+{
+ struct damon_ctx *ctx = damon_new_ctx();
+ struct damon_target *t;
+ struct damon_region *r;
+ int i;
+
+ t = damon_new_target(42);
+ for (i = 0; i < nr_regions / 2; i++) {
+ r = damon_new_region(regions[i * 2], regions[i * 2 + 1]);
+ damon_add_region(r, t);
+ }
+ damon_add_target(ctx, t);
+
+ damon_va_apply_three_regions(ctx, t, three_regions);
+
+ for (i = 0; i < nr_expected / 2; i++) {
+ r = __nth_region_of(t, i);
+ KUNIT_EXPECT_EQ(test, r->ar.start, expected[i * 2]);
+ KUNIT_EXPECT_EQ(test, r->ar.end, expected[i * 2 + 1]);
+ }
+
+ damon_destroy_ctx(ctx);
+}
+
+/*
+ * This function test most common case where the three big regions are only
+ * slightly changed. Target regions should adjust their boundary (10-20-30,
+ * 50-55, 70-80, 90-100) to fit with the new big regions or remove target
+ * regions (57-79) that now out of the three regions.
+ */
+static void damon_test_apply_three_regions1(struct kunit *test)
+{
+ /* 10-20-30, 50-55-57-59, 70-80-90-100 */
+ unsigned long regions[] = {10, 20, 20, 30, 50, 55, 55, 57, 57, 59,
+ 70, 80, 80, 90, 90, 100};
+ /* 5-27, 45-55, 73-104 */
+ struct damon_addr_range new_three_regions[3] = {
+ (struct damon_addr_range){.start = 5, .end = 27},
+ (struct damon_addr_range){.start = 45, .end = 55},
+ (struct damon_addr_range){.start = 73, .end = 104} };
+ /* 5-20-27, 45-55, 73-80-90-104 */
+ unsigned long expected[] = {5, 20, 20, 27, 45, 55,
+ 73, 80, 80, 90, 90, 104};
+
+ damon_do_test_apply_three_regions(test, regions, ARRAY_SIZE(regions),
+ new_three_regions, expected, ARRAY_SIZE(expected));
+}
+
+/*
+ * Test slightly bigger change. Similar to above, but the second big region
+ * now require two target regions (50-55, 57-59) to be removed.
+ */
+static void damon_test_apply_three_regions2(struct kunit *test)
+{
+ /* 10-20-30, 50-55-57-59, 70-80-90-100 */
+ unsigned long regions[] = {10, 20, 20, 30, 50, 55, 55, 57, 57, 59,
+ 70, 80, 80, 90, 90, 100};
+ /* 5-27, 56-57, 65-104 */
+ struct damon_addr_range new_three_regions[3] = {
+ (struct damon_addr_range){.start = 5, .end = 27},
+ (struct damon_addr_range){.start = 56, .end = 57},
+ (struct damon_addr_range){.start = 65, .end = 104} };
+ /* 5-20-27, 56-57, 65-80-90-104 */
+ unsigned long expected[] = {5, 20, 20, 27, 56, 57,
+ 65, 80, 80, 90, 90, 104};
+
+ damon_do_test_apply_three_regions(test, regions, ARRAY_SIZE(regions),
+ new_three_regions, expected, ARRAY_SIZE(expected));
+}
+
+/*
+ * Test a big change. The second big region has totally freed and mapped to
+ * different area (50-59 -> 61-63). The target regions which were in the old
+ * second big region (50-55-57-59) should be removed and new target region
+ * covering the second big region (61-63) should be created.
+ */
+static void damon_test_apply_three_regions3(struct kunit *test)
+{
+ /* 10-20-30, 50-55-57-59, 70-80-90-100 */
+ unsigned long regions[] = {10, 20, 20, 30, 50, 55, 55, 57, 57, 59,
+ 70, 80, 80, 90, 90, 100};
+ /* 5-27, 61-63, 65-104 */
+ struct damon_addr_range new_three_regions[3] = {
+ (struct damon_addr_range){.start = 5, .end = 27},
+ (struct damon_addr_range){.start = 61, .end = 63},
+ (struct damon_addr_range){.start = 65, .end = 104} };
+ /* 5-20-27, 61-63, 65-80-90-104 */
+ unsigned long expected[] = {5, 20, 20, 27, 61, 63,
+ 65, 80, 80, 90, 90, 104};
+
+ damon_do_test_apply_three_regions(test, regions, ARRAY_SIZE(regions),
+ new_three_regions, expected, ARRAY_SIZE(expected));
+}
+
+/*
+ * Test another big change. Both of the second and third big regions (50-59
+ * and 70-100) has totally freed and mapped to different area (30-32 and
+ * 65-68). The target regions which were in the old second and third big
+ * regions should now be removed and new target regions covering the new second
+ * and third big regions should be crated.
+ */
+static void damon_test_apply_three_regions4(struct kunit *test)
+{
+ /* 10-20-30, 50-55-57-59, 70-80-90-100 */
+ unsigned long regions[] = {10, 20, 20, 30, 50, 55, 55, 57, 57, 59,
+ 70, 80, 80, 90, 90, 100};
+ /* 5-7, 30-32, 65-68 */
+ struct damon_addr_range new_three_regions[3] = {
+ (struct damon_addr_range){.start = 5, .end = 7},
+ (struct damon_addr_range){.start = 30, .end = 32},
+ (struct damon_addr_range){.start = 65, .end = 68} };
+ /* expect 5-7, 30-32, 65-68 */
+ unsigned long expected[] = {5, 7, 30, 32, 65, 68};
+
+ damon_do_test_apply_three_regions(test, regions, ARRAY_SIZE(regions),
+ new_three_regions, expected, ARRAY_SIZE(expected));
+}
+
+static void damon_test_split_evenly(struct kunit *test)
+{
+ struct damon_ctx *c = damon_new_ctx();
+ struct damon_target *t;
+ struct damon_region *r;
+ unsigned long i;
+
+ KUNIT_EXPECT_EQ(test, damon_va_evenly_split_region(c, NULL, 5), -EINVAL);
+
+ t = damon_new_target(42);
+ r = damon_new_region(0, 100);
+ KUNIT_EXPECT_EQ(test, damon_va_evenly_split_region(c, r, 0), -EINVAL);
+
+ damon_add_region(r, t);
+ KUNIT_EXPECT_EQ(test, damon_va_evenly_split_region(c, r, 10), 0);
+ KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 10u);
+
+ i = 0;
+ damon_for_each_region(r, t) {
+ KUNIT_EXPECT_EQ(test, r->ar.start, i++ * 10);
+ KUNIT_EXPECT_EQ(test, r->ar.end, i * 10);
+ }
+ damon_free_target(t);
+
+ t = damon_new_target(42);
+ r = damon_new_region(5, 59);
+ damon_add_region(r, t);
+ KUNIT_EXPECT_EQ(test, damon_va_evenly_split_region(c, r, 5), 0);
+ KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 5u);
+
+ i = 0;
+ damon_for_each_region(r, t) {
+ if (i == 4)
+ break;
+ KUNIT_EXPECT_EQ(test, r->ar.start, 5 + 10 * i++);
+ KUNIT_EXPECT_EQ(test, r->ar.end, 5 + 10 * i);
+ }
+ KUNIT_EXPECT_EQ(test, r->ar.start, 5 + 10 * i);
+ KUNIT_EXPECT_EQ(test, r->ar.end, 59ul);
+ damon_free_target(t);
+
+ t = damon_new_target(42);
+ r = damon_new_region(5, 6);
+ damon_add_region(r, t);
+ KUNIT_EXPECT_EQ(test, damon_va_evenly_split_region(c, r, 2), -EINVAL);
+ KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 1u);
+
+ damon_for_each_region(r, t) {
+ KUNIT_EXPECT_EQ(test, r->ar.start, 5ul);
+ KUNIT_EXPECT_EQ(test, r->ar.end, 6ul);
+ }
+ damon_free_target(t);
+ damon_destroy_ctx(c);
+}
+
+static struct kunit_case damon_test_cases[] = {
+ KUNIT_CASE(damon_test_three_regions_in_vmas),
+ KUNIT_CASE(damon_test_apply_three_regions1),
+ KUNIT_CASE(damon_test_apply_three_regions2),
+ KUNIT_CASE(damon_test_apply_three_regions3),
+ KUNIT_CASE(damon_test_apply_three_regions4),
+ KUNIT_CASE(damon_test_split_evenly),
+ {},
+};
+
+static struct kunit_suite damon_test_suite = {
+ .name = "damon-primitives",
+ .test_cases = damon_test_cases,
+};
+kunit_test_suite(damon_test_suite);
+
+#endif /* _DAMON_VADDR_TEST_H */
+
+#endif /* CONFIG_DAMON_VADDR_KUNIT_TEST */
diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index a6bf234daae6..ebdb2ab7d681 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -15,6 +15,11 @@
#include <linux/sched/mm.h>
#include <linux/slab.h>

+#ifdef CONFIG_DAMON_VADDR_KUNIT_TEST
+#undef DAMON_MIN_REGION
+#define DAMON_MIN_REGION 1
+#endif
+
/* Get a random number in [l, r) */
#define damon_rand(l, r) (l + prandom_u32_max(r - l))

@@ -577,3 +582,5 @@ void damon_va_set_primitives(struct damon_ctx *ctx)
ctx->primitive.target_valid = damon_va_target_valid;
ctx->primitive.cleanup = damon_va_cleanup;
}
+
+#include "vaddr-test.h"
--
2.17.1