kernel-ark/drivers/md/dm-stats.c
Mikulas Patocka bd49784fd1 dm stats: report precise_timestamps and histogram in @stats_list output
If the user selected the precise_timestamps or histogram options, report
it in the @stats_list message output.

If the user didn't select these options, no extra tokens are reported,
thus it is backward compatible with old software that doesn't know about
precise timestamps and histogram.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 4.2
2015-08-18 17:20:03 -04:00

1211 lines
29 KiB
C

#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.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 stat_flags;
size_t n_entries;
sector_t start;
sector_t end;
sector_t step;
unsigned 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[0];
};
#define STAT_PRECISE_TIMESTAMPS 1
struct dm_stats_last_position {
sector_t last_sector;
unsigned 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;
if (alloc_size <= KMALLOC_MAX_SIZE) {
p = kzalloc_node(alloc_size, GFP_KERNEL | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN, node);
if (p)
return p;
}
p = vzalloc_node(alloc_size, 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->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]);
}
void 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->last = alloc_percpu(struct dm_stats_last_position);
for_each_possible_cpu(cpu) {
last = per_cpu_ptr(stats->last, cpu);
last->last_sector = (sector_t)ULLONG_MAX;
last->last_rw = UINT_MAX;
}
}
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]));
}
}
dm_stat_free(&s->rcu_head);
}
free_percpu(stats->last);
}
static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end,
sector_t step, unsigned stat_flags,
unsigned 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 = sizeof(struct dm_stat) + (size_t)n_entries * sizeof(struct dm_stat_shared);
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);
}
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;
}
}
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;
}
}
}
/*
* 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);
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);
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 {
ACCESS_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 maxlen)
{
struct dm_stat *s;
sector_t len;
unsigned 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 i;
DMEMIT(" histogram:");
for (i = 0; i < s->n_histogram_entries; i++) {
if (i)
DMEMIT(",");
DMEMIT("%llu", s->histogram_boundaries[i]);
}
}
DMEMIT("\n");
}
}
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 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)atomic_read(&shared->in_flight[READ]);
in_flight_write = (unsigned)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,
unsigned long bi_rw, sector_t len,
struct dm_stats_aux *stats_aux, bool end,
unsigned long duration_jiffies)
{
unsigned long idx = bi_rw & REQ_WRITE;
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 lo = 0, hi = s->n_histogram_entries + 1;
while (lo + 1 < hi) {
unsigned 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, unsigned long 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 bi_sectors, bool end,
unsigned long duration_jiffies,
struct dm_stats_aux *stats_aux)
{
struct dm_stat *s;
sector_t end_sector;
struct dm_stats_last_position *last;
bool got_precise_time;
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 == (ACCESS_ONCE(last->last_sector) &&
((bi_rw & (REQ_WRITE | REQ_DISCARD)) ==
(ACCESS_ONCE(last->last_rw) & (REQ_WRITE | REQ_DISCARD)))
));
ACCESS_ONCE(last->last_sector) = end_sector;
ACCESS_ONCE(last->last_rw) = bi_rw;
}
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) {
if (!end)
stats_aux->duration_ns = ktime_to_ns(ktime_get());
else
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] += ACCESS_ONCE(p->sectors[READ]);
shared->tmp.sectors[WRITE] += ACCESS_ONCE(p->sectors[WRITE]);
shared->tmp.ios[READ] += ACCESS_ONCE(p->ios[READ]);
shared->tmp.ios[WRITE] += ACCESS_ONCE(p->ios[WRITE]);
shared->tmp.merges[READ] += ACCESS_ONCE(p->merges[READ]);
shared->tmp.merges[WRITE] += ACCESS_ONCE(p->merges[WRITE]);
shared->tmp.ticks[READ] += ACCESS_ONCE(p->ticks[READ]);
shared->tmp.ticks[WRITE] += ACCESS_ONCE(p->ticks[WRITE]);
shared->tmp.io_ticks[READ] += ACCESS_ONCE(p->io_ticks[READ]);
shared->tmp.io_ticks[WRITE] += ACCESS_ONCE(p->io_ticks[WRITE]);
shared->tmp.io_ticks_total += ACCESS_ONCE(p->io_ticks_total);
shared->tmp.time_in_queue += ACCESS_ONCE(p->time_in_queue);
if (s->n_histogram_entries) {
unsigned i;
for (i = 0; i < s->n_histogram_entries + 1; i++)
shared->tmp.histogram[i] += ACCESS_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 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();
}
}
}
}
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 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 maxlen)
{
unsigned 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 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;
}
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 *n_histogram_entries,
unsigned long long **histogram_boundaries)
{
const char *q;
unsigned n;
unsigned long long last;
*n_histogram_entries = 1;
for (q = h; *q; q++)
if (*q == ',')
(*n_histogram_entries)++;
*histogram_boundaries = kmalloc(*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 argc, char **argv,
char *result, unsigned maxlen)
{
int r;
int id;
char dummy;
unsigned long long start, end, len, step;
unsigned divisor;
const char *program_id, *aux_data;
unsigned stat_flags = 0;
unsigned n_histogram_entries = 0;
unsigned long long *histogram_boundaries = NULL;
struct dm_arg_set as, as_backup;
const char *a;
unsigned 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 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 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 argc, char **argv,
char *result, unsigned 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 argc, char **argv, bool clear,
char *result, unsigned 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 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 argc, char **argv,
char *result, unsigned 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)
DMWARN("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");