linuxdebug/drivers/md/dm-stats.c

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2024-07-16 15:50:57 +02:00
// SPDX-License-Identifier: GPL-2.0
#include <linux/errno.h>
#include <linux/numa.h>
#include <linux/slab.h>
#include <linux/rculist.h>
#include <linux/threads.h>
#include <linux/preempt.h>
#include <linux/irqflags.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/device-mapper.h>
#include "dm-core.h"
#include "dm-stats.h"
#define DM_MSG_PREFIX "stats"
static int dm_stat_need_rcu_barrier;
/*
* Using 64-bit values to avoid overflow (which is a
* problem that block/genhd.c's IO accounting has).
*/
struct dm_stat_percpu {
unsigned long long sectors[2];
unsigned long long ios[2];
unsigned long long merges[2];
unsigned long long ticks[2];
unsigned long long io_ticks[2];
unsigned long long io_ticks_total;
unsigned long long time_in_queue;
unsigned long long *histogram;
};
struct dm_stat_shared {
atomic_t in_flight[2];
unsigned long long stamp;
struct dm_stat_percpu tmp;
};
struct dm_stat {
struct list_head list_entry;
int id;
unsigned int stat_flags;
size_t n_entries;
sector_t start;
sector_t end;
sector_t step;
unsigned int n_histogram_entries;
unsigned long long *histogram_boundaries;
const char *program_id;
const char *aux_data;
struct rcu_head rcu_head;
size_t shared_alloc_size;
size_t percpu_alloc_size;
size_t histogram_alloc_size;
struct dm_stat_percpu *stat_percpu[NR_CPUS];
struct dm_stat_shared stat_shared[];
};
#define STAT_PRECISE_TIMESTAMPS 1
struct dm_stats_last_position {
sector_t last_sector;
unsigned int last_rw;
};
/*
* A typo on the command line could possibly make the kernel run out of memory
* and crash. To prevent the crash we account all used memory. We fail if we
* exhaust 1/4 of all memory or 1/2 of vmalloc space.
*/
#define DM_STATS_MEMORY_FACTOR 4
#define DM_STATS_VMALLOC_FACTOR 2
static DEFINE_SPINLOCK(shared_memory_lock);
static unsigned long shared_memory_amount;
static bool __check_shared_memory(size_t alloc_size)
{
size_t a;
a = shared_memory_amount + alloc_size;
if (a < shared_memory_amount)
return false;
if (a >> PAGE_SHIFT > totalram_pages() / DM_STATS_MEMORY_FACTOR)
return false;
#ifdef CONFIG_MMU
if (a > (VMALLOC_END - VMALLOC_START) / DM_STATS_VMALLOC_FACTOR)
return false;
#endif
return true;
}
static bool check_shared_memory(size_t alloc_size)
{
bool ret;
spin_lock_irq(&shared_memory_lock);
ret = __check_shared_memory(alloc_size);
spin_unlock_irq(&shared_memory_lock);
return ret;
}
static bool claim_shared_memory(size_t alloc_size)
{
spin_lock_irq(&shared_memory_lock);
if (!__check_shared_memory(alloc_size)) {
spin_unlock_irq(&shared_memory_lock);
return false;
}
shared_memory_amount += alloc_size;
spin_unlock_irq(&shared_memory_lock);
return true;
}
static void free_shared_memory(size_t alloc_size)
{
unsigned long flags;
spin_lock_irqsave(&shared_memory_lock, flags);
if (WARN_ON_ONCE(shared_memory_amount < alloc_size)) {
spin_unlock_irqrestore(&shared_memory_lock, flags);
DMCRIT("Memory usage accounting bug.");
return;
}
shared_memory_amount -= alloc_size;
spin_unlock_irqrestore(&shared_memory_lock, flags);
}
static void *dm_kvzalloc(size_t alloc_size, int node)
{
void *p;
if (!claim_shared_memory(alloc_size))
return NULL;
p = kvzalloc_node(alloc_size, GFP_KERNEL | __GFP_NOMEMALLOC, node);
if (p)
return p;
free_shared_memory(alloc_size);
return NULL;
}
static void dm_kvfree(void *ptr, size_t alloc_size)
{
if (!ptr)
return;
free_shared_memory(alloc_size);
kvfree(ptr);
}
static void dm_stat_free(struct rcu_head *head)
{
int cpu;
struct dm_stat *s = container_of(head, struct dm_stat, rcu_head);
kfree(s->histogram_boundaries);
kfree(s->program_id);
kfree(s->aux_data);
for_each_possible_cpu(cpu) {
dm_kvfree(s->stat_percpu[cpu][0].histogram, s->histogram_alloc_size);
dm_kvfree(s->stat_percpu[cpu], s->percpu_alloc_size);
}
dm_kvfree(s->stat_shared[0].tmp.histogram, s->histogram_alloc_size);
dm_kvfree(s, s->shared_alloc_size);
}
static int dm_stat_in_flight(struct dm_stat_shared *shared)
{
return atomic_read(&shared->in_flight[READ]) +
atomic_read(&shared->in_flight[WRITE]);
}
int dm_stats_init(struct dm_stats *stats)
{
int cpu;
struct dm_stats_last_position *last;
mutex_init(&stats->mutex);
INIT_LIST_HEAD(&stats->list);
stats->precise_timestamps = false;
stats->last = alloc_percpu(struct dm_stats_last_position);
if (!stats->last)
return -ENOMEM;
for_each_possible_cpu(cpu) {
last = per_cpu_ptr(stats->last, cpu);
last->last_sector = (sector_t)ULLONG_MAX;
last->last_rw = UINT_MAX;
}
return 0;
}
void dm_stats_cleanup(struct dm_stats *stats)
{
size_t ni;
struct dm_stat *s;
struct dm_stat_shared *shared;
while (!list_empty(&stats->list)) {
s = container_of(stats->list.next, struct dm_stat, list_entry);
list_del(&s->list_entry);
for (ni = 0; ni < s->n_entries; ni++) {
shared = &s->stat_shared[ni];
if (WARN_ON(dm_stat_in_flight(shared))) {
DMCRIT("leaked in-flight counter at index %lu "
"(start %llu, end %llu, step %llu): reads %d, writes %d",
(unsigned long)ni,
(unsigned long long)s->start,
(unsigned long long)s->end,
(unsigned long long)s->step,
atomic_read(&shared->in_flight[READ]),
atomic_read(&shared->in_flight[WRITE]));
}
cond_resched();
}
dm_stat_free(&s->rcu_head);
}
free_percpu(stats->last);
mutex_destroy(&stats->mutex);
}
static void dm_stats_recalc_precise_timestamps(struct dm_stats *stats)
{
struct list_head *l;
struct dm_stat *tmp_s;
bool precise_timestamps = false;
list_for_each(l, &stats->list) {
tmp_s = container_of(l, struct dm_stat, list_entry);
if (tmp_s->stat_flags & STAT_PRECISE_TIMESTAMPS) {
precise_timestamps = true;
break;
}
}
stats->precise_timestamps = precise_timestamps;
}
static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end,
sector_t step, unsigned int stat_flags,
unsigned int n_histogram_entries,
unsigned long long *histogram_boundaries,
const char *program_id, const char *aux_data,
void (*suspend_callback)(struct mapped_device *),
void (*resume_callback)(struct mapped_device *),
struct mapped_device *md)
{
struct list_head *l;
struct dm_stat *s, *tmp_s;
sector_t n_entries;
size_t ni;
size_t shared_alloc_size;
size_t percpu_alloc_size;
size_t histogram_alloc_size;
struct dm_stat_percpu *p;
int cpu;
int ret_id;
int r;
if (end < start || !step)
return -EINVAL;
n_entries = end - start;
if (dm_sector_div64(n_entries, step))
n_entries++;
if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))
return -EOVERFLOW;
shared_alloc_size = struct_size(s, stat_shared, n_entries);
if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries)
return -EOVERFLOW;
percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu);
if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries)
return -EOVERFLOW;
histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long);
if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long))
return -EOVERFLOW;
if (!check_shared_memory(shared_alloc_size + histogram_alloc_size +
num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size)))
return -ENOMEM;
s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE);
if (!s)
return -ENOMEM;
s->stat_flags = stat_flags;
s->n_entries = n_entries;
s->start = start;
s->end = end;
s->step = step;
s->shared_alloc_size = shared_alloc_size;
s->percpu_alloc_size = percpu_alloc_size;
s->histogram_alloc_size = histogram_alloc_size;
s->n_histogram_entries = n_histogram_entries;
s->histogram_boundaries = kmemdup(histogram_boundaries,
s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
if (!s->histogram_boundaries) {
r = -ENOMEM;
goto out;
}
s->program_id = kstrdup(program_id, GFP_KERNEL);
if (!s->program_id) {
r = -ENOMEM;
goto out;
}
s->aux_data = kstrdup(aux_data, GFP_KERNEL);
if (!s->aux_data) {
r = -ENOMEM;
goto out;
}
for (ni = 0; ni < n_entries; ni++) {
atomic_set(&s->stat_shared[ni].in_flight[READ], 0);
atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0);
cond_resched();
}
if (s->n_histogram_entries) {
unsigned long long *hi;
hi = dm_kvzalloc(s->histogram_alloc_size, NUMA_NO_NODE);
if (!hi) {
r = -ENOMEM;
goto out;
}
for (ni = 0; ni < n_entries; ni++) {
s->stat_shared[ni].tmp.histogram = hi;
hi += s->n_histogram_entries + 1;
cond_resched();
}
}
for_each_possible_cpu(cpu) {
p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu));
if (!p) {
r = -ENOMEM;
goto out;
}
s->stat_percpu[cpu] = p;
if (s->n_histogram_entries) {
unsigned long long *hi;
hi = dm_kvzalloc(s->histogram_alloc_size, cpu_to_node(cpu));
if (!hi) {
r = -ENOMEM;
goto out;
}
for (ni = 0; ni < n_entries; ni++) {
p[ni].histogram = hi;
hi += s->n_histogram_entries + 1;
cond_resched();
}
}
}
/*
* Suspend/resume to make sure there is no i/o in flight,
* so that newly created statistics will be exact.
*
* (note: we couldn't suspend earlier because we must not
* allocate memory while suspended)
*/
suspend_callback(md);
mutex_lock(&stats->mutex);
s->id = 0;
list_for_each(l, &stats->list) {
tmp_s = container_of(l, struct dm_stat, list_entry);
if (WARN_ON(tmp_s->id < s->id)) {
r = -EINVAL;
goto out_unlock_resume;
}
if (tmp_s->id > s->id)
break;
if (unlikely(s->id == INT_MAX)) {
r = -ENFILE;
goto out_unlock_resume;
}
s->id++;
}
ret_id = s->id;
list_add_tail_rcu(&s->list_entry, l);
dm_stats_recalc_precise_timestamps(stats);
if (!static_key_enabled(&stats_enabled.key))
static_branch_enable(&stats_enabled);
mutex_unlock(&stats->mutex);
resume_callback(md);
return ret_id;
out_unlock_resume:
mutex_unlock(&stats->mutex);
resume_callback(md);
out:
dm_stat_free(&s->rcu_head);
return r;
}
static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id)
{
struct dm_stat *s;
list_for_each_entry(s, &stats->list, list_entry) {
if (s->id > id)
break;
if (s->id == id)
return s;
}
return NULL;
}
static int dm_stats_delete(struct dm_stats *stats, int id)
{
struct dm_stat *s;
int cpu;
mutex_lock(&stats->mutex);
s = __dm_stats_find(stats, id);
if (!s) {
mutex_unlock(&stats->mutex);
return -ENOENT;
}
list_del_rcu(&s->list_entry);
dm_stats_recalc_precise_timestamps(stats);
mutex_unlock(&stats->mutex);
/*
* vfree can't be called from RCU callback
*/
for_each_possible_cpu(cpu)
if (is_vmalloc_addr(s->stat_percpu) ||
is_vmalloc_addr(s->stat_percpu[cpu][0].histogram))
goto do_sync_free;
if (is_vmalloc_addr(s) ||
is_vmalloc_addr(s->stat_shared[0].tmp.histogram)) {
do_sync_free:
synchronize_rcu_expedited();
dm_stat_free(&s->rcu_head);
} else {
WRITE_ONCE(dm_stat_need_rcu_barrier, 1);
call_rcu(&s->rcu_head, dm_stat_free);
}
return 0;
}
static int dm_stats_list(struct dm_stats *stats, const char *program,
char *result, unsigned int maxlen)
{
struct dm_stat *s;
sector_t len;
unsigned int sz = 0;
/*
* Output format:
* <region_id>: <start_sector>+<length> <step> <program_id> <aux_data>
*/
mutex_lock(&stats->mutex);
list_for_each_entry(s, &stats->list, list_entry) {
if (!program || !strcmp(program, s->program_id)) {
len = s->end - s->start;
DMEMIT("%d: %llu+%llu %llu %s %s", s->id,
(unsigned long long)s->start,
(unsigned long long)len,
(unsigned long long)s->step,
s->program_id,
s->aux_data);
if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
DMEMIT(" precise_timestamps");
if (s->n_histogram_entries) {
unsigned int i;
DMEMIT(" histogram:");
for (i = 0; i < s->n_histogram_entries; i++) {
if (i)
DMEMIT(",");
DMEMIT("%llu", s->histogram_boundaries[i]);
}
}
DMEMIT("\n");
}
cond_resched();
}
mutex_unlock(&stats->mutex);
return 1;
}
static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared,
struct dm_stat_percpu *p)
{
/*
* This is racy, but so is part_round_stats_single.
*/
unsigned long long now, difference;
unsigned int in_flight_read, in_flight_write;
if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)))
now = jiffies;
else
now = ktime_to_ns(ktime_get());
difference = now - shared->stamp;
if (!difference)
return;
in_flight_read = (unsigned int)atomic_read(&shared->in_flight[READ]);
in_flight_write = (unsigned int)atomic_read(&shared->in_flight[WRITE]);
if (in_flight_read)
p->io_ticks[READ] += difference;
if (in_flight_write)
p->io_ticks[WRITE] += difference;
if (in_flight_read + in_flight_write) {
p->io_ticks_total += difference;
p->time_in_queue += (in_flight_read + in_flight_write) * difference;
}
shared->stamp = now;
}
static void dm_stat_for_entry(struct dm_stat *s, size_t entry,
int idx, sector_t len,
struct dm_stats_aux *stats_aux, bool end,
unsigned long duration_jiffies)
{
struct dm_stat_shared *shared = &s->stat_shared[entry];
struct dm_stat_percpu *p;
/*
* For strict correctness we should use local_irq_save/restore
* instead of preempt_disable/enable.
*
* preempt_disable/enable is racy if the driver finishes bios
* from non-interrupt context as well as from interrupt context
* or from more different interrupts.
*
* On 64-bit architectures the race only results in not counting some
* events, so it is acceptable. On 32-bit architectures the race could
* cause the counter going off by 2^32, so we need to do proper locking
* there.
*
* part_stat_lock()/part_stat_unlock() have this race too.
*/
#if BITS_PER_LONG == 32
unsigned long flags;
local_irq_save(flags);
#else
preempt_disable();
#endif
p = &s->stat_percpu[smp_processor_id()][entry];
if (!end) {
dm_stat_round(s, shared, p);
atomic_inc(&shared->in_flight[idx]);
} else {
unsigned long long duration;
dm_stat_round(s, shared, p);
atomic_dec(&shared->in_flight[idx]);
p->sectors[idx] += len;
p->ios[idx] += 1;
p->merges[idx] += stats_aux->merged;
if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) {
p->ticks[idx] += duration_jiffies;
duration = jiffies_to_msecs(duration_jiffies);
} else {
p->ticks[idx] += stats_aux->duration_ns;
duration = stats_aux->duration_ns;
}
if (s->n_histogram_entries) {
unsigned int lo = 0, hi = s->n_histogram_entries + 1;
while (lo + 1 < hi) {
unsigned int mid = (lo + hi) / 2;
if (s->histogram_boundaries[mid - 1] > duration) {
hi = mid;
} else {
lo = mid;
}
}
p->histogram[lo]++;
}
}
#if BITS_PER_LONG == 32
local_irq_restore(flags);
#else
preempt_enable();
#endif
}
static void __dm_stat_bio(struct dm_stat *s, int bi_rw,
sector_t bi_sector, sector_t end_sector,
bool end, unsigned long duration_jiffies,
struct dm_stats_aux *stats_aux)
{
sector_t rel_sector, offset, todo, fragment_len;
size_t entry;
if (end_sector <= s->start || bi_sector >= s->end)
return;
if (unlikely(bi_sector < s->start)) {
rel_sector = 0;
todo = end_sector - s->start;
} else {
rel_sector = bi_sector - s->start;
todo = end_sector - bi_sector;
}
if (unlikely(end_sector > s->end))
todo -= (end_sector - s->end);
offset = dm_sector_div64(rel_sector, s->step);
entry = rel_sector;
do {
if (WARN_ON_ONCE(entry >= s->n_entries)) {
DMCRIT("Invalid area access in region id %d", s->id);
return;
}
fragment_len = todo;
if (fragment_len > s->step - offset)
fragment_len = s->step - offset;
dm_stat_for_entry(s, entry, bi_rw, fragment_len,
stats_aux, end, duration_jiffies);
todo -= fragment_len;
entry++;
offset = 0;
} while (unlikely(todo != 0));
}
void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
sector_t bi_sector, unsigned int bi_sectors, bool end,
unsigned long start_time,
struct dm_stats_aux *stats_aux)
{
struct dm_stat *s;
sector_t end_sector;
struct dm_stats_last_position *last;
bool got_precise_time;
unsigned long duration_jiffies = 0;
if (unlikely(!bi_sectors))
return;
end_sector = bi_sector + bi_sectors;
if (!end) {
/*
* A race condition can at worst result in the merged flag being
* misrepresented, so we don't have to disable preemption here.
*/
last = raw_cpu_ptr(stats->last);
stats_aux->merged =
(bi_sector == (READ_ONCE(last->last_sector) &&
((bi_rw == WRITE) ==
(READ_ONCE(last->last_rw) == WRITE))
));
WRITE_ONCE(last->last_sector, end_sector);
WRITE_ONCE(last->last_rw, bi_rw);
} else
duration_jiffies = jiffies - start_time;
rcu_read_lock();
got_precise_time = false;
list_for_each_entry_rcu(s, &stats->list, list_entry) {
if (s->stat_flags & STAT_PRECISE_TIMESTAMPS && !got_precise_time) {
/* start (!end) duration_ns is set by DM core's alloc_io() */
if (end)
stats_aux->duration_ns = ktime_to_ns(ktime_get()) - stats_aux->duration_ns;
got_precise_time = true;
}
__dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux);
}
rcu_read_unlock();
}
static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared,
struct dm_stat *s, size_t x)
{
int cpu;
struct dm_stat_percpu *p;
local_irq_disable();
p = &s->stat_percpu[smp_processor_id()][x];
dm_stat_round(s, shared, p);
local_irq_enable();
shared->tmp.sectors[READ] = 0;
shared->tmp.sectors[WRITE] = 0;
shared->tmp.ios[READ] = 0;
shared->tmp.ios[WRITE] = 0;
shared->tmp.merges[READ] = 0;
shared->tmp.merges[WRITE] = 0;
shared->tmp.ticks[READ] = 0;
shared->tmp.ticks[WRITE] = 0;
shared->tmp.io_ticks[READ] = 0;
shared->tmp.io_ticks[WRITE] = 0;
shared->tmp.io_ticks_total = 0;
shared->tmp.time_in_queue = 0;
if (s->n_histogram_entries)
memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long));
for_each_possible_cpu(cpu) {
p = &s->stat_percpu[cpu][x];
shared->tmp.sectors[READ] += READ_ONCE(p->sectors[READ]);
shared->tmp.sectors[WRITE] += READ_ONCE(p->sectors[WRITE]);
shared->tmp.ios[READ] += READ_ONCE(p->ios[READ]);
shared->tmp.ios[WRITE] += READ_ONCE(p->ios[WRITE]);
shared->tmp.merges[READ] += READ_ONCE(p->merges[READ]);
shared->tmp.merges[WRITE] += READ_ONCE(p->merges[WRITE]);
shared->tmp.ticks[READ] += READ_ONCE(p->ticks[READ]);
shared->tmp.ticks[WRITE] += READ_ONCE(p->ticks[WRITE]);
shared->tmp.io_ticks[READ] += READ_ONCE(p->io_ticks[READ]);
shared->tmp.io_ticks[WRITE] += READ_ONCE(p->io_ticks[WRITE]);
shared->tmp.io_ticks_total += READ_ONCE(p->io_ticks_total);
shared->tmp.time_in_queue += READ_ONCE(p->time_in_queue);
if (s->n_histogram_entries) {
unsigned int i;
for (i = 0; i < s->n_histogram_entries + 1; i++)
shared->tmp.histogram[i] += READ_ONCE(p->histogram[i]);
}
}
}
static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end,
bool init_tmp_percpu_totals)
{
size_t x;
struct dm_stat_shared *shared;
struct dm_stat_percpu *p;
for (x = idx_start; x < idx_end; x++) {
shared = &s->stat_shared[x];
if (init_tmp_percpu_totals)
__dm_stat_init_temporary_percpu_totals(shared, s, x);
local_irq_disable();
p = &s->stat_percpu[smp_processor_id()][x];
p->sectors[READ] -= shared->tmp.sectors[READ];
p->sectors[WRITE] -= shared->tmp.sectors[WRITE];
p->ios[READ] -= shared->tmp.ios[READ];
p->ios[WRITE] -= shared->tmp.ios[WRITE];
p->merges[READ] -= shared->tmp.merges[READ];
p->merges[WRITE] -= shared->tmp.merges[WRITE];
p->ticks[READ] -= shared->tmp.ticks[READ];
p->ticks[WRITE] -= shared->tmp.ticks[WRITE];
p->io_ticks[READ] -= shared->tmp.io_ticks[READ];
p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE];
p->io_ticks_total -= shared->tmp.io_ticks_total;
p->time_in_queue -= shared->tmp.time_in_queue;
local_irq_enable();
if (s->n_histogram_entries) {
unsigned int i;
for (i = 0; i < s->n_histogram_entries + 1; i++) {
local_irq_disable();
p = &s->stat_percpu[smp_processor_id()][x];
p->histogram[i] -= shared->tmp.histogram[i];
local_irq_enable();
}
}
cond_resched();
}
}
static int dm_stats_clear(struct dm_stats *stats, int id)
{
struct dm_stat *s;
mutex_lock(&stats->mutex);
s = __dm_stats_find(stats, id);
if (!s) {
mutex_unlock(&stats->mutex);
return -ENOENT;
}
__dm_stat_clear(s, 0, s->n_entries, true);
mutex_unlock(&stats->mutex);
return 1;
}
/*
* This is like jiffies_to_msec, but works for 64-bit values.
*/
static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j)
{
unsigned long long result;
unsigned int mult;
if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
return j;
result = 0;
if (j)
result = jiffies_to_msecs(j & 0x3fffff);
if (j >= 1 << 22) {
mult = jiffies_to_msecs(1 << 22);
result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs((j >> 22) & 0x3fffff);
}
if (j >= 1ULL << 44)
result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j >> 44);
return result;
}
static int dm_stats_print(struct dm_stats *stats, int id,
size_t idx_start, size_t idx_len,
bool clear, char *result, unsigned int maxlen)
{
unsigned int sz = 0;
struct dm_stat *s;
size_t x;
sector_t start, end, step;
size_t idx_end;
struct dm_stat_shared *shared;
/*
* Output format:
* <start_sector>+<length> counters
*/
mutex_lock(&stats->mutex);
s = __dm_stats_find(stats, id);
if (!s) {
mutex_unlock(&stats->mutex);
return -ENOENT;
}
idx_end = idx_start + idx_len;
if (idx_end < idx_start ||
idx_end > s->n_entries)
idx_end = s->n_entries;
if (idx_start > idx_end)
idx_start = idx_end;
step = s->step;
start = s->start + (step * idx_start);
for (x = idx_start; x < idx_end; x++, start = end) {
shared = &s->stat_shared[x];
end = start + step;
if (unlikely(end > s->end))
end = s->end;
__dm_stat_init_temporary_percpu_totals(shared, s, x);
DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu",
(unsigned long long)start,
(unsigned long long)step,
shared->tmp.ios[READ],
shared->tmp.merges[READ],
shared->tmp.sectors[READ],
dm_jiffies_to_msec64(s, shared->tmp.ticks[READ]),
shared->tmp.ios[WRITE],
shared->tmp.merges[WRITE],
shared->tmp.sectors[WRITE],
dm_jiffies_to_msec64(s, shared->tmp.ticks[WRITE]),
dm_stat_in_flight(shared),
dm_jiffies_to_msec64(s, shared->tmp.io_ticks_total),
dm_jiffies_to_msec64(s, shared->tmp.time_in_queue),
dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]),
dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE]));
if (s->n_histogram_entries) {
unsigned int i;
for (i = 0; i < s->n_histogram_entries + 1; i++) {
DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]);
}
}
DMEMIT("\n");
if (unlikely(sz + 1 >= maxlen))
goto buffer_overflow;
cond_resched();
}
if (clear)
__dm_stat_clear(s, idx_start, idx_end, false);
buffer_overflow:
mutex_unlock(&stats->mutex);
return 1;
}
static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data)
{
struct dm_stat *s;
const char *new_aux_data;
mutex_lock(&stats->mutex);
s = __dm_stats_find(stats, id);
if (!s) {
mutex_unlock(&stats->mutex);
return -ENOENT;
}
new_aux_data = kstrdup(aux_data, GFP_KERNEL);
if (!new_aux_data) {
mutex_unlock(&stats->mutex);
return -ENOMEM;
}
kfree(s->aux_data);
s->aux_data = new_aux_data;
mutex_unlock(&stats->mutex);
return 0;
}
static int parse_histogram(const char *h, unsigned int *n_histogram_entries,
unsigned long long **histogram_boundaries)
{
const char *q;
unsigned int n;
unsigned long long last;
*n_histogram_entries = 1;
for (q = h; *q; q++)
if (*q == ',')
(*n_histogram_entries)++;
*histogram_boundaries = kmalloc_array(*n_histogram_entries,
sizeof(unsigned long long),
GFP_KERNEL);
if (!*histogram_boundaries)
return -ENOMEM;
n = 0;
last = 0;
while (1) {
unsigned long long hi;
int s;
char ch;
s = sscanf(h, "%llu%c", &hi, &ch);
if (!s || (s == 2 && ch != ','))
return -EINVAL;
if (hi <= last)
return -EINVAL;
last = hi;
(*histogram_boundaries)[n] = hi;
if (s == 1)
return 0;
h = strchr(h, ',') + 1;
n++;
}
}
static int message_stats_create(struct mapped_device *md,
unsigned int argc, char **argv,
char *result, unsigned int maxlen)
{
int r;
int id;
char dummy;
unsigned long long start, end, len, step;
unsigned int divisor;
const char *program_id, *aux_data;
unsigned int stat_flags = 0;
unsigned int n_histogram_entries = 0;
unsigned long long *histogram_boundaries = NULL;
struct dm_arg_set as, as_backup;
const char *a;
unsigned int feature_args;
/*
* Input format:
* <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]]
*/
if (argc < 3)
goto ret_einval;
as.argc = argc;
as.argv = argv;
dm_consume_args(&as, 1);
a = dm_shift_arg(&as);
if (!strcmp(a, "-")) {
start = 0;
len = dm_get_size(md);
if (!len)
len = 1;
} else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 ||
start != (sector_t)start || len != (sector_t)len)
goto ret_einval;
end = start + len;
if (start >= end)
goto ret_einval;
a = dm_shift_arg(&as);
if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) {
if (!divisor)
return -EINVAL;
step = end - start;
if (do_div(step, divisor))
step++;
if (!step)
step = 1;
} else if (sscanf(a, "%llu%c", &step, &dummy) != 1 ||
step != (sector_t)step || !step)
goto ret_einval;
as_backup = as;
a = dm_shift_arg(&as);
if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) {
while (feature_args--) {
a = dm_shift_arg(&as);
if (!a)
goto ret_einval;
if (!strcasecmp(a, "precise_timestamps"))
stat_flags |= STAT_PRECISE_TIMESTAMPS;
else if (!strncasecmp(a, "histogram:", 10)) {
if (n_histogram_entries)
goto ret_einval;
if ((r = parse_histogram(a + 10, &n_histogram_entries, &histogram_boundaries)))
goto ret;
} else
goto ret_einval;
}
} else {
as = as_backup;
}
program_id = "-";
aux_data = "-";
a = dm_shift_arg(&as);
if (a)
program_id = a;
a = dm_shift_arg(&as);
if (a)
aux_data = a;
if (as.argc)
goto ret_einval;
/*
* If a buffer overflow happens after we created the region,
* it's too late (the userspace would retry with a larger
* buffer, but the region id that caused the overflow is already
* leaked). So we must detect buffer overflow in advance.
*/
snprintf(result, maxlen, "%d", INT_MAX);
if (dm_message_test_buffer_overflow(result, maxlen)) {
r = 1;
goto ret;
}
id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags,
n_histogram_entries, histogram_boundaries, program_id, aux_data,
dm_internal_suspend_fast, dm_internal_resume_fast, md);
if (id < 0) {
r = id;
goto ret;
}
snprintf(result, maxlen, "%d", id);
r = 1;
goto ret;
ret_einval:
r = -EINVAL;
ret:
kfree(histogram_boundaries);
return r;
}
static int message_stats_delete(struct mapped_device *md,
unsigned int argc, char **argv)
{
int id;
char dummy;
if (argc != 2)
return -EINVAL;
if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
return -EINVAL;
return dm_stats_delete(dm_get_stats(md), id);
}
static int message_stats_clear(struct mapped_device *md,
unsigned int argc, char **argv)
{
int id;
char dummy;
if (argc != 2)
return -EINVAL;
if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
return -EINVAL;
return dm_stats_clear(dm_get_stats(md), id);
}
static int message_stats_list(struct mapped_device *md,
unsigned int argc, char **argv,
char *result, unsigned int maxlen)
{
int r;
const char *program = NULL;
if (argc < 1 || argc > 2)
return -EINVAL;
if (argc > 1) {
program = kstrdup(argv[1], GFP_KERNEL);
if (!program)
return -ENOMEM;
}
r = dm_stats_list(dm_get_stats(md), program, result, maxlen);
kfree(program);
return r;
}
static int message_stats_print(struct mapped_device *md,
unsigned int argc, char **argv, bool clear,
char *result, unsigned int maxlen)
{
int id;
char dummy;
unsigned long idx_start = 0, idx_len = ULONG_MAX;
if (argc != 2 && argc != 4)
return -EINVAL;
if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
return -EINVAL;
if (argc > 3) {
if (strcmp(argv[2], "-") &&
sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1)
return -EINVAL;
if (strcmp(argv[3], "-") &&
sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1)
return -EINVAL;
}
return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear,
result, maxlen);
}
static int message_stats_set_aux(struct mapped_device *md,
unsigned int argc, char **argv)
{
int id;
char dummy;
if (argc != 3)
return -EINVAL;
if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0)
return -EINVAL;
return dm_stats_set_aux(dm_get_stats(md), id, argv[2]);
}
int dm_stats_message(struct mapped_device *md, unsigned int argc, char **argv,
char *result, unsigned int maxlen)
{
int r;
/* All messages here must start with '@' */
if (!strcasecmp(argv[0], "@stats_create"))
r = message_stats_create(md, argc, argv, result, maxlen);
else if (!strcasecmp(argv[0], "@stats_delete"))
r = message_stats_delete(md, argc, argv);
else if (!strcasecmp(argv[0], "@stats_clear"))
r = message_stats_clear(md, argc, argv);
else if (!strcasecmp(argv[0], "@stats_list"))
r = message_stats_list(md, argc, argv, result, maxlen);
else if (!strcasecmp(argv[0], "@stats_print"))
r = message_stats_print(md, argc, argv, false, result, maxlen);
else if (!strcasecmp(argv[0], "@stats_print_clear"))
r = message_stats_print(md, argc, argv, true, result, maxlen);
else if (!strcasecmp(argv[0], "@stats_set_aux"))
r = message_stats_set_aux(md, argc, argv);
else
return 2; /* this wasn't a stats message */
if (r == -EINVAL)
DMCRIT("Invalid parameters for message %s", argv[0]);
return r;
}
int __init dm_statistics_init(void)
{
shared_memory_amount = 0;
dm_stat_need_rcu_barrier = 0;
return 0;
}
void dm_statistics_exit(void)
{
if (dm_stat_need_rcu_barrier)
rcu_barrier();
if (WARN_ON(shared_memory_amount))
DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount);
}
module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, S_IRUGO);
MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics");