On Tue, Dec 27, 2022 at 9:00 PM Daniel Latypov dlatypov@google.com wrote:
On Mon, Dec 19, 2022 at 7:16 PM Rae Moar rmoar@google.com wrote:
Add a KUnit test for the kernel hashtable implementation in include/linux/hashtable.h.
Note that this version does not yet test each of the rcu alternative versions of functions.
Signed-off-by: Rae Moar rmoar@google.com
Looks pretty good from a cursory glance. Had some mostly stylistic nits/suggestions below.
Note: The check patch script is outputting open brace errors on lines 154, 186, 231 of lib/hashtable_test.c but I believe the format of the braces on those lines is consistent with the Linux Kernel style guide. Will continue to look at these errors.
lib/Kconfig.debug | 13 ++ lib/Makefile | 1 + lib/hashtable_test.c | 299 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 313 insertions(+) create mode 100644 lib/hashtable_test.c
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 3fc7abffc7aa..3cf3b6f8cff4 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2458,6 +2458,19 @@ config LIST_KUNIT_TEST
If unsure, say N.
+config HASHTABLE_KUNIT_TEST
tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
depends on KUNIT
default KUNIT_ALL_TESTS
help
This builds the hashtable KUnit test suite.
It tests the API and basic functionality of the functions
and associated macros defined in include/linux/hashtable.h.
nit: the "functions and associated macros" == "the API", so perhaps we can shorten this a bit.
This seems better to me. Thanks!
For more information on KUnit and unit tests in general please refer
to the KUnit documentation in Documentation/dev-tools/kunit/.
If unsure, say N.
config LINEAR_RANGES_TEST tristate "KUnit test for linear_ranges" depends on KUNIT diff --git a/lib/Makefile b/lib/Makefile index 161d6a724ff7..9036d3aeee0a 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -370,6 +370,7 @@ obj-$(CONFIG_PLDMFW) += pldmfw/ CFLAGS_bitfield_kunit.o := $(DISABLE_STRUCTLEAK_PLUGIN) obj-$(CONFIG_BITFIELD_KUNIT) += bitfield_kunit.o obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o +obj-$(CONFIG_HASHTABLE_KUNIT_TEST) += hashtable_test.o obj-$(CONFIG_LINEAR_RANGES_TEST) += test_linear_ranges.o obj-$(CONFIG_BITS_TEST) += test_bits.o obj-$(CONFIG_CMDLINE_KUNIT_TEST) += cmdline_kunit.o diff --git a/lib/hashtable_test.c b/lib/hashtable_test.c new file mode 100644 index 000000000000..7907df66a8e7 --- /dev/null +++ b/lib/hashtable_test.c @@ -0,0 +1,299 @@ +// SPDX-License-Identifier: GPL-2.0 +/*
- KUnit test for the Kernel Hashtable structures.
- Copyright (C) 2022, Google LLC.
- Author: Rae Moar rmoar@google.com
- */
+#include <kunit/test.h>
+#include <linux/hashtable.h>
+struct hashtable_test_entry {
int key;
int data;
struct hlist_node node;
int visited;
+};
+static void hashtable_test_hash_init(struct kunit *test) +{
/* Test the different ways of initialising a hashtable. */
DEFINE_HASHTABLE(hash1, 3);
DECLARE_HASHTABLE(hash2, 3);
hash_init(hash1);
hash_init(hash2);
KUNIT_EXPECT_TRUE(test, hash_empty(hash1));
KUNIT_EXPECT_TRUE(test, hash_empty(hash2));
+}
+static void hashtable_test_hash_empty(struct kunit *test) +{
struct hashtable_test_entry a;
DEFINE_HASHTABLE(hash, 3);
hash_init(hash);
KUNIT_EXPECT_TRUE(test, hash_empty(hash));
a.key = 1;
a.data = 13;
hash_add(hash, &a.node, a.key);
/* Hashtable should no longer be empty. */
KUNIT_EXPECT_FALSE(test, hash_empty(hash));
+}
+static void hashtable_test_hash_hashed(struct kunit *test) +{
struct hashtable_test_entry a, b;
DEFINE_HASHTABLE(hash, 3);
hash_init(hash);
a.key = 1;
a.data = 13;
b.key = 1;
b.data = 2;
hash_add(hash, &a.node, a.key);
hash_add(hash, &b.node, b.key);
KUNIT_EXPECT_TRUE(test, hash_hashed(&a.node));
KUNIT_EXPECT_TRUE(test, hash_hashed(&b.node));
+}
+static void hashtable_test_hash_add(struct kunit *test) +{
struct hashtable_test_entry a, b, *x;
int bkt;
DEFINE_HASHTABLE(hash, 3);
hash_init(hash);
a.key = 1;
a.data = 13;
a.visited = 0;
b.key = 2;
b.data = 10;
b.visited = 0;
hash_add(hash, &a.node, a.key);
hash_add(hash, &b.node, b.key);
hash_for_each(hash, bkt, x, node) {
if (x->key == a.key && x->data == a.data)
a.visited += 1;
if (x->key == b.key && x->data == b.data)
b.visited += 1;
}
x->visited += 1; or x->visited++; also do the same thing.
Oh right. That makes a lot of sense.
Note: given x is supposed to point to a or b, I don't know if checking against a.data does us much good. If we're trying to check that hash_add() doesn't mutate the keys and data, this code won't catch it. We'd have to instead do something like if(x->key != 1 && x->key != 2) KUNIT_FAIL(test, ...);
This seems like a good change to me in combination with changing it to x->visited++;. Although David's suggestion might be slightly more exhaustive. Why wouldn't it be important to check that the key matches the data?
/* Both entries should have been visited exactly once. */
KUNIT_EXPECT_EQ(test, a.visited, 1);
KUNIT_EXPECT_EQ(test, b.visited, 1);
+}
+static void hashtable_test_hash_del(struct kunit *test) +{
struct hashtable_test_entry a, b, *x;
DEFINE_HASHTABLE(hash, 3);
hash_init(hash);
a.key = 1;
a.data = 13;
b.key = 2;
b.data = 10;
b.visited = 0;
hash_add(hash, &a.node, a.key);
hash_add(hash, &b.node, b.key);
hash_del(&b.node);
hash_for_each_possible(hash, x, node, b.key) {
if (x->key == b.key && x->data == b.data)
b.visited += 1;
Similarly to above, x->visited += 1 (or ++) is probably better.
Right. Will switch this out here.
}
/* The deleted entry should not have been visited. */
KUNIT_EXPECT_EQ(test, b.visited, 0);
hash_del(&a.node);
/* The hashtable should be empty. */
KUNIT_EXPECT_TRUE(test, hash_empty(hash));
+}
+static void hashtable_test_hash_for_each(struct kunit *test) +{
struct hashtable_test_entry entries[3];
struct hashtable_test_entry *x;
int bkt, i, j, count;
DEFINE_HASHTABLE(hash, 3);
/* Initialize a hashtable with three entries. */
hash_init(hash);
for (i = 0; i < 3; i++) {
entries[i].key = i;
entries[i].data = i + 10;
entries[i].visited = 0;
hash_add(hash, &entries[i].node, entries[i].key);
}
count = 0;
hash_for_each(hash, bkt, x, node) {
if (x->key >= 0 && x->key < 3)
entries[x->key].visited += 1;
Would this be better using an assert to fail the test if we see unexpected keys? E.g. like if (x->key < 0 || x->key > 3) KUNIT_ASSERT_FAILURE(test, ...); x->visited++; count++; or KUNIT_ASSERT_GE(test, x->key, 0); KUNIT_ASSERT_LT(test, x->key, 3);
Yes, this makes a lot of sense. I will switch out just the if statements for using assert statements.
count++;
}
/* Should have visited each entry exactly once. */
KUNIT_EXPECT_EQ(test, count, 3);
for (j = 0; j < 3; j++)
KUNIT_EXPECT_EQ(test, entries[j].visited, 1);
+}
+static void hashtable_test_hash_for_each_safe(struct kunit *test) +{
struct hashtable_test_entry entries[3];
struct hashtable_test_entry *x;
struct hlist_node *tmp;
int bkt, i, j, count;
DEFINE_HASHTABLE(hash, 3);
/* Initialize a hashtable with three entries. */
hash_init(hash);
for (i = 0; i < 3; i++) {
entries[i].key = i;
entries[i].data = i + 10;
entries[i].visited = 0;
hash_add(hash, &entries[i].node, entries[i].key);
}
count = 0;
hash_for_each_safe(hash, bkt, tmp, x, node) {
if (x->key >= 0 && x->key < 3) {
entries[x->key].visited += 1;
hash_del(&entries[x->key].node);
}
count++;
}
/* Should have visited each entry exactly once. */
KUNIT_EXPECT_EQ(test, count, 3);
for (j = 0; j < 3; j++)
KUNIT_EXPECT_EQ(test, entries[j].visited, 1);
+}
+static void hashtable_test_hash_for_each_possible(struct kunit *test) +{
struct hashtable_test_entry entries[4];
struct hashtable_test_entry *x;
int i, j, count;
DEFINE_HASHTABLE(hash, 3);
/* Initialize a hashtable with three entries with key = 1. */
hash_init(hash);
for (i = 0; i < 3; i++) {
entries[i].key = 1;
entries[i].data = i;
entries[i].visited = 0;
hash_add(hash, &entries[i].node, entries[i].key);
}
/* Add an entry with key = 2. */
entries[3].key = 2;
entries[3].data = 3;
entries[3].visited = 0;
hash_add(hash, &entries[3].node, entries[3].key);
count = 0;
hash_for_each_possible(hash, x, node, 1) {
if (x->data >= 0 && x->data < 4)
entries[x->data].visited += 1;
count++;
}
/* Should have visited each entry with key = 1 exactly once. */
for (j = 0; j < 3; j++)
KUNIT_EXPECT_EQ(test, entries[j].visited, 1);
/* If entry with key = 2 is in the same bucket as the entries with
* key = 1, check it was visited. Otherwise ensure that only three
* entries were visited.
*/
if (hash_min(1, HASH_BITS(hash)) == hash_min(2, HASH_BITS(hash))) {
nit: this feels like we might be a bit too tied to the impl (not sure if it'll change anytime soon, but still).
Could we check the bucket using hash_for_each? E.g.
// assume we change the keys from {1,2} to {0,1} int buckets[2]; hash_for_each(hash, bkt, x, node) { buckets[x->key] = bkt; }
if (buckets[0] == buckets[1]) { // all in the same bucket ... } else { ... }
I really like the idea of using hash_for_each to determine the bucket. I will add this to the test.
KUNIT_EXPECT_EQ(test, count, 4);
KUNIT_EXPECT_EQ(test, entries[3].visited, 1);
} else {
KUNIT_EXPECT_EQ(test, count, 3);
should we also check that entries[3].visited == 0?
Right. Must have been a mistake on my end. Oops.
Daniel
Thanks Daniel! -Rae