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linux-stable/kernel/sched/debug.c
Huang Ying 33024536ba memory tiering: hot page selection with hint page fault latency 
Patch series "memory tiering: hot page selection", v4.

To optimize page placement in a memory tiering system with NUMA balancing,
the hot pages in the slow memory nodes need to be identified. 
Essentially, the original NUMA balancing implementation selects the mostly
recently accessed (MRU) pages to promote.  But this isn't a perfect
algorithm to identify the hot pages.  Because the pages with quite low
access frequency may be accessed eventually given the NUMA balancing page
table scanning period could be quite long (e.g.  60 seconds).  So in this
patchset, we implement a new hot page identification algorithm based on
the latency between NUMA balancing page table scanning and hint page
fault.  Which is a kind of mostly frequently accessed (MFU) algorithm.

In NUMA balancing memory tiering mode, if there are hot pages in slow
memory node and cold pages in fast memory node, we need to promote/demote
hot/cold pages between the fast and cold memory nodes.

A choice is to promote/demote as fast as possible.  But the CPU cycles and
memory bandwidth consumed by the high promoting/demoting throughput will
hurt the latency of some workload because of accessing inflating and slow
memory bandwidth contention.

A way to resolve this issue is to restrict the max promoting/demoting
throughput.  It will take longer to finish the promoting/demoting.  But
the workload latency will be better.  This is implemented in this patchset
as the page promotion rate limit mechanism.

The promotion hot threshold is workload and system configuration
dependent.  So in this patchset, a method to adjust the hot threshold
automatically is implemented.  The basic idea is to control the number of
the candidate promotion pages to match the promotion rate limit.

We used the pmbench memory accessing benchmark tested the patchset on a
2-socket server system with DRAM and PMEM installed.  The test results are
as follows,

		pmbench score		promote rate
		 (accesses/s)			MB/s
		-------------		------------
base		  146887704.1		       725.6
hot selection     165695601.2		       544.0
rate limit	  162814569.8		       165.2
auto adjustment	  170495294.0                  136.9

From the results above,

With hot page selection patch [1/3], the pmbench score increases about
12.8%, and promote rate (overhead) decreases about 25.0%, compared with
base kernel.

With rate limit patch [2/3], pmbench score decreases about 1.7%, and
promote rate decreases about 69.6%, compared with hot page selection
patch.

With threshold auto adjustment patch [3/3], pmbench score increases about
4.7%, and promote rate decrease about 17.1%, compared with rate limit
patch.

Baolin helped to test the patchset with MySQL on a machine which contains
1 DRAM node (30G) and 1 PMEM node (126G).

sysbench /usr/share/sysbench/oltp_read_write.lua \
......
--tables=200 \
--table-size=1000000 \
--report-interval=10 \
--threads=16 \
--time=120

The tps can be improved about 5%.


This patch (of 3):

To optimize page placement in a memory tiering system with NUMA balancing,
the hot pages in the slow memory node need to be identified.  Essentially,
the original NUMA balancing implementation selects the mostly recently
accessed (MRU) pages to promote.  But this isn't a perfect algorithm to
identify the hot pages.  Because the pages with quite low access frequency
may be accessed eventually given the NUMA balancing page table scanning
period could be quite long (e.g.  60 seconds).  The most frequently
accessed (MFU) algorithm is better.

So, in this patch we implemented a better hot page selection algorithm. 
Which is based on NUMA balancing page table scanning and hint page fault
as follows,

- When the page tables of the processes are scanned to change PTE/PMD
  to be PROT_NONE, the current time is recorded in struct page as scan
  time.

- When the page is accessed, hint page fault will occur.  The scan
  time is gotten from the struct page.  And The hint page fault
  latency is defined as

    hint page fault time - scan time

The shorter the hint page fault latency of a page is, the higher the
probability of their access frequency to be higher.  So the hint page
fault latency is a better estimation of the page hot/cold.

It's hard to find some extra space in struct page to hold the scan time. 
Fortunately, we can reuse some bits used by the original NUMA balancing.

NUMA balancing uses some bits in struct page to store the page accessing
CPU and PID (referring to page_cpupid_xchg_last()).  Which is used by the
multi-stage node selection algorithm to avoid to migrate pages shared
accessed by the NUMA nodes back and forth.  But for pages in the slow
memory node, even if they are shared accessed by multiple NUMA nodes, as
long as the pages are hot, they need to be promoted to the fast memory
node.  So the accessing CPU and PID information are unnecessary for the
slow memory pages.  We can reuse these bits in struct page to record the
scan time.  For the fast memory pages, these bits are used as before.

For the hot threshold, the default value is 1 second, which works well in
our performance test.  All pages with hint page fault latency < hot
threshold will be considered hot.

It's hard for users to determine the hot threshold.  So we don't provide a
kernel ABI to set it, just provide a debugfs interface for advanced users
to experiment.  We will continue to work on a hot threshold automatic
adjustment mechanism.

The downside of the above method is that the response time to the workload
hot spot changing may be much longer.  For example,

- A previous cold memory area becomes hot

- The hint page fault will be triggered.  But the hint page fault
  latency isn't shorter than the hot threshold.  So the pages will
  not be promoted.

- When the memory area is scanned again, maybe after a scan period,
  the hint page fault latency measured will be shorter than the hot
  threshold and the pages will be promoted.

To mitigate this, if there are enough free space in the fast memory node,
the hot threshold will not be used, all pages will be promoted upon the
hint page fault for fast response.

Thanks Zhong Jiang reported and tested the fix for a bug when disabling
memory tiering mode dynamically.

Link: https://lkml.kernel.org/r/20220713083954.34196-1-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20220713083954.34196-2-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Wei Xu <weixugc@google.com>
Cc: osalvador <osalvador@suse.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Zhong Jiang <zhongjiang-ali@linux.alibaba.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-11 20:25:54 -07:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* kernel/sched/debug.c
*
* Print the CFS rbtree and other debugging details
*
* Copyright(C) 2007, Red Hat, Inc., Ingo Molnar
*/
/*
* This allows printing both to /proc/sched_debug and
* to the console
*/
#define SEQ_printf(m, x...) \
do { \
if (m) \
seq_printf(m, x); \
else \
pr_cont(x); \
} while (0)
/*
* Ease the printing of nsec fields:
*/
static long long nsec_high(unsigned long long nsec)
{
if ((long long)nsec < 0) {
nsec = -nsec;
do_div(nsec, 1000000);
return -nsec;
}
do_div(nsec, 1000000);
return nsec;
}
static unsigned long nsec_low(unsigned long long nsec)
{
if ((long long)nsec < 0)
nsec = -nsec;
return do_div(nsec, 1000000);
}
#define SPLIT_NS(x) nsec_high(x), nsec_low(x)
#define SCHED_FEAT(name, enabled) \
#name ,
static const char * const sched_feat_names[] = {
#include "features.h"
};
#undef SCHED_FEAT
static int sched_feat_show(struct seq_file *m, void *v)
{
int i;
for (i = 0; i < __SCHED_FEAT_NR; i++) {
if (!(sysctl_sched_features & (1UL << i)))
seq_puts(m, "NO_");
seq_printf(m, "%s ", sched_feat_names[i]);
}
seq_puts(m, "\n");
return 0;
}
#ifdef CONFIG_JUMP_LABEL
#define jump_label_key__true STATIC_KEY_INIT_TRUE
#define jump_label_key__false STATIC_KEY_INIT_FALSE
#define SCHED_FEAT(name, enabled) \
jump_label_key__##enabled ,
struct static_key sched_feat_keys[__SCHED_FEAT_NR] = {
#include "features.h"
};
#undef SCHED_FEAT
static void sched_feat_disable(int i)
{
static_key_disable_cpuslocked(&sched_feat_keys[i]);
}
static void sched_feat_enable(int i)
{
static_key_enable_cpuslocked(&sched_feat_keys[i]);
}
#else
static void sched_feat_disable(int i) { };
static void sched_feat_enable(int i) { };
#endif /* CONFIG_JUMP_LABEL */
static int sched_feat_set(char *cmp)
{
int i;
int neg = 0;
if (strncmp(cmp, "NO_", 3) == 0) {
neg = 1;
cmp += 3;
}
i = match_string(sched_feat_names, __SCHED_FEAT_NR, cmp);
if (i < 0)
return i;
if (neg) {
sysctl_sched_features &= ~(1UL << i);
sched_feat_disable(i);
} else {
sysctl_sched_features |= (1UL << i);
sched_feat_enable(i);
}
return 0;
}
static ssize_t
sched_feat_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char buf[64];
char *cmp;
int ret;
struct inode *inode;
if (cnt > 63)
cnt = 63;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
buf[cnt] = 0;
cmp = strstrip(buf);
/* Ensure the static_key remains in a consistent state */
inode = file_inode(filp);
cpus_read_lock();
inode_lock(inode);
ret = sched_feat_set(cmp);
inode_unlock(inode);
cpus_read_unlock();
if (ret < 0)
return ret;
*ppos += cnt;
return cnt;
}
static int sched_feat_open(struct inode *inode, struct file *filp)
{
return single_open(filp, sched_feat_show, NULL);
}
static const struct file_operations sched_feat_fops = {
.open = sched_feat_open,
.write = sched_feat_write,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
#ifdef CONFIG_SMP
static ssize_t sched_scaling_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char buf[16];
unsigned int scaling;
if (cnt > 15)
cnt = 15;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
buf[cnt] = '\0';
if (kstrtouint(buf, 10, &scaling))
return -EINVAL;
if (scaling >= SCHED_TUNABLESCALING_END)
return -EINVAL;
sysctl_sched_tunable_scaling = scaling;
if (sched_update_scaling())
return -EINVAL;
*ppos += cnt;
return cnt;
}
static int sched_scaling_show(struct seq_file *m, void *v)
{
seq_printf(m, "%d\n", sysctl_sched_tunable_scaling);
return 0;
}
static int sched_scaling_open(struct inode *inode, struct file *filp)
{
return single_open(filp, sched_scaling_show, NULL);
}
static const struct file_operations sched_scaling_fops = {
.open = sched_scaling_open,
.write = sched_scaling_write,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
#endif /* SMP */
#ifdef CONFIG_PREEMPT_DYNAMIC
static ssize_t sched_dynamic_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char buf[16];
int mode;
if (cnt > 15)
cnt = 15;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
buf[cnt] = 0;
mode = sched_dynamic_mode(strstrip(buf));
if (mode < 0)
return mode;
sched_dynamic_update(mode);
*ppos += cnt;
return cnt;
}
static int sched_dynamic_show(struct seq_file *m, void *v)
{
static const char * preempt_modes[] = {
"none", "voluntary", "full"
};
int i;
for (i = 0; i < ARRAY_SIZE(preempt_modes); i++) {
if (preempt_dynamic_mode == i)
seq_puts(m, "(");
seq_puts(m, preempt_modes[i]);
if (preempt_dynamic_mode == i)
seq_puts(m, ")");
seq_puts(m, " ");
}
seq_puts(m, "\n");
return 0;
}
static int sched_dynamic_open(struct inode *inode, struct file *filp)
{
return single_open(filp, sched_dynamic_show, NULL);
}
static const struct file_operations sched_dynamic_fops = {
.open = sched_dynamic_open,
.write = sched_dynamic_write,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
#endif /* CONFIG_PREEMPT_DYNAMIC */
__read_mostly bool sched_debug_verbose;
static const struct seq_operations sched_debug_sops;
static int sched_debug_open(struct inode *inode, struct file *filp)
{
return seq_open(filp, &sched_debug_sops);
}
static const struct file_operations sched_debug_fops = {
.open = sched_debug_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static struct dentry *debugfs_sched;
static __init int sched_init_debug(void)
{
struct dentry __maybe_unused *numa;
debugfs_sched = debugfs_create_dir("sched", NULL);
debugfs_create_file("features", 0644, debugfs_sched, NULL, &sched_feat_fops);
debugfs_create_bool("verbose", 0644, debugfs_sched, &sched_debug_verbose);
#ifdef CONFIG_PREEMPT_DYNAMIC
debugfs_create_file("preempt", 0644, debugfs_sched, NULL, &sched_dynamic_fops);
#endif
debugfs_create_u32("latency_ns", 0644, debugfs_sched, &sysctl_sched_latency);
debugfs_create_u32("min_granularity_ns", 0644, debugfs_sched, &sysctl_sched_min_granularity);
debugfs_create_u32("idle_min_granularity_ns", 0644, debugfs_sched, &sysctl_sched_idle_min_granularity);
debugfs_create_u32("wakeup_granularity_ns", 0644, debugfs_sched, &sysctl_sched_wakeup_granularity);
debugfs_create_u32("latency_warn_ms", 0644, debugfs_sched, &sysctl_resched_latency_warn_ms);
debugfs_create_u32("latency_warn_once", 0644, debugfs_sched, &sysctl_resched_latency_warn_once);
#ifdef CONFIG_SMP
debugfs_create_file("tunable_scaling", 0644, debugfs_sched, NULL, &sched_scaling_fops);
debugfs_create_u32("migration_cost_ns", 0644, debugfs_sched, &sysctl_sched_migration_cost);
debugfs_create_u32("nr_migrate", 0644, debugfs_sched, &sysctl_sched_nr_migrate);
mutex_lock(&sched_domains_mutex);
update_sched_domain_debugfs();
mutex_unlock(&sched_domains_mutex);
#endif
#ifdef CONFIG_NUMA_BALANCING
numa = debugfs_create_dir("numa_balancing", debugfs_sched);
debugfs_create_u32("scan_delay_ms", 0644, numa, &sysctl_numa_balancing_scan_delay);
debugfs_create_u32("scan_period_min_ms", 0644, numa, &sysctl_numa_balancing_scan_period_min);
debugfs_create_u32("scan_period_max_ms", 0644, numa, &sysctl_numa_balancing_scan_period_max);
debugfs_create_u32("scan_size_mb", 0644, numa, &sysctl_numa_balancing_scan_size);
debugfs_create_u32("hot_threshold_ms", 0644, numa, &sysctl_numa_balancing_hot_threshold);
#endif
debugfs_create_file("debug", 0444, debugfs_sched, NULL, &sched_debug_fops);
return 0;
}
late_initcall(sched_init_debug);
#ifdef CONFIG_SMP
static cpumask_var_t sd_sysctl_cpus;
static struct dentry *sd_dentry;
static int sd_flags_show(struct seq_file *m, void *v)
{
unsigned long flags = *(unsigned int *)m->private;
int idx;
for_each_set_bit(idx, &flags, __SD_FLAG_CNT) {
seq_puts(m, sd_flag_debug[idx].name);
seq_puts(m, " ");
}
seq_puts(m, "\n");
return 0;
}
static int sd_flags_open(struct inode *inode, struct file *file)
{
return single_open(file, sd_flags_show, inode->i_private);
}
static const struct file_operations sd_flags_fops = {
.open = sd_flags_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static void register_sd(struct sched_domain *sd, struct dentry *parent)
{
#define SDM(type, mode, member) \
debugfs_create_##type(#member, mode, parent, &sd->member)
SDM(ulong, 0644, min_interval);
SDM(ulong, 0644, max_interval);
SDM(u64, 0644, max_newidle_lb_cost);
SDM(u32, 0644, busy_factor);
SDM(u32, 0644, imbalance_pct);
SDM(u32, 0644, cache_nice_tries);
SDM(str, 0444, name);
#undef SDM
debugfs_create_file("flags", 0444, parent, &sd->flags, &sd_flags_fops);
}
void update_sched_domain_debugfs(void)
{
int cpu, i;
/*
* This can unfortunately be invoked before sched_debug_init() creates
* the debug directory. Don't touch sd_sysctl_cpus until then.
*/
if (!debugfs_sched)
return;
if (!cpumask_available(sd_sysctl_cpus)) {
if (!alloc_cpumask_var(&sd_sysctl_cpus, GFP_KERNEL))
return;
cpumask_copy(sd_sysctl_cpus, cpu_possible_mask);
}
if (!sd_dentry)
sd_dentry = debugfs_create_dir("domains", debugfs_sched);
for_each_cpu(cpu, sd_sysctl_cpus) {
struct sched_domain *sd;
struct dentry *d_cpu;
char buf[32];
snprintf(buf, sizeof(buf), "cpu%d", cpu);
debugfs_remove(debugfs_lookup(buf, sd_dentry));
d_cpu = debugfs_create_dir(buf, sd_dentry);
i = 0;
for_each_domain(cpu, sd) {
struct dentry *d_sd;
snprintf(buf, sizeof(buf), "domain%d", i);
d_sd = debugfs_create_dir(buf, d_cpu);
register_sd(sd, d_sd);
i++;
}
__cpumask_clear_cpu(cpu, sd_sysctl_cpus);
}
}
void dirty_sched_domain_sysctl(int cpu)
{
if (cpumask_available(sd_sysctl_cpus))
__cpumask_set_cpu(cpu, sd_sysctl_cpus);
}
#endif /* CONFIG_SMP */
#ifdef CONFIG_FAIR_GROUP_SCHED
static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group *tg)
{
struct sched_entity *se = tg->se[cpu];
#define P(F) SEQ_printf(m, " .%-30s: %lld\n", #F, (long long)F)
#define P_SCHEDSTAT(F) SEQ_printf(m, " .%-30s: %lld\n", \
#F, (long long)schedstat_val(stats->F))
#define PN(F) SEQ_printf(m, " .%-30s: %lld.%06ld\n", #F, SPLIT_NS((long long)F))
#define PN_SCHEDSTAT(F) SEQ_printf(m, " .%-30s: %lld.%06ld\n", \
#F, SPLIT_NS((long long)schedstat_val(stats->F)))
if (!se)
return;
PN(se->exec_start);
PN(se->vruntime);
PN(se->sum_exec_runtime);
if (schedstat_enabled()) {
struct sched_statistics *stats;
stats = __schedstats_from_se(se);
PN_SCHEDSTAT(wait_start);
PN_SCHEDSTAT(sleep_start);
PN_SCHEDSTAT(block_start);
PN_SCHEDSTAT(sleep_max);
PN_SCHEDSTAT(block_max);
PN_SCHEDSTAT(exec_max);
PN_SCHEDSTAT(slice_max);
PN_SCHEDSTAT(wait_max);
PN_SCHEDSTAT(wait_sum);
P_SCHEDSTAT(wait_count);
}
P(se->load.weight);
#ifdef CONFIG_SMP
P(se->avg.load_avg);
P(se->avg.util_avg);
P(se->avg.runnable_avg);
#endif
#undef PN_SCHEDSTAT
#undef PN
#undef P_SCHEDSTAT
#undef P
}
#endif
#ifdef CONFIG_CGROUP_SCHED
static DEFINE_SPINLOCK(sched_debug_lock);
static char group_path[PATH_MAX];
static void task_group_path(struct task_group *tg, char *path, int plen)
{
if (autogroup_path(tg, path, plen))
return;
cgroup_path(tg->css.cgroup, path, plen);
}
/*
* Only 1 SEQ_printf_task_group_path() caller can use the full length
* group_path[] for cgroup path. Other simultaneous callers will have
* to use a shorter stack buffer. A "..." suffix is appended at the end
* of the stack buffer so that it will show up in case the output length
* matches the given buffer size to indicate possible path name truncation.
*/
#define SEQ_printf_task_group_path(m, tg, fmt...) \
{ \
if (spin_trylock(&sched_debug_lock)) { \
task_group_path(tg, group_path, sizeof(group_path)); \
SEQ_printf(m, fmt, group_path); \
spin_unlock(&sched_debug_lock); \
} else { \
char buf[128]; \
char *bufend = buf + sizeof(buf) - 3; \
task_group_path(tg, buf, bufend - buf); \
strcpy(bufend - 1, "..."); \
SEQ_printf(m, fmt, buf); \
} \
}
#endif
static void
print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
{
if (task_current(rq, p))
SEQ_printf(m, ">R");
else
SEQ_printf(m, " %c", task_state_to_char(p));
SEQ_printf(m, " %15s %5d %9Ld.%06ld %9Ld %5d ",
p->comm, task_pid_nr(p),
SPLIT_NS(p->se.vruntime),
(long long)(p->nvcsw + p->nivcsw),
p->prio);
SEQ_printf(m, "%9lld.%06ld %9lld.%06ld %9lld.%06ld %9lld.%06ld",
SPLIT_NS(schedstat_val_or_zero(p->stats.wait_sum)),
SPLIT_NS(p->se.sum_exec_runtime),
SPLIT_NS(schedstat_val_or_zero(p->stats.sum_sleep_runtime)),
SPLIT_NS(schedstat_val_or_zero(p->stats.sum_block_runtime)));
#ifdef CONFIG_NUMA_BALANCING
SEQ_printf(m, " %d %d", task_node(p), task_numa_group_id(p));
#endif
#ifdef CONFIG_CGROUP_SCHED
SEQ_printf_task_group_path(m, task_group(p), " %s")
#endif
SEQ_printf(m, "\n");
}
static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu)
{
struct task_struct *g, *p;
SEQ_printf(m, "\n");
SEQ_printf(m, "runnable tasks:\n");
SEQ_printf(m, " S task PID tree-key switches prio"
" wait-time sum-exec sum-sleep\n");
SEQ_printf(m, "-------------------------------------------------------"
"------------------------------------------------------\n");
rcu_read_lock();
for_each_process_thread(g, p) {
if (task_cpu(p) != rq_cpu)
continue;
print_task(m, rq, p);
}
rcu_read_unlock();
}
void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
{
s64 MIN_vruntime = -1, min_vruntime, max_vruntime = -1,
spread, rq0_min_vruntime, spread0;
struct rq *rq = cpu_rq(cpu);
struct sched_entity *last;
unsigned long flags;
#ifdef CONFIG_FAIR_GROUP_SCHED
SEQ_printf(m, "\n");
SEQ_printf_task_group_path(m, cfs_rq->tg, "cfs_rq[%d]:%s\n", cpu);
#else
SEQ_printf(m, "\n");
SEQ_printf(m, "cfs_rq[%d]:\n", cpu);
#endif
SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "exec_clock",
SPLIT_NS(cfs_rq->exec_clock));
raw_spin_rq_lock_irqsave(rq, flags);
if (rb_first_cached(&cfs_rq->tasks_timeline))
MIN_vruntime = (__pick_first_entity(cfs_rq))->vruntime;
last = __pick_last_entity(cfs_rq);
if (last)
max_vruntime = last->vruntime;
min_vruntime = cfs_rq->min_vruntime;
rq0_min_vruntime = cpu_rq(0)->cfs.min_vruntime;
raw_spin_rq_unlock_irqrestore(rq, flags);
SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "MIN_vruntime",
SPLIT_NS(MIN_vruntime));
SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "min_vruntime",
SPLIT_NS(min_vruntime));
SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "max_vruntime",
SPLIT_NS(max_vruntime));
spread = max_vruntime - MIN_vruntime;
SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "spread",
SPLIT_NS(spread));
spread0 = min_vruntime - rq0_min_vruntime;
SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "spread0",
SPLIT_NS(spread0));
SEQ_printf(m, " .%-30s: %d\n", "nr_spread_over",
cfs_rq->nr_spread_over);
SEQ_printf(m, " .%-30s: %d\n", "nr_running", cfs_rq->nr_running);
SEQ_printf(m, " .%-30s: %d\n", "h_nr_running", cfs_rq->h_nr_running);
SEQ_printf(m, " .%-30s: %d\n", "idle_nr_running",
cfs_rq->idle_nr_running);
SEQ_printf(m, " .%-30s: %d\n", "idle_h_nr_running",
cfs_rq->idle_h_nr_running);
SEQ_printf(m, " .%-30s: %ld\n", "load", cfs_rq->load.weight);
#ifdef CONFIG_SMP
SEQ_printf(m, " .%-30s: %lu\n", "load_avg",
cfs_rq->avg.load_avg);
SEQ_printf(m, " .%-30s: %lu\n", "runnable_avg",
cfs_rq->avg.runnable_avg);
SEQ_printf(m, " .%-30s: %lu\n", "util_avg",
cfs_rq->avg.util_avg);
SEQ_printf(m, " .%-30s: %u\n", "util_est_enqueued",
cfs_rq->avg.util_est.enqueued);
SEQ_printf(m, " .%-30s: %ld\n", "removed.load_avg",
cfs_rq->removed.load_avg);
SEQ_printf(m, " .%-30s: %ld\n", "removed.util_avg",
cfs_rq->removed.util_avg);
SEQ_printf(m, " .%-30s: %ld\n", "removed.runnable_avg",
cfs_rq->removed.runnable_avg);
#ifdef CONFIG_FAIR_GROUP_SCHED
SEQ_printf(m, " .%-30s: %lu\n", "tg_load_avg_contrib",
cfs_rq->tg_load_avg_contrib);
SEQ_printf(m, " .%-30s: %ld\n", "tg_load_avg",
atomic_long_read(&cfs_rq->tg->load_avg));
#endif
#endif
#ifdef CONFIG_CFS_BANDWIDTH
SEQ_printf(m, " .%-30s: %d\n", "throttled",
cfs_rq->throttled);
SEQ_printf(m, " .%-30s: %d\n", "throttle_count",
cfs_rq->throttle_count);
#endif
#ifdef CONFIG_FAIR_GROUP_SCHED
print_cfs_group_stats(m, cpu, cfs_rq->tg);
#endif
}
void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq)
{
#ifdef CONFIG_RT_GROUP_SCHED
SEQ_printf(m, "\n");
SEQ_printf_task_group_path(m, rt_rq->tg, "rt_rq[%d]:%s\n", cpu);
#else
SEQ_printf(m, "\n");
SEQ_printf(m, "rt_rq[%d]:\n", cpu);
#endif
#define P(x) \
SEQ_printf(m, " .%-30s: %Ld\n", #x, (long long)(rt_rq->x))
#define PU(x) \
SEQ_printf(m, " .%-30s: %lu\n", #x, (unsigned long)(rt_rq->x))
#define PN(x) \
SEQ_printf(m, " .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rt_rq->x))
PU(rt_nr_running);
#ifdef CONFIG_SMP
PU(rt_nr_migratory);
#endif
P(rt_throttled);
PN(rt_time);
PN(rt_runtime);
#undef PN
#undef PU
#undef P
}
void print_dl_rq(struct seq_file *m, int cpu, struct dl_rq *dl_rq)
{
struct dl_bw *dl_bw;
SEQ_printf(m, "\n");
SEQ_printf(m, "dl_rq[%d]:\n", cpu);
#define PU(x) \
SEQ_printf(m, " .%-30s: %lu\n", #x, (unsigned long)(dl_rq->x))
PU(dl_nr_running);
#ifdef CONFIG_SMP
PU(dl_nr_migratory);
dl_bw = &cpu_rq(cpu)->rd->dl_bw;
#else
dl_bw = &dl_rq->dl_bw;
#endif
SEQ_printf(m, " .%-30s: %lld\n", "dl_bw->bw", dl_bw->bw);
SEQ_printf(m, " .%-30s: %lld\n", "dl_bw->total_bw", dl_bw->total_bw);
#undef PU
}
static void print_cpu(struct seq_file *m, int cpu)
{
struct rq *rq = cpu_rq(cpu);
#ifdef CONFIG_X86
{
unsigned int freq = cpu_khz ? : 1;
SEQ_printf(m, "cpu#%d, %u.%03u MHz\n",
cpu, freq / 1000, (freq % 1000));
}
#else
SEQ_printf(m, "cpu#%d\n", cpu);
#endif
#define P(x) \
do { \
if (sizeof(rq->x) == 4) \
SEQ_printf(m, " .%-30s: %ld\n", #x, (long)(rq->x)); \
else \
SEQ_printf(m, " .%-30s: %Ld\n", #x, (long long)(rq->x));\
} while (0)
#define PN(x) \
SEQ_printf(m, " .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rq->x))
P(nr_running);
P(nr_switches);
P(nr_uninterruptible);
PN(next_balance);
SEQ_printf(m, " .%-30s: %ld\n", "curr->pid", (long)(task_pid_nr(rq->curr)));
PN(clock);
PN(clock_task);
#undef P
#undef PN
#ifdef CONFIG_SMP
#define P64(n) SEQ_printf(m, " .%-30s: %Ld\n", #n, rq->n);
P64(avg_idle);
P64(max_idle_balance_cost);
#undef P64
#endif
#define P(n) SEQ_printf(m, " .%-30s: %d\n", #n, schedstat_val(rq->n));
if (schedstat_enabled()) {
P(yld_count);
P(sched_count);
P(sched_goidle);
P(ttwu_count);
P(ttwu_local);
}
#undef P
print_cfs_stats(m, cpu);
print_rt_stats(m, cpu);
print_dl_stats(m, cpu);
print_rq(m, rq, cpu);
SEQ_printf(m, "\n");
}
static const char *sched_tunable_scaling_names[] = {
"none",
"logarithmic",
"linear"
};
static void sched_debug_header(struct seq_file *m)
{
u64 ktime, sched_clk, cpu_clk;
unsigned long flags;
local_irq_save(flags);
ktime = ktime_to_ns(ktime_get());
sched_clk = sched_clock();
cpu_clk = local_clock();
local_irq_restore(flags);
SEQ_printf(m, "Sched Debug Version: v0.11, %s %.*s\n",
init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version);
#define P(x) \
SEQ_printf(m, "%-40s: %Ld\n", #x, (long long)(x))
#define PN(x) \
SEQ_printf(m, "%-40s: %Ld.%06ld\n", #x, SPLIT_NS(x))
PN(ktime);
PN(sched_clk);
PN(cpu_clk);
P(jiffies);
#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
P(sched_clock_stable());
#endif
#undef PN
#undef P
SEQ_printf(m, "\n");
SEQ_printf(m, "sysctl_sched\n");
#define P(x) \
SEQ_printf(m, " .%-40s: %Ld\n", #x, (long long)(x))
#define PN(x) \
SEQ_printf(m, " .%-40s: %Ld.%06ld\n", #x, SPLIT_NS(x))
PN(sysctl_sched_latency);
PN(sysctl_sched_min_granularity);
PN(sysctl_sched_idle_min_granularity);
PN(sysctl_sched_wakeup_granularity);
P(sysctl_sched_child_runs_first);
P(sysctl_sched_features);
#undef PN
#undef P
SEQ_printf(m, " .%-40s: %d (%s)\n",
"sysctl_sched_tunable_scaling",
sysctl_sched_tunable_scaling,
sched_tunable_scaling_names[sysctl_sched_tunable_scaling]);
SEQ_printf(m, "\n");
}
static int sched_debug_show(struct seq_file *m, void *v)
{
int cpu = (unsigned long)(v - 2);
if (cpu != -1)
print_cpu(m, cpu);
else
sched_debug_header(m);
return 0;
}
void sysrq_sched_debug_show(void)
{
int cpu;
sched_debug_header(NULL);
for_each_online_cpu(cpu) {
/*
* Need to reset softlockup watchdogs on all CPUs, because
* another CPU might be blocked waiting for us to process
* an IPI or stop_machine.
*/
touch_nmi_watchdog();
touch_all_softlockup_watchdogs();
print_cpu(NULL, cpu);
}
}
/*
* This iterator needs some explanation.
* It returns 1 for the header position.
* This means 2 is CPU 0.
* In a hotplugged system some CPUs, including CPU 0, may be missing so we have
* to use cpumask_* to iterate over the CPUs.
*/
static void *sched_debug_start(struct seq_file *file, loff_t *offset)
{
unsigned long n = *offset;
if (n == 0)
return (void *) 1;
n--;
if (n > 0)
n = cpumask_next(n - 1, cpu_online_mask);
else
n = cpumask_first(cpu_online_mask);
*offset = n + 1;
if (n < nr_cpu_ids)
return (void *)(unsigned long)(n + 2);
return NULL;
}
static void *sched_debug_next(struct seq_file *file, void *data, loff_t *offset)
{
(*offset)++;
return sched_debug_start(file, offset);
}
static void sched_debug_stop(struct seq_file *file, void *data)
{
}
static const struct seq_operations sched_debug_sops = {
.start = sched_debug_start,
.next = sched_debug_next,
.stop = sched_debug_stop,
.show = sched_debug_show,
};
#define __PS(S, F) SEQ_printf(m, "%-45s:%21Ld\n", S, (long long)(F))
#define __P(F) __PS(#F, F)
#define P(F) __PS(#F, p->F)
#define PM(F, M) __PS(#F, p->F & (M))
#define __PSN(S, F) SEQ_printf(m, "%-45s:%14Ld.%06ld\n", S, SPLIT_NS((long long)(F)))
#define __PN(F) __PSN(#F, F)
#define PN(F) __PSN(#F, p->F)
#ifdef CONFIG_NUMA_BALANCING
void print_numa_stats(struct seq_file *m, int node, unsigned long tsf,
unsigned long tpf, unsigned long gsf, unsigned long gpf)
{
SEQ_printf(m, "numa_faults node=%d ", node);
SEQ_printf(m, "task_private=%lu task_shared=%lu ", tpf, tsf);
SEQ_printf(m, "group_private=%lu group_shared=%lu\n", gpf, gsf);
}
#endif
static void sched_show_numa(struct task_struct *p, struct seq_file *m)
{
#ifdef CONFIG_NUMA_BALANCING
if (p->mm)
P(mm->numa_scan_seq);
P(numa_pages_migrated);
P(numa_preferred_nid);
P(total_numa_faults);
SEQ_printf(m, "current_node=%d, numa_group_id=%d\n",
task_node(p), task_numa_group_id(p));
show_numa_stats(p, m);
#endif
}
void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
struct seq_file *m)
{
unsigned long nr_switches;
SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, task_pid_nr_ns(p, ns),
get_nr_threads(p));
SEQ_printf(m,
"---------------------------------------------------------"
"----------\n");
#define P_SCHEDSTAT(F) __PS(#F, schedstat_val(p->stats.F))
#define PN_SCHEDSTAT(F) __PSN(#F, schedstat_val(p->stats.F))
PN(se.exec_start);
PN(se.vruntime);
PN(se.sum_exec_runtime);
nr_switches = p->nvcsw + p->nivcsw;
P(se.nr_migrations);
if (schedstat_enabled()) {
u64 avg_atom, avg_per_cpu;
PN_SCHEDSTAT(sum_sleep_runtime);
PN_SCHEDSTAT(sum_block_runtime);
PN_SCHEDSTAT(wait_start);
PN_SCHEDSTAT(sleep_start);
PN_SCHEDSTAT(block_start);
PN_SCHEDSTAT(sleep_max);
PN_SCHEDSTAT(block_max);
PN_SCHEDSTAT(exec_max);
PN_SCHEDSTAT(slice_max);
PN_SCHEDSTAT(wait_max);
PN_SCHEDSTAT(wait_sum);
P_SCHEDSTAT(wait_count);
PN_SCHEDSTAT(iowait_sum);
P_SCHEDSTAT(iowait_count);
P_SCHEDSTAT(nr_migrations_cold);
P_SCHEDSTAT(nr_failed_migrations_affine);
P_SCHEDSTAT(nr_failed_migrations_running);
P_SCHEDSTAT(nr_failed_migrations_hot);
P_SCHEDSTAT(nr_forced_migrations);
P_SCHEDSTAT(nr_wakeups);
P_SCHEDSTAT(nr_wakeups_sync);
P_SCHEDSTAT(nr_wakeups_migrate);
P_SCHEDSTAT(nr_wakeups_local);
P_SCHEDSTAT(nr_wakeups_remote);
P_SCHEDSTAT(nr_wakeups_affine);
P_SCHEDSTAT(nr_wakeups_affine_attempts);
P_SCHEDSTAT(nr_wakeups_passive);
P_SCHEDSTAT(nr_wakeups_idle);
avg_atom = p->se.sum_exec_runtime;
if (nr_switches)
avg_atom = div64_ul(avg_atom, nr_switches);
else
avg_atom = -1LL;
avg_per_cpu = p->se.sum_exec_runtime;
if (p->se.nr_migrations) {
avg_per_cpu = div64_u64(avg_per_cpu,
p->se.nr_migrations);
} else {
avg_per_cpu = -1LL;
}
__PN(avg_atom);
__PN(avg_per_cpu);
#ifdef CONFIG_SCHED_CORE
PN_SCHEDSTAT(core_forceidle_sum);
#endif
}
__P(nr_switches);
__PS("nr_voluntary_switches", p->nvcsw);
__PS("nr_involuntary_switches", p->nivcsw);
P(se.load.weight);
#ifdef CONFIG_SMP
P(se.avg.load_sum);
P(se.avg.runnable_sum);
P(se.avg.util_sum);
P(se.avg.load_avg);
P(se.avg.runnable_avg);
P(se.avg.util_avg);
P(se.avg.last_update_time);
P(se.avg.util_est.ewma);
PM(se.avg.util_est.enqueued, ~UTIL_AVG_UNCHANGED);
#endif
#ifdef CONFIG_UCLAMP_TASK
__PS("uclamp.min", p->uclamp_req[UCLAMP_MIN].value);
__PS("uclamp.max", p->uclamp_req[UCLAMP_MAX].value);
__PS("effective uclamp.min", uclamp_eff_value(p, UCLAMP_MIN));
__PS("effective uclamp.max", uclamp_eff_value(p, UCLAMP_MAX));
#endif
P(policy);
P(prio);
if (task_has_dl_policy(p)) {
P(dl.runtime);
P(dl.deadline);
}
#undef PN_SCHEDSTAT
#undef P_SCHEDSTAT
{
unsigned int this_cpu = raw_smp_processor_id();
u64 t0, t1;
t0 = cpu_clock(this_cpu);
t1 = cpu_clock(this_cpu);
__PS("clock-delta", t1-t0);
}
sched_show_numa(p, m);
}
void proc_sched_set_task(struct task_struct *p)
{
#ifdef CONFIG_SCHEDSTATS
memset(&p->stats, 0, sizeof(p->stats));
#endif
}
void resched_latency_warn(int cpu, u64 latency)
{
static DEFINE_RATELIMIT_STATE(latency_check_ratelimit, 60 * 60 * HZ, 1);
WARN(__ratelimit(&latency_check_ratelimit),
"sched: CPU %d need_resched set for > %llu ns (%d ticks) "
"without schedule\n",
cpu, latency, cpu_rq(cpu)->ticks_without_resched);
}
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