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Merge branch 'akpm' (patches from Andrew)

Browse source 
Merge updates from Andrew Morton:

 - a few misc things

 - ocfs2 updates

 - most of MM

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (132 commits)
  hugetlbfs: dirty pages as they are added to pagecache
  mm: export add_swap_extent()
  mm: split SWP_FILE into SWP_ACTIVATED and SWP_FS
  tools/testing/selftests/vm/map_fixed_noreplace.c: add test for MAP_FIXED_NOREPLACE
  mm: thp: relocate flush_cache_range() in migrate_misplaced_transhuge_page()
  mm: thp: fix mmu_notifier in migrate_misplaced_transhuge_page()
  mm: thp: fix MADV_DONTNEED vs migrate_misplaced_transhuge_page race condition
  mm/kasan/quarantine.c: make quarantine_lock a raw_spinlock_t
  mm/gup: cache dev_pagemap while pinning pages
  Revert "x86/e820: put !E820_TYPE_RAM regions into memblock.reserved"
  mm: return zero_resv_unavail optimization
  mm: zero remaining unavailable struct pages
  tools/testing/selftests/vm/gup_benchmark.c: add MAP_HUGETLB option
  tools/testing/selftests/vm/gup_benchmark.c: add MAP_SHARED option
  tools/testing/selftests/vm/gup_benchmark.c: allow user specified file
  tools/testing/selftests/vm/gup_benchmark.c: fix 'write' flag usage
  mm/gup_benchmark.c: add additional pinning methods
  mm/gup_benchmark.c: time put_page()
  mm: don't raise MEMCG_OOM event due to failed high-order allocation
  mm/page-writeback.c: fix range_cyclic writeback vs writepages deadlock
  ...
This commit is contained in:
Linus Torvalds 2018-10-26 19:33:41 -07:00
commit 345671ea0f
156 changed files with 3400 additions and 1988 deletions
Download patch file Download diff file Expand all files Collapse all files

45
kernel/cgroup/cgroup.c
View file

@ -55,6 +55,7 @@
#include <linux/nsproxy.h>
#include <linux/file.h>
#include <linux/sched/cputime.h>
#include <linux/psi.h>
#include <net/sock.h>
#define CREATE_TRACE_POINTS
@ -862,7 +863,7 @@ static void css_set_move_task(struct task_struct *task,
*/
WARN_ON_ONCE(task->flags & PF_EXITING);
rcu_assign_pointer(task->cgroups, to_cset);
cgroup_move_task(task, to_cset);
list_add_tail(&task->cg_list, use_mg_tasks ? &to_cset->mg_tasks :
&to_cset->tasks);
}
@ -3446,6 +3447,21 @@ static int cpu_stat_show(struct seq_file *seq, void *v)
return ret;
}
#ifdef CONFIG_PSI
static int cgroup_io_pressure_show(struct seq_file *seq, void *v)
{
return psi_show(seq, &seq_css(seq)->cgroup->psi, PSI_IO);
}
static int cgroup_memory_pressure_show(struct seq_file *seq, void *v)
{
return psi_show(seq, &seq_css(seq)->cgroup->psi, PSI_MEM);
}
static int cgroup_cpu_pressure_show(struct seq_file *seq, void *v)
{
return psi_show(seq, &seq_css(seq)->cgroup->psi, PSI_CPU);
}
#endif
static int cgroup_file_open(struct kernfs_open_file *of)
{
struct cftype *cft = of->kn->priv;
@ -4576,6 +4592,23 @@ static struct cftype cgroup_base_files[] = {
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = cpu_stat_show,
},
#ifdef CONFIG_PSI
{
.name = "io.pressure",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = cgroup_io_pressure_show,
},
{
.name = "memory.pressure",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = cgroup_memory_pressure_show,
},
{
.name = "cpu.pressure",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = cgroup_cpu_pressure_show,
},
#endif
{ } /* terminate */
};
@ -4636,6 +4669,7 @@ static void css_free_rwork_fn(struct work_struct *work)
*/
cgroup_put(cgroup_parent(cgrp));
kernfs_put(cgrp->kn);
psi_cgroup_free(cgrp);
if (cgroup_on_dfl(cgrp))
cgroup_rstat_exit(cgrp);
kfree(cgrp);
@ -4892,10 +4926,15 @@ static struct cgroup *cgroup_create(struct cgroup *parent)
cgrp->self.parent = &parent->self;
cgrp->root = root;
cgrp->level = level;
ret = cgroup_bpf_inherit(cgrp);
ret = psi_cgroup_alloc(cgrp);
if (ret)
goto out_idr_free;
ret = cgroup_bpf_inherit(cgrp);
if (ret)
goto out_psi_free;
for (tcgrp = cgrp; tcgrp; tcgrp = cgroup_parent(tcgrp)) {
cgrp->ancestor_ids[tcgrp->level] = tcgrp->id;
@ -4933,6 +4972,8 @@ static struct cgroup *cgroup_create(struct cgroup *parent)
return cgrp;
out_psi_free:
psi_cgroup_free(cgrp);
out_idr_free:
cgroup_idr_remove(&root->cgroup_idr, cgrp->id);
out_stat_exit:

7
kernel/debug/kdb/kdb_main.c
View file

@ -2556,16 +2556,11 @@ static int kdb_summary(int argc, const char **argv)
}
kdb_printf("%02ld:%02ld\n", val.uptime/(60*60), (val.uptime/60)%60);
/* lifted from fs/proc/proc_misc.c::loadavg_read_proc() */
#define LOAD_INT(x) ((x) >> FSHIFT)
#define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)
kdb_printf("load avg %ld.%02ld %ld.%02ld %ld.%02ld\n",
LOAD_INT(val.loads[0]), LOAD_FRAC(val.loads[0]),
LOAD_INT(val.loads[1]), LOAD_FRAC(val.loads[1]),
LOAD_INT(val.loads[2]), LOAD_FRAC(val.loads[2]));
#undef LOAD_INT
#undef LOAD_FRAC
/* Display in kilobytes */
#define K(x) ((x) << (PAGE_SHIFT - 10))
kdb_printf("\nMemTotal: %8lu kB\nMemFree: %8lu kB\n"

15
kernel/delayacct.c
View file

@ -135,9 +135,12 @@ int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
tmp = d->freepages_delay_total + tsk->delays->freepages_delay;
d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp;
tmp = d->thrashing_delay_total + tsk->delays->thrashing_delay;
d->thrashing_delay_total = (tmp < d->thrashing_delay_total) ? 0 : tmp;
d->blkio_count += tsk->delays->blkio_count;
d->swapin_count += tsk->delays->swapin_count;
d->freepages_count += tsk->delays->freepages_count;
d->thrashing_count += tsk->delays->thrashing_count;
raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
return 0;
@ -169,3 +172,15 @@ void __delayacct_freepages_end(void)
&current->delays->freepages_count);
}
void __delayacct_thrashing_start(void)
{
current->delays->thrashing_start = ktime_get_ns();
}
void __delayacct_thrashing_end(void)
{
delayacct_end(&current->delays->lock,
&current->delays->thrashing_start,
&current->delays->thrashing_delay,
&current->delays->thrashing_count);
}

59
kernel/fork.c
View file

@ -223,9 +223,14 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
return s->addr;
}
/*
* Allocated stacks are cached and later reused by new threads,
* so memcg accounting is performed manually on assigning/releasing
* stacks to tasks. Drop __GFP_ACCOUNT.
*/
stack = __vmalloc_node_range(THREAD_SIZE, THREAD_ALIGN,
VMALLOC_START, VMALLOC_END,
THREADINFO_GFP,
THREADINFO_GFP & ~__GFP_ACCOUNT,
PAGE_KERNEL,
0, node, __builtin_return_address(0));
@ -248,9 +253,19 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
static inline void free_thread_stack(struct task_struct *tsk)
{
#ifdef CONFIG_VMAP_STACK
if (task_stack_vm_area(tsk)) {
struct vm_struct *vm = task_stack_vm_area(tsk);
if (vm) {
int i;
for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) {
mod_memcg_page_state(vm->pages[i],
MEMCG_KERNEL_STACK_KB,
-(int)(PAGE_SIZE / 1024));
memcg_kmem_uncharge(vm->pages[i], 0);
}
for (i = 0; i < NR_CACHED_STACKS; i++) {
if (this_cpu_cmpxchg(cached_stacks[i],
NULL, tsk->stack_vm_area) != NULL)
@ -351,10 +366,6 @@ static void account_kernel_stack(struct task_struct *tsk, int account)
NR_KERNEL_STACK_KB,
PAGE_SIZE / 1024 * account);
}
/* All stack pages belong to the same memcg. */
mod_memcg_page_state(vm->pages[0], MEMCG_KERNEL_STACK_KB,
account * (THREAD_SIZE / 1024));
} else {
/*
* All stack pages are in the same zone and belong to the
@ -370,6 +381,35 @@ static void account_kernel_stack(struct task_struct *tsk, int account)
}
}
static int memcg_charge_kernel_stack(struct task_struct *tsk)
{
#ifdef CONFIG_VMAP_STACK
struct vm_struct *vm = task_stack_vm_area(tsk);
int ret;
if (vm) {
int i;
for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) {
/*
* If memcg_kmem_charge() fails, page->mem_cgroup
* pointer is NULL, and both memcg_kmem_uncharge()
* and mod_memcg_page_state() in free_thread_stack()
* will ignore this page. So it's safe.
*/
ret = memcg_kmem_charge(vm->pages[i], GFP_KERNEL, 0);
if (ret)
return ret;
mod_memcg_page_state(vm->pages[i],
MEMCG_KERNEL_STACK_KB,
PAGE_SIZE / 1024);
}
}
#endif
return 0;
}
static void release_task_stack(struct task_struct *tsk)
{
if (WARN_ON(tsk->state != TASK_DEAD))
@ -807,6 +847,9 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
if (!stack)
goto free_tsk;
if (memcg_charge_kernel_stack(tsk))
goto free_stack;
stack_vm_area = task_stack_vm_area(tsk);
err = arch_dup_task_struct(tsk, orig);
@ -1779,6 +1822,10 @@ static __latent_entropy struct task_struct *copy_process(
p->default_timer_slack_ns = current->timer_slack_ns;
#ifdef CONFIG_PSI
p->psi_flags = 0;
#endif
task_io_accounting_init(&p->ioac);
acct_clear_integrals(p);

27
kernel/memremap.c
View file

@ -175,10 +175,10 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
struct vmem_altmap *altmap = pgmap->altmap_valid ?
&pgmap->altmap : NULL;
struct resource *res = &pgmap->res;
unsigned long pfn, pgoff, order;
pgprot_t pgprot = PAGE_KERNEL;
int error, nid, is_ram;
struct dev_pagemap *conflict_pgmap;
pgprot_t pgprot = PAGE_KERNEL;
unsigned long pgoff, order;
int error, nid, is_ram;
align_start = res->start & ~(SECTION_SIZE - 1);
align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
@ -256,19 +256,14 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
if (error)
goto err_add_memory;
for_each_device_pfn(pfn, pgmap) {
struct page *page = pfn_to_page(pfn);
/*
* ZONE_DEVICE pages union ->lru with a ->pgmap back
* pointer. It is a bug if a ZONE_DEVICE page is ever
* freed or placed on a driver-private list. Seed the
* storage with LIST_POISON* values.
*/
list_del(&page->lru);
page->pgmap = pgmap;
percpu_ref_get(pgmap->ref);
}
/*
* Initialization of the pages has been deferred until now in order
* to allow us to do the work while not holding the hotplug lock.
*/
memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
align_start >> PAGE_SHIFT,
align_size >> PAGE_SHIFT, pgmap);
percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap));
devm_add_action(dev, devm_memremap_pages_release, pgmap);

1
kernel/sched/Makefile
View file

@ -29,3 +29,4 @@ obj-$(CONFIG_CPU_FREQ) += cpufreq.o
obj-$(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) += cpufreq_schedutil.o
obj-$(CONFIG_MEMBARRIER) += membarrier.o
obj-$(CONFIG_CPU_ISOLATION) += isolation.o
obj-$(CONFIG_PSI) += psi.o

16
kernel/sched/core.c
View file

@ -722,8 +722,10 @@ static inline void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
if (!(flags & ENQUEUE_NOCLOCK))
update_rq_clock(rq);
if (!(flags & ENQUEUE_RESTORE))
if (!(flags & ENQUEUE_RESTORE)) {
sched_info_queued(rq, p);
psi_enqueue(p, flags & ENQUEUE_WAKEUP);
}
p->sched_class->enqueue_task(rq, p, flags);
}
@ -733,8 +735,10 @@ static inline void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
if (!(flags & DEQUEUE_NOCLOCK))
update_rq_clock(rq);
if (!(flags & DEQUEUE_SAVE))
if (!(flags & DEQUEUE_SAVE)) {
sched_info_dequeued(rq, p);
psi_dequeue(p, flags & DEQUEUE_SLEEP);
}
p->sched_class->dequeue_task(rq, p, flags);
}
@ -2037,6 +2041,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags);
if (task_cpu(p) != cpu) {
wake_flags |= WF_MIGRATED;
psi_ttwu_dequeue(p);
set_task_cpu(p, cpu);
}
@ -3051,6 +3056,7 @@ void scheduler_tick(void)
curr->sched_class->task_tick(rq, curr, 0);
cpu_load_update_active(rq);
calc_global_load_tick(rq);
psi_task_tick(rq);
rq_unlock(rq, &rf);
@ -4933,9 +4939,7 @@ static void do_sched_yield(void)
struct rq_flags rf;
struct rq *rq;
local_irq_disable();
rq = this_rq();
rq_lock(rq, &rf);
rq = this_rq_lock_irq(&rf);
schedstat_inc(rq->yld_count);
current->sched_class->yield_task(rq);
@ -6069,6 +6073,8 @@ void __init sched_init(void)
init_schedstats();
psi_init();
scheduler_running = 1;
}

139
kernel/sched/loadavg.c
View file

@ -91,19 +91,73 @@ long calc_load_fold_active(struct rq *this_rq, long adjust)
return delta;
}
/*
* a1 = a0 * e + a * (1 - e)
/**
* fixed_power_int - compute: x^n, in O(log n) time
*
* @x: base of the power
* @frac_bits: fractional bits of @x
* @n: power to raise @x to.
*
* By exploiting the relation between the definition of the natural power
* function: x^n := x*x*...*x (x multiplied by itself for n times), and
* the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
* (where: n_i \elem {0, 1}, the binary vector representing n),
* we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
* of course trivially computable in O(log_2 n), the length of our binary
* vector.
*/
static unsigned long
calc_load(unsigned long load, unsigned long exp, unsigned long active)
fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n)
{
unsigned long newload;
unsigned long result = 1UL << frac_bits;
newload = load * exp + active * (FIXED_1 - exp);
if (active >= load)
newload += FIXED_1-1;
if (n) {
for (;;) {
if (n & 1) {
result *= x;
result += 1UL << (frac_bits - 1);
result >>= frac_bits;
}
n >>= 1;
if (!n)
break;
x *= x;
x += 1UL << (frac_bits - 1);
x >>= frac_bits;
}
}
return newload / FIXED_1;
return result;
}
/*
* a1 = a0 * e + a * (1 - e)
*
* a2 = a1 * e + a * (1 - e)
* = (a0 * e + a * (1 - e)) * e + a * (1 - e)
* = a0 * e^2 + a * (1 - e) * (1 + e)
*
* a3 = a2 * e + a * (1 - e)
* = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
* = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
*
* ...
*
* an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
* = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
* = a0 * e^n + a * (1 - e^n)
*
* [1] application of the geometric series:
*
* n 1 - x^(n+1)
* S_n := \Sum x^i = -------------
* i=0 1 - x
*/
unsigned long
calc_load_n(unsigned long load, unsigned long exp,
unsigned long active, unsigned int n)
{
return calc_load(load, fixed_power_int(exp, FSHIFT, n), active);
}
#ifdef CONFIG_NO_HZ_COMMON
@ -225,75 +279,6 @@ static long calc_load_nohz_fold(void)
return delta;
}
/**
* fixed_power_int - compute: x^n, in O(log n) time
*
* @x: base of the power
* @frac_bits: fractional bits of @x
* @n: power to raise @x to.
*
* By exploiting the relation between the definition of the natural power
* function: x^n := x*x*...*x (x multiplied by itself for n times), and
* the binary encoding of numbers used by computers: n := \Sum n_i * 2^i,
* (where: n_i \elem {0, 1}, the binary vector representing n),
* we find: x^n := x^(\Sum n_i * 2^i) := \Prod x^(n_i * 2^i), which is
* of course trivially computable in O(log_2 n), the length of our binary
* vector.
*/
static unsigned long
fixed_power_int(unsigned long x, unsigned int frac_bits, unsigned int n)
{
unsigned long result = 1UL << frac_bits;
if (n) {
for (;;) {
if (n & 1) {
result *= x;
result += 1UL << (frac_bits - 1);
result >>= frac_bits;
}
n >>= 1;
if (!n)
break;
x *= x;
x += 1UL << (frac_bits - 1);
x >>= frac_bits;
}
}
return result;
}
/*
* a1 = a0 * e + a * (1 - e)
*
* a2 = a1 * e + a * (1 - e)
* = (a0 * e + a * (1 - e)) * e + a * (1 - e)
* = a0 * e^2 + a * (1 - e) * (1 + e)
*
* a3 = a2 * e + a * (1 - e)
* = (a0 * e^2 + a * (1 - e) * (1 + e)) * e + a * (1 - e)
* = a0 * e^3 + a * (1 - e) * (1 + e + e^2)
*
* ...
*
* an = a0 * e^n + a * (1 - e) * (1 + e + ... + e^n-1) [1]
* = a0 * e^n + a * (1 - e) * (1 - e^n)/(1 - e)
* = a0 * e^n + a * (1 - e^n)
*
* [1] application of the geometric series:
*
* n 1 - x^(n+1)
* S_n := \Sum x^i = -------------
* i=0 1 - x
*/
static unsigned long
calc_load_n(unsigned long load, unsigned long exp,
unsigned long active, unsigned int n)
{
return calc_load(load, fixed_power_int(exp, FSHIFT, n), active);
}
/*
* NO_HZ can leave us missing all per-CPU ticks calling
* calc_load_fold_active(), but since a NO_HZ CPU folds its delta into

759
kernel/sched/psi.c Normal file
View file

@ -0,0 +1,759 @@
/*
* Pressure stall information for CPU, memory and IO
*
* Copyright (c) 2018 Facebook, Inc.
* Author: Johannes Weiner <hannes@cmpxchg.org>
*
* When CPU, memory and IO are contended, tasks experience delays that
* reduce throughput and introduce latencies into the workload. Memory
* and IO contention, in addition, can cause a full loss of forward
* progress in which the CPU goes idle.
*
* This code aggregates individual task delays into resource pressure
* metrics that indicate problems with both workload health and
* resource utilization.
*
* Model
*
* The time in which a task can execute on a CPU is our baseline for
* productivity. Pressure expresses the amount of time in which this
* potential cannot be realized due to resource contention.
*
* This concept of productivity has two components: the workload and
* the CPU. To measure the impact of pressure on both, we define two
* contention states for a resource: SOME and FULL.
*
* In the SOME state of a given resource, one or more tasks are
* delayed on that resource. This affects the workload's ability to
* perform work, but the CPU may still be executing other tasks.
*
* In the FULL state of a given resource, all non-idle tasks are
* delayed on that resource such that nobody is advancing and the CPU
* goes idle. This leaves both workload and CPU unproductive.
*
* (Naturally, the FULL state doesn't exist for the CPU resource.)
*
* SOME = nr_delayed_tasks != 0
* FULL = nr_delayed_tasks != 0 && nr_running_tasks == 0
*
* The percentage of wallclock time spent in those compound stall
* states gives pressure numbers between 0 and 100 for each resource,
* where the SOME percentage indicates workload slowdowns and the FULL
* percentage indicates reduced CPU utilization:
*
* %SOME = time(SOME) / period
* %FULL = time(FULL) / period
*
* Multiple CPUs
*
* The more tasks and available CPUs there are, the more work can be
* performed concurrently. This means that the potential that can go
* unrealized due to resource contention *also* scales with non-idle
* tasks and CPUs.
*
* Consider a scenario where 257 number crunching tasks are trying to
* run concurrently on 256 CPUs. If we simply aggregated the task
* states, we would have to conclude a CPU SOME pressure number of
* 100%, since *somebody* is waiting on a runqueue at all
* times. However, that is clearly not the amount of contention the
* workload is experiencing: only one out of 256 possible exceution
* threads will be contended at any given time, or about 0.4%.
*
* Conversely, consider a scenario of 4 tasks and 4 CPUs where at any
* given time *one* of the tasks is delayed due to a lack of memory.
* Again, looking purely at the task state would yield a memory FULL
* pressure number of 0%, since *somebody* is always making forward
* progress. But again this wouldn't capture the amount of execution
* potential lost, which is 1 out of 4 CPUs, or 25%.
*
* To calculate wasted potential (pressure) with multiple processors,
* we have to base our calculation on the number of non-idle tasks in
* conjunction with the number of available CPUs, which is the number
* of potential execution threads. SOME becomes then the proportion of
* delayed tasks to possibe threads, and FULL is the share of possible
* threads that are unproductive due to delays:
*
* threads = min(nr_nonidle_tasks, nr_cpus)
* SOME = min(nr_delayed_tasks / threads, 1)
* FULL = (threads - min(nr_running_tasks, threads)) / threads
*
* For the 257 number crunchers on 256 CPUs, this yields:
*
* threads = min(257, 256)
* SOME = min(1 / 256, 1) = 0.4%
* FULL = (256 - min(257, 256)) / 256 = 0%
*
* For the 1 out of 4 memory-delayed tasks, this yields:
*
* threads = min(4, 4)
* SOME = min(1 / 4, 1) = 25%
* FULL = (4 - min(3, 4)) / 4 = 25%
*
* [ Substitute nr_cpus with 1, and you can see that it's a natural
* extension of the single-CPU model. ]
*
* Implementation
*
* To assess the precise time spent in each such state, we would have
* to freeze the system on task changes and start/stop the state
* clocks accordingly. Obviously that doesn't scale in practice.
*
* Because the scheduler aims to distribute the compute load evenly
* among the available CPUs, we can track task state locally to each
* CPU and, at much lower frequency, extrapolate the global state for
* the cumulative stall times and the running averages.
*
* For each runqueue, we track:
*
* tSOME[cpu] = time(nr_delayed_tasks[cpu] != 0)
* tFULL[cpu] = time(nr_delayed_tasks[cpu] && !nr_running_tasks[cpu])
* tNONIDLE[cpu] = time(nr_nonidle_tasks[cpu] != 0)
*
* and then periodically aggregate:
*
* tNONIDLE = sum(tNONIDLE[i])
*
* tSOME = sum(tSOME[i] * tNONIDLE[i]) / tNONIDLE
* tFULL = sum(tFULL[i] * tNONIDLE[i]) / tNONIDLE
*
* %SOME = tSOME / period
* %FULL = tFULL / period
*
* This gives us an approximation of pressure that is practical
* cost-wise, yet way more sensitive and accurate than periodic
* sampling of the aggregate task states would be.
*/
#include <linux/sched/loadavg.h>
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
#include <linux/seqlock.h>
#include <linux/cgroup.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/psi.h>
#include "sched.h"
static int psi_bug __read_mostly;
bool psi_disabled __read_mostly;
core_param(psi_disabled, psi_disabled, bool, 0644);
/* Running averages - we need to be higher-res than loadavg */
#define PSI_FREQ (2*HZ+1) /* 2 sec intervals */
#define EXP_10s 1677 /* 1/exp(2s/10s) as fixed-point */
#define EXP_60s 1981 /* 1/exp(2s/60s) */
#define EXP_300s 2034 /* 1/exp(2s/300s) */
/* Sampling frequency in nanoseconds */
static u64 psi_period __read_mostly;
/* System-level pressure and stall tracking */
static DEFINE_PER_CPU(struct psi_group_cpu, system_group_pcpu);
static struct psi_group psi_system = {
.pcpu = &system_group_pcpu,
};
static void psi_update_work(struct work_struct *work);
static void group_init(struct psi_group *group)
{
int cpu;
for_each_possible_cpu(cpu)
seqcount_init(&per_cpu_ptr(group->pcpu, cpu)->seq);
group->next_update = sched_clock() + psi_period;
INIT_DELAYED_WORK(&group->clock_work, psi_update_work);
mutex_init(&group->stat_lock);
}
void __init psi_init(void)
{
if (psi_disabled)
return;
psi_period = jiffies_to_nsecs(PSI_FREQ);
group_init(&psi_system);
}
static bool test_state(unsigned int *tasks, enum psi_states state)
{
switch (state) {
case PSI_IO_SOME:
return tasks[NR_IOWAIT];
case PSI_IO_FULL:
return tasks[NR_IOWAIT] && !tasks[NR_RUNNING];
case PSI_MEM_SOME:
return tasks[NR_MEMSTALL];
case PSI_MEM_FULL:
return tasks[NR_MEMSTALL] && !tasks[NR_RUNNING];
case PSI_CPU_SOME:
return tasks[NR_RUNNING] > 1;
case PSI_NONIDLE:
return tasks[NR_IOWAIT] || tasks[NR_MEMSTALL] ||
tasks[NR_RUNNING];
default:
return false;
}
}
static void get_recent_times(struct psi_group *group, int cpu, u32 *times)
{
struct psi_group_cpu *groupc = per_cpu_ptr(group->pcpu, cpu);
unsigned int tasks[NR_PSI_TASK_COUNTS];
u64 now, state_start;
unsigned int seq;
int s;
/* Snapshot a coherent view of the CPU state */
do {
seq = read_seqcount_begin(&groupc->seq);
now = cpu_clock(cpu);
memcpy(times, groupc->times, sizeof(groupc->times));
memcpy(tasks, groupc->tasks, sizeof(groupc->tasks));
state_start = groupc->state_start;
} while (read_seqcount_retry(&groupc->seq, seq));
/* Calculate state time deltas against the previous snapshot */
for (s = 0; s < NR_PSI_STATES; s++) {
u32 delta;
/*
* In addition to already concluded states, we also
* incorporate currently active states on the CPU,
* since states may last for many sampling periods.
*
* This way we keep our delta sampling buckets small
* (u32) and our reported pressure close to what's
* actually happening.
*/
if (test_state(tasks, s))
times[s] += now - state_start;
delta = times[s] - groupc->times_prev[s];
groupc->times_prev[s] = times[s];
times[s] = delta;
}
}
static void calc_avgs(unsigned long avg[3], int missed_periods,
u64 time, u64 period)
{
unsigned long pct;
/* Fill in zeroes for periods of no activity */
if (missed_periods) {
avg[0] = calc_load_n(avg[0], EXP_10s, 0, missed_periods);
avg[1] = calc_load_n(avg[1], EXP_60s, 0, missed_periods);
avg[2] = calc_load_n(avg[2], EXP_300s, 0, missed_periods);
}
/* Sample the most recent active period */
pct = div_u64(time * 100, period);
pct *= FIXED_1;
avg[0] = calc_load(avg[0], EXP_10s, pct);
avg[1] = calc_load(avg[1], EXP_60s, pct);
avg[2] = calc_load(avg[2], EXP_300s, pct);
}
static bool update_stats(struct psi_group *group)
{
u64 deltas[NR_PSI_STATES - 1] = { 0, };
unsigned long missed_periods = 0;
unsigned long nonidle_total = 0;
u64 now, expires, period;
int cpu;
int s;
mutex_lock(&group->stat_lock);
/*
* Collect the per-cpu time buckets and average them into a
* single time sample that is normalized to wallclock time.
*
* For averaging, each CPU is weighted by its non-idle time in
* the sampling period. This eliminates artifacts from uneven
* loading, or even entirely idle CPUs.
*/
for_each_possible_cpu(cpu) {
u32 times[NR_PSI_STATES];
u32 nonidle;
get_recent_times(group, cpu, times);
nonidle = nsecs_to_jiffies(times[PSI_NONIDLE]);
nonidle_total += nonidle;
for (s = 0; s < PSI_NONIDLE; s++)
deltas[s] += (u64)times[s] * nonidle;
}
/*
* Integrate the sample into the running statistics that are
* reported to userspace: the cumulative stall times and the
* decaying averages.
*
* Pressure percentages are sampled at PSI_FREQ. We might be
* called more often when the user polls more frequently than
* that; we might be called less often when there is no task
* activity, thus no data, and clock ticks are sporadic. The
* below handles both.
*/
/* total= */
for (s = 0; s < NR_PSI_STATES - 1; s++)
group->total[s] += div_u64(deltas[s], max(nonidle_total, 1UL));
/* avgX= */
now = sched_clock();
expires = group->next_update;
if (now < expires)
goto out;
if (now - expires > psi_period)
missed_periods = div_u64(now - expires, psi_period);
/*
* The periodic clock tick can get delayed for various
* reasons, especially on loaded systems. To avoid clock
* drift, we schedule the clock in fixed psi_period intervals.
* But the deltas we sample out of the per-cpu buckets above
* are based on the actual time elapsing between clock ticks.
*/
group->next_update = expires + ((1 + missed_periods) * psi_period);
period = now - (group->last_update + (missed_periods * psi_period));
group->last_update = now;
for (s = 0; s < NR_PSI_STATES - 1; s++) {
u32 sample;
sample = group->total[s] - group->total_prev[s];
/*
* Due to the lockless sampling of the time buckets,
* recorded time deltas can slip into the next period,
* which under full pressure can result in samples in
* excess of the period length.
*
* We don't want to report non-sensical pressures in
* excess of 100%, nor do we want to drop such events
* on the floor. Instead we punt any overage into the
* future until pressure subsides. By doing this we
* don't underreport the occurring pressure curve, we
* just report it delayed by one period length.
*
* The error isn't cumulative. As soon as another
* delta slips from a period P to P+1, by definition
* it frees up its time T in P.
*/
if (sample > period)
sample = period;
group->total_prev[s] += sample;
calc_avgs(group->avg[s], missed_periods, sample, period);
}
out:
mutex_unlock(&group->stat_lock);
return nonidle_total;
}
static void psi_update_work(struct work_struct *work)
{
struct delayed_work *dwork;
struct psi_group *group;
bool nonidle;
dwork = to_delayed_work(work);
group = container_of(dwork, struct psi_group, clock_work);
/*
* If there is task activity, periodically fold the per-cpu
* times and feed samples into the running averages. If things
* are idle and there is no data to process, stop the clock.
* Once restarted, we'll catch up the running averages in one
* go - see calc_avgs() and missed_periods.
*/
nonidle = update_stats(group);
if (nonidle) {
unsigned long delay = 0;
u64 now;
now = sched_clock();
if (group->next_update > now)
delay = nsecs_to_jiffies(group->next_update - now) + 1;
schedule_delayed_work(dwork, delay);
}
}
static void record_times(struct psi_group_cpu *groupc, int cpu,
bool memstall_tick)
{
u32 delta;
u64 now;
now = cpu_clock(cpu);
delta = now - groupc->state_start;
groupc->state_start = now;
if (test_state(groupc->tasks, PSI_IO_SOME)) {
groupc->times[PSI_IO_SOME] += delta;
if (test_state(groupc->tasks, PSI_IO_FULL))
groupc->times[PSI_IO_FULL] += delta;
}
if (test_state(groupc->tasks, PSI_MEM_SOME)) {
groupc->times[PSI_MEM_SOME] += delta;
if (test_state(groupc->tasks, PSI_MEM_FULL))
groupc->times[PSI_MEM_FULL] += delta;
else if (memstall_tick) {
u32 sample;
/*
* Since we care about lost potential, a
* memstall is FULL when there are no other
* working tasks, but also when the CPU is
* actively reclaiming and nothing productive
* could run even if it were runnable.
*
* When the timer tick sees a reclaiming CPU,
* regardless of runnable tasks, sample a FULL
* tick (or less if it hasn't been a full tick
* since the last state change).
*/
sample = min(delta, (u32)jiffies_to_nsecs(1));
groupc->times[PSI_MEM_FULL] += sample;
}
}
if (test_state(groupc->tasks, PSI_CPU_SOME))
groupc->times[PSI_CPU_SOME] += delta;
if (test_state(groupc->tasks, PSI_NONIDLE))
groupc->times[PSI_NONIDLE] += delta;
}
static void psi_group_change(struct psi_group *group, int cpu,
unsigned int clear, unsigned int set)
{
struct psi_group_cpu *groupc;
unsigned int t, m;
groupc = per_cpu_ptr(group->pcpu, cpu);
/*
* First we assess the aggregate resource states this CPU's
* tasks have been in since the last change, and account any
* SOME and FULL time these may have resulted in.
*
* Then we update the task counts according to the state
* change requested through the @clear and @set bits.
*/
write_seqcount_begin(&groupc->seq);
record_times(groupc, cpu, false);
for (t = 0, m = clear; m; m &= ~(1 << t), t++) {
if (!(m & (1 << t)))
continue;
if (groupc->tasks[t] == 0 && !psi_bug) {
printk_deferred(KERN_ERR "psi: task underflow! cpu=%d t=%d tasks=[%u %u %u] clear=%x set=%x\n",
cpu, t, groupc->tasks[0],
groupc->tasks[1], groupc->tasks[2],
clear, set);
psi_bug = 1;
}
groupc->tasks[t]--;
}
for (t = 0; set; set &= ~(1 << t), t++)
if (set & (1 << t))
groupc->tasks[t]++;
write_seqcount_end(&groupc->seq);
if (!delayed_work_pending(&group->clock_work))
schedule_delayed_work(&group->clock_work, PSI_FREQ);
}
static struct psi_group *iterate_groups(struct task_struct *task, void **iter)
{
#ifdef CONFIG_CGROUPS
struct cgroup *cgroup = NULL;
if (!*iter)
cgroup = task->cgroups->dfl_cgrp;
else if (*iter == &psi_system)
return NULL;
else
cgroup = cgroup_parent(*iter);
if (cgroup && cgroup_parent(cgroup)) {
*iter = cgroup;
return cgroup_psi(cgroup);
}
#else
if (*iter)
return NULL;
#endif
*iter = &psi_system;
return &psi_system;
}
void psi_task_change(struct task_struct *task, int clear, int set)
{
int cpu = task_cpu(task);
struct psi_group *group;
void *iter = NULL;
if (!task->pid)
return;
if (((task->psi_flags & set) ||
(task->psi_flags & clear) != clear) &&
!psi_bug) {
printk_deferred(KERN_ERR "psi: inconsistent task state! task=%d:%s cpu=%d psi_flags=%x clear=%x set=%x\n",
task->pid, task->comm, cpu,
task->psi_flags, clear, set);
psi_bug = 1;
}
task->psi_flags &= ~clear;
task->psi_flags |= set;
while ((group = iterate_groups(task, &iter)))
psi_group_change(group, cpu, clear, set);
}
void psi_memstall_tick(struct task_struct *task, int cpu)
{
struct psi_group *group;
void *iter = NULL;
while ((group = iterate_groups(task, &iter))) {
struct psi_group_cpu *groupc;
groupc = per_cpu_ptr(group->pcpu, cpu);
write_seqcount_begin(&groupc->seq);
record_times(groupc, cpu, true);
write_seqcount_end(&groupc->seq);
}
}
/**
* psi_memstall_enter - mark the beginning of a memory stall section
* @flags: flags to handle nested sections
*
* Marks the calling task as being stalled due to a lack of memory,
* such as waiting for a refault or performing reclaim.
*/
void psi_memstall_enter(unsigned long *flags)
{
struct rq_flags rf;
struct rq *rq;
if (psi_disabled)
return;
*flags = current->flags & PF_MEMSTALL;
if (*flags)
return;
/*
* PF_MEMSTALL setting & accounting needs to be atomic wrt
* changes to the task's scheduling state, otherwise we can
* race with CPU migration.
*/
rq = this_rq_lock_irq(&rf);
current->flags |= PF_MEMSTALL;
psi_task_change(current, 0, TSK_MEMSTALL);
rq_unlock_irq(rq, &rf);
}
/**
* psi_memstall_leave - mark the end of an memory stall section
* @flags: flags to handle nested memdelay sections
*
* Marks the calling task as no longer stalled due to lack of memory.
*/
void psi_memstall_leave(unsigned long *flags)
{
struct rq_flags rf;
struct rq *rq;
if (psi_disabled)
return;
if (*flags)
return;
/*
* PF_MEMSTALL clearing & accounting needs to be atomic wrt
* changes to the task's scheduling state, otherwise we could
* race with CPU migration.
*/
rq = this_rq_lock_irq(&rf);
current->flags &= ~PF_MEMSTALL;
psi_task_change(current, TSK_MEMSTALL, 0);
rq_unlock_irq(rq, &rf);
}
#ifdef CONFIG_CGROUPS
int psi_cgroup_alloc(struct cgroup *cgroup)
{
if (psi_disabled)
return 0;
cgroup->psi.pcpu = alloc_percpu(struct psi_group_cpu);
if (!cgroup->psi.pcpu)
return -ENOMEM;
group_init(&cgroup->psi);
return 0;
}
void psi_cgroup_free(struct cgroup *cgroup)
{
if (psi_disabled)
return;
cancel_delayed_work_sync(&cgroup->psi.clock_work);
free_percpu(cgroup->psi.pcpu);
}
/**
* cgroup_move_task - move task to a different cgroup
* @task: the task
* @to: the target css_set
*
* Move task to a new cgroup and safely migrate its associated stall
* state between the different groups.
*
* This function acquires the task's rq lock to lock out concurrent
* changes to the task's scheduling state and - in case the task is
* running - concurrent changes to its stall state.
*/
void cgroup_move_task(struct task_struct *task, struct css_set *to)
{
bool move_psi = !psi_disabled;
unsigned int task_flags = 0;
struct rq_flags rf;
struct rq *rq;
if (move_psi) {
rq = task_rq_lock(task, &rf);
if (task_on_rq_queued(task))
task_flags = TSK_RUNNING;
else if (task->in_iowait)
task_flags = TSK_IOWAIT;
if (task->flags & PF_MEMSTALL)
task_flags |= TSK_MEMSTALL;
if (task_flags)
psi_task_change(task, task_flags, 0);
}
/*
* Lame to do this here, but the scheduler cannot be locked
* from the outside, so we move cgroups from inside sched/.
*/
rcu_assign_pointer(task->cgroups, to);
if (move_psi) {
if (task_flags)
psi_task_change(task, 0, task_flags);
task_rq_unlock(rq, task, &rf);
}
}
#endif /* CONFIG_CGROUPS */
int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res)
{
int full;
if (psi_disabled)
return -EOPNOTSUPP;
update_stats(group);
for (full = 0; full < 2 - (res == PSI_CPU); full++) {
unsigned long avg[3];
u64 total;
int w;
for (w = 0; w < 3; w++)
avg[w] = group->avg[res * 2 + full][w];
total = div_u64(group->total[res * 2 + full], NSEC_PER_USEC);
seq_printf(m, "%s avg10=%lu.%02lu avg60=%lu.%02lu avg300=%lu.%02lu total=%llu\n",
full ? "full" : "some",
LOAD_INT(avg[0]), LOAD_FRAC(avg[0]),
LOAD_INT(avg[1]), LOAD_FRAC(avg[1]),
LOAD_INT(avg[2]), LOAD_FRAC(avg[2]),
total);
}
return 0;
}
static int psi_io_show(struct seq_file *m, void *v)
{
return psi_show(m, &psi_system, PSI_IO);
}
static int psi_memory_show(struct seq_file *m, void *v)
{
return psi_show(m, &psi_system, PSI_MEM);
}
static int psi_cpu_show(struct seq_file *m, void *v)
{
return psi_show(m, &psi_system, PSI_CPU);
}
static int psi_io_open(struct inode *inode, struct file *file)
{
return single_open(file, psi_io_show, NULL);
}
static int psi_memory_open(struct inode *inode, struct file *file)
{
return single_open(file, psi_memory_show, NULL);
}
static int psi_cpu_open(struct inode *inode, struct file *file)
{
return single_open(file, psi_cpu_show, NULL);
}
static const struct file_operations psi_io_fops = {
.open = psi_io_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static const struct file_operations psi_memory_fops = {
.open = psi_memory_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static const struct file_operations psi_cpu_fops = {
.open = psi_cpu_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int __init psi_proc_init(void)
{
proc_mkdir("pressure", NULL);
proc_create("pressure/io", 0, NULL, &psi_io_fops);
proc_create("pressure/memory", 0, NULL, &psi_memory_fops);
proc_create("pressure/cpu", 0, NULL, &psi_cpu_fops);
return 0;
}
module_init(psi_proc_init);

178
kernel/sched/sched.h
View file

@ -54,6 +54,7 @@
#include <linux/proc_fs.h>
#include <linux/prefetch.h>
#include <linux/profile.h>
#include <linux/psi.h>
#include <linux/rcupdate_wait.h>
#include <linux/security.h>
#include <linux/stop_machine.h>
@ -319,6 +320,7 @@ extern bool dl_cpu_busy(unsigned int cpu);
#ifdef CONFIG_CGROUP_SCHED
#include <linux/cgroup.h>
#include <linux/psi.h>
struct cfs_rq;
struct rt_rq;
@ -957,6 +959,8 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
#define cpu_curr(cpu) (cpu_rq(cpu)->curr)
#define raw_rq() raw_cpu_ptr(&runqueues)
extern void update_rq_clock(struct rq *rq);
static inline u64 __rq_clock_broken(struct rq *rq)
{
return READ_ONCE(rq->clock);
@ -1075,6 +1079,98 @@ static inline void rq_repin_lock(struct rq *rq, struct rq_flags *rf)
#endif
}
struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
__acquires(rq->lock);
struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
__acquires(p->pi_lock)
__acquires(rq->lock);
static inline void __task_rq_unlock(struct rq *rq, struct rq_flags *rf)
__releases(rq->lock)
{
rq_unpin_lock(rq, rf);
raw_spin_unlock(&rq->lock);
}
static inline void
task_rq_unlock(struct rq *rq, struct task_struct *p, struct rq_flags *rf)
__releases(rq->lock)
__releases(p->pi_lock)
{
rq_unpin_lock(rq, rf);
raw_spin_unlock(&rq->lock);
raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
}
static inline void
rq_lock_irqsave(struct rq *rq, struct rq_flags *rf)
__acquires(rq->lock)
{
raw_spin_lock_irqsave(&rq->lock, rf->flags);
rq_pin_lock(rq, rf);
}
static inline void
rq_lock_irq(struct rq *rq, struct rq_flags *rf)
__acquires(rq->lock)
{
raw_spin_lock_irq(&rq->lock);
rq_pin_lock(rq, rf);
}
static inline void
rq_lock(struct rq *rq, struct rq_flags *rf)
__acquires(rq->lock)
{
raw_spin_lock(&rq->lock);
rq_pin_lock(rq, rf);
}
static inline void
rq_relock(struct rq *rq, struct rq_flags *rf)
__acquires(rq->lock)
{
raw_spin_lock(&rq->lock);
rq_repin_lock(rq, rf);
}
static inline void
rq_unlock_irqrestore(struct rq *rq, struct rq_flags *rf)
__releases(rq->lock)
{
rq_unpin_lock(rq, rf);
raw_spin_unlock_irqrestore(&rq->lock, rf->flags);
}
static inline void
rq_unlock_irq(struct rq *rq, struct rq_flags *rf)
__releases(rq->lock)
{
rq_unpin_lock(rq, rf);
raw_spin_unlock_irq(&rq->lock);
}
static inline void
rq_unlock(struct rq *rq, struct rq_flags *rf)
__releases(rq->lock)
{
rq_unpin_lock(rq, rf);
raw_spin_unlock(&rq->lock);
}
static inline struct rq *
this_rq_lock_irq(struct rq_flags *rf)
__acquires(rq->lock)
{
struct rq *rq;
local_irq_disable();
rq = this_rq();
rq_lock(rq, rf);
return rq;
}
#ifdef CONFIG_NUMA
enum numa_topology_type {
NUMA_DIRECT,
@ -1717,8 +1813,6 @@ static inline void sub_nr_running(struct rq *rq, unsigned count)
sched_update_tick_dependency(rq);
}
extern void update_rq_clock(struct rq *rq);
extern void activate_task(struct rq *rq, struct task_struct *p, int flags);
extern void deactivate_task(struct rq *rq, struct task_struct *p, int flags);
@ -1783,86 +1877,6 @@ unsigned long arch_scale_cpu_capacity(void __always_unused *sd, int cpu)
#endif
#endif
struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
__acquires(rq->lock);
struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
__acquires(p->pi_lock)
__acquires(rq->lock);
static inline void __task_rq_unlock(struct rq *rq, struct rq_flags *rf)
__releases(rq->lock)
{
rq_unpin_lock(rq, rf);
raw_spin_unlock(&rq->lock);
}
static inline void
task_rq_unlock(struct rq *rq, struct task_struct *p, struct rq_flags *rf)
__releases(rq->lock)
__releases(p->pi_lock)
{
rq_unpin_lock(rq, rf);
raw_spin_unlock(&rq->lock);
raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
}
static inline void
rq_lock_irqsave(struct rq *rq, struct rq_flags *rf)
__acquires(rq->lock)
{
raw_spin_lock_irqsave(&rq->lock, rf->flags);
rq_pin_lock(rq, rf);
}
static inline void
rq_lock_irq(struct rq *rq, struct rq_flags *rf)
__acquires(rq->lock)
{
raw_spin_lock_irq(&rq->lock);
rq_pin_lock(rq, rf);
}
static inline void
rq_lock(struct rq *rq, struct rq_flags *rf)
__acquires(rq->lock)
{
raw_spin_lock(&rq->lock);
rq_pin_lock(rq, rf);
}
static inline void
rq_relock(struct rq *rq, struct rq_flags *rf)
__acquires(rq->lock)
{
raw_spin_lock(&rq->lock);
rq_repin_lock(rq, rf);
}
static inline void
rq_unlock_irqrestore(struct rq *rq, struct rq_flags *rf)
__releases(rq->lock)
{
rq_unpin_lock(rq, rf);
raw_spin_unlock_irqrestore(&rq->lock, rf->flags);
}
static inline void
rq_unlock_irq(struct rq *rq, struct rq_flags *rf)
__releases(rq->lock)
{
rq_unpin_lock(rq, rf);
raw_spin_unlock_irq(&rq->lock);
}
static inline void
rq_unlock(struct rq *rq, struct rq_flags *rf)
__releases(rq->lock)
{
rq_unpin_lock(rq, rf);
raw_spin_unlock(&rq->lock);
}
#ifdef CONFIG_SMP
#ifdef CONFIG_PREEMPT

86
kernel/sched/stats.h
View file

@ -55,6 +55,92 @@ static inline void rq_sched_info_depart (struct rq *rq, unsigned long long delt
# define schedstat_val_or_zero(var) 0
#endif /* CONFIG_SCHEDSTATS */
#ifdef CONFIG_PSI
/*
* PSI tracks state that persists across sleeps, such as iowaits and
* memory stalls. As a result, it has to distinguish between sleeps,
* where a task's runnable state changes, and requeues, where a task
* and its state are being moved between CPUs and runqueues.
*/
static inline void psi_enqueue(struct task_struct *p, bool wakeup)
{
int clear = 0, set = TSK_RUNNING;
if (psi_disabled)
return;
if (!wakeup || p->sched_psi_wake_requeue) {
if (p->flags & PF_MEMSTALL)
set |= TSK_MEMSTALL;
if (p->sched_psi_wake_requeue)
p->sched_psi_wake_requeue = 0;
} else {
if (p->in_iowait)
clear |= TSK_IOWAIT;
}
psi_task_change(p, clear, set);
}
static inline void psi_dequeue(struct task_struct *p, bool sleep)
{
int clear = TSK_RUNNING, set = 0;
if (psi_disabled)
return;
if (!sleep) {
if (p->flags & PF_MEMSTALL)
clear |= TSK_MEMSTALL;
} else {
if (p->in_iowait)
set |= TSK_IOWAIT;
}
psi_task_change(p, clear, set);
}
static inline void psi_ttwu_dequeue(struct task_struct *p)
{
if (psi_disabled)
return;
/*
* Is the task being migrated during a wakeup? Make sure to
* deregister its sleep-persistent psi states from the old
* queue, and let psi_enqueue() know it has to requeue.
*/
if (unlikely(p->in_iowait || (p->flags & PF_MEMSTALL))) {
struct rq_flags rf;
struct rq *rq;
int clear = 0;
if (p->in_iowait)
clear |= TSK_IOWAIT;
if (p->flags & PF_MEMSTALL)
clear |= TSK_MEMSTALL;
rq = __task_rq_lock(p, &rf);
psi_task_change(p, clear, 0);
p->sched_psi_wake_requeue = 1;
__task_rq_unlock(rq, &rf);
}
}
static inline void psi_task_tick(struct rq *rq)
{
if (psi_disabled)
return;
if (unlikely(rq->curr->flags & PF_MEMSTALL))
psi_memstall_tick(rq->curr, cpu_of(rq));
}
#else /* CONFIG_PSI */
static inline void psi_enqueue(struct task_struct *p, bool wakeup) {}
static inline void psi_dequeue(struct task_struct *p, bool sleep) {}
static inline void psi_ttwu_dequeue(struct task_struct *p) {}
static inline void psi_task_tick(struct rq *rq) {}
#endif /* CONFIG_PSI */
#ifdef CONFIG_SCHED_INFO
static inline void sched_info_reset_dequeued(struct task_struct *t)
{