Revision 9d514262425691dddf942edea8bc9919e66fe140 authored by Wanpeng Li on 13 May 2015, 06:01:03 UTC, committed by Ingo Molnar on 19 June 2015, 08:06:46 UTC
This patch adds a check that prevents futile attempts to move DL tasks to a CPU with active tasks of equal or earlier deadline. The same behavior as commit 80e3d87b2c55 ("sched/rt: Reduce rq lock contention by eliminating locking of non-feasible target") for rt class. Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1431496867-4194-3-git-send-email-wanpeng.li@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
1 parent a6c0e74
rbtree_test.c
#include <linux/module.h>
#include <linux/rbtree_augmented.h>
#include <linux/random.h>
#include <asm/timex.h>
#define NODES 100
#define PERF_LOOPS 100000
#define CHECK_LOOPS 100
struct test_node {
u32 key;
struct rb_node rb;
/* following fields used for testing augmented rbtree functionality */
u32 val;
u32 augmented;
};
static struct rb_root root = RB_ROOT;
static struct test_node nodes[NODES];
static struct rnd_state rnd;
static void insert(struct test_node *node, struct rb_root *root)
{
struct rb_node **new = &root->rb_node, *parent = NULL;
u32 key = node->key;
while (*new) {
parent = *new;
if (key < rb_entry(parent, struct test_node, rb)->key)
new = &parent->rb_left;
else
new = &parent->rb_right;
}
rb_link_node(&node->rb, parent, new);
rb_insert_color(&node->rb, root);
}
static inline void erase(struct test_node *node, struct rb_root *root)
{
rb_erase(&node->rb, root);
}
static inline u32 augment_recompute(struct test_node *node)
{
u32 max = node->val, child_augmented;
if (node->rb.rb_left) {
child_augmented = rb_entry(node->rb.rb_left, struct test_node,
rb)->augmented;
if (max < child_augmented)
max = child_augmented;
}
if (node->rb.rb_right) {
child_augmented = rb_entry(node->rb.rb_right, struct test_node,
rb)->augmented;
if (max < child_augmented)
max = child_augmented;
}
return max;
}
RB_DECLARE_CALLBACKS(static, augment_callbacks, struct test_node, rb,
u32, augmented, augment_recompute)
static void insert_augmented(struct test_node *node, struct rb_root *root)
{
struct rb_node **new = &root->rb_node, *rb_parent = NULL;
u32 key = node->key;
u32 val = node->val;
struct test_node *parent;
while (*new) {
rb_parent = *new;
parent = rb_entry(rb_parent, struct test_node, rb);
if (parent->augmented < val)
parent->augmented = val;
if (key < parent->key)
new = &parent->rb.rb_left;
else
new = &parent->rb.rb_right;
}
node->augmented = val;
rb_link_node(&node->rb, rb_parent, new);
rb_insert_augmented(&node->rb, root, &augment_callbacks);
}
static void erase_augmented(struct test_node *node, struct rb_root *root)
{
rb_erase_augmented(&node->rb, root, &augment_callbacks);
}
static void init(void)
{
int i;
for (i = 0; i < NODES; i++) {
nodes[i].key = prandom_u32_state(&rnd);
nodes[i].val = prandom_u32_state(&rnd);
}
}
static bool is_red(struct rb_node *rb)
{
return !(rb->__rb_parent_color & 1);
}
static int black_path_count(struct rb_node *rb)
{
int count;
for (count = 0; rb; rb = rb_parent(rb))
count += !is_red(rb);
return count;
}
static void check_postorder_foreach(int nr_nodes)
{
struct test_node *cur, *n;
int count = 0;
rbtree_postorder_for_each_entry_safe(cur, n, &root, rb)
count++;
WARN_ON_ONCE(count != nr_nodes);
}
static void check_postorder(int nr_nodes)
{
struct rb_node *rb;
int count = 0;
for (rb = rb_first_postorder(&root); rb; rb = rb_next_postorder(rb))
count++;
WARN_ON_ONCE(count != nr_nodes);
}
static void check(int nr_nodes)
{
struct rb_node *rb;
int count = 0, blacks = 0;
u32 prev_key = 0;
for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
struct test_node *node = rb_entry(rb, struct test_node, rb);
WARN_ON_ONCE(node->key < prev_key);
WARN_ON_ONCE(is_red(rb) &&
(!rb_parent(rb) || is_red(rb_parent(rb))));
if (!count)
blacks = black_path_count(rb);
else
WARN_ON_ONCE((!rb->rb_left || !rb->rb_right) &&
blacks != black_path_count(rb));
prev_key = node->key;
count++;
}
WARN_ON_ONCE(count != nr_nodes);
WARN_ON_ONCE(count < (1 << black_path_count(rb_last(&root))) - 1);
check_postorder(nr_nodes);
check_postorder_foreach(nr_nodes);
}
static void check_augmented(int nr_nodes)
{
struct rb_node *rb;
check(nr_nodes);
for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
struct test_node *node = rb_entry(rb, struct test_node, rb);
WARN_ON_ONCE(node->augmented != augment_recompute(node));
}
}
static int __init rbtree_test_init(void)
{
int i, j;
cycles_t time1, time2, time;
printk(KERN_ALERT "rbtree testing");
prandom_seed_state(&rnd, 3141592653589793238ULL);
init();
time1 = get_cycles();
for (i = 0; i < PERF_LOOPS; i++) {
for (j = 0; j < NODES; j++)
insert(nodes + j, &root);
for (j = 0; j < NODES; j++)
erase(nodes + j, &root);
}
time2 = get_cycles();
time = time2 - time1;
time = div_u64(time, PERF_LOOPS);
printk(" -> %llu cycles\n", (unsigned long long)time);
for (i = 0; i < CHECK_LOOPS; i++) {
init();
for (j = 0; j < NODES; j++) {
check(j);
insert(nodes + j, &root);
}
for (j = 0; j < NODES; j++) {
check(NODES - j);
erase(nodes + j, &root);
}
check(0);
}
printk(KERN_ALERT "augmented rbtree testing");
init();
time1 = get_cycles();
for (i = 0; i < PERF_LOOPS; i++) {
for (j = 0; j < NODES; j++)
insert_augmented(nodes + j, &root);
for (j = 0; j < NODES; j++)
erase_augmented(nodes + j, &root);
}
time2 = get_cycles();
time = time2 - time1;
time = div_u64(time, PERF_LOOPS);
printk(" -> %llu cycles\n", (unsigned long long)time);
for (i = 0; i < CHECK_LOOPS; i++) {
init();
for (j = 0; j < NODES; j++) {
check_augmented(j);
insert_augmented(nodes + j, &root);
}
for (j = 0; j < NODES; j++) {
check_augmented(NODES - j);
erase_augmented(nodes + j, &root);
}
check_augmented(0);
}
return -EAGAIN; /* Fail will directly unload the module */
}
static void __exit rbtree_test_exit(void)
{
printk(KERN_ALERT "test exit\n");
}
module_init(rbtree_test_init)
module_exit(rbtree_test_exit)
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Michel Lespinasse");
MODULE_DESCRIPTION("Red Black Tree test");
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