xemu/tests/test-qht.c
Emilio G. Cota 7266ae91a1 qht: do not segfault when gathering stats from an uninitialized qht
So far, QHT functions assume that the passed qht has previously been
initialized--otherwise they segfault.

This patch makes an exception for qht_statistics_init, with the goal
of simplifying calling code. For instance, qht_statistics_init is
called from the 'info jit' dump, and given that under KVM the TB qht
is never initialized, we get a segfault. Thus, instead of complicating
the 'info jit' code with additional checks, let's allow passing an
uninitialized qht to qht_statistics_init.

While at it, add a test for this to test-qht.

Before the patch (for $ qemu -enable-kvm [...]):
(qemu) info jit
[...]
direct jump count   0 (0%) (2 jumps=0 0%)
Program received signal SIGSEGV, Segmentation fault.

After the patch the "TB hash buckets", "TB hash occupancy"
and "TB hash avg chain" lines are omitted.
(qemu) info jit
[...]
direct jump count   0 (0%) (2 jumps=0 0%)
TB hash buckets     0/0 (-nan% head buckets used)
TB hash occupancy   nan% avg chain occ. Histogram: (null)
TB hash avg chain   nan buckets. Histogram: (null)
[...]

Reported by: Changlong Xie <xiecl.fnst@cn.fujitsu.com>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1469205390-14369-1-git-send-email-cota@braap.org>
[Extract printing statistics to an entirely separate function. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-08-02 12:03:58 +02:00

163 lines
3.0 KiB
C

/*
* Copyright (C) 2016, Emilio G. Cota <cota@braap.org>
*
* License: GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qemu/qht.h"
#define N 5000
static struct qht ht;
static int32_t arr[N * 2];
static bool is_equal(const void *obj, const void *userp)
{
const int32_t *a = obj;
const int32_t *b = userp;
return *a == *b;
}
static void insert(int a, int b)
{
int i;
for (i = a; i < b; i++) {
uint32_t hash;
arr[i] = i;
hash = i;
qht_insert(&ht, &arr[i], hash);
}
}
static void rm(int init, int end)
{
int i;
for (i = init; i < end; i++) {
uint32_t hash;
hash = arr[i];
g_assert_true(qht_remove(&ht, &arr[i], hash));
}
}
static void check(int a, int b, bool expected)
{
struct qht_stats stats;
int i;
for (i = a; i < b; i++) {
void *p;
uint32_t hash;
int32_t val;
val = i;
hash = i;
p = qht_lookup(&ht, is_equal, &val, hash);
g_assert_true(!!p == expected);
}
qht_statistics_init(&ht, &stats);
if (stats.used_head_buckets) {
g_assert_cmpfloat(qdist_avg(&stats.chain), >=, 1.0);
}
g_assert_cmpuint(stats.head_buckets, >, 0);
qht_statistics_destroy(&stats);
}
static void count_func(struct qht *ht, void *p, uint32_t hash, void *userp)
{
unsigned int *curr = userp;
(*curr)++;
}
static void check_n(size_t expected)
{
struct qht_stats stats;
qht_statistics_init(&ht, &stats);
g_assert_cmpuint(stats.entries, ==, expected);
qht_statistics_destroy(&stats);
}
static void iter_check(unsigned int count)
{
unsigned int curr = 0;
qht_iter(&ht, count_func, &curr);
g_assert_cmpuint(curr, ==, count);
}
static void qht_do_test(unsigned int mode, size_t init_entries)
{
/* under KVM we might fetch stats from an uninitialized qht */
check_n(0);
qht_init(&ht, 0, mode);
check_n(0);
insert(0, N);
check(0, N, true);
check_n(N);
check(-N, -1, false);
iter_check(N);
rm(101, 102);
check_n(N - 1);
insert(N, N * 2);
check_n(N + N - 1);
rm(N, N * 2);
check_n(N - 1);
insert(101, 102);
check_n(N);
rm(10, 200);
check_n(N - 190);
insert(150, 200);
check_n(N - 190 + 50);
insert(10, 150);
check_n(N);
rm(1, 2);
check_n(N - 1);
qht_reset_size(&ht, 0);
check_n(0);
check(0, N, false);
qht_destroy(&ht);
}
static void qht_test(unsigned int mode)
{
qht_do_test(mode, 0);
qht_do_test(mode, 1);
qht_do_test(mode, 2);
qht_do_test(mode, 8);
qht_do_test(mode, 16);
qht_do_test(mode, 8192);
qht_do_test(mode, 16384);
}
static void test_default(void)
{
qht_test(0);
}
static void test_resize(void)
{
qht_test(QHT_MODE_AUTO_RESIZE);
}
int main(int argc, char *argv[])
{
g_test_init(&argc, &argv, NULL);
g_test_add_func("/qht/mode/default", test_default);
g_test_add_func("/qht/mode/resize", test_resize);
return g_test_run();
}