linux/drivers/md/dm-stats.c
Linus Torvalds 140dfc9299 - Significant DM thin-provisioning performance improvements to meet
performance requirements that were requested by the Gluster
   distributed filesystem.  Specifically, dm-thinp now takes care to
   aggregate IO that will be issued to the same thinp block before
   issuing IO to the underlying devices.  This really helps improve
   performance on HW RAID6 devices that have a writeback cache because it
   avoids RMW in the HW RAID controller.
 
 - Some stable fixes: fix leak in DM bufio if integrity profiles were
   enabled, use memzero_explicit in DM crypt to avoid any potential for
   information leak, and a DM cache fix to properly mark a cache block
   dirty if it was promoted to the cache via the overwrite optimization.
 
 - A few simple DM persistent data library fixes
 
 - DM cache multiqueue policy block promotion improvements.
 
 - DM cache discard improvements that take advantage of range
   (multiblock) discard support in the DM bio-prison.  This allows for
   much more efficient bulk discard processing (e.g. when mkfs.xfs
   discards the entire device).
 
 - Some small optimizations in DM core and RCU deference cleanups
 
 - DM core changes to suspend/resume code to introduce the new internal
   suspend/resume interface that the DM thin-pool target now uses to
   suspend/resume active thin devices when the thin-pool must
   suspend/resume.  This avoids forcing userspace to track all active
   thin volumes in a thin-pool when the thin-pool is suspended for the
   purposes of metadata or data space resize.
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Merge tag 'dm-3.19-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Significant DM thin-provisioning performance improvements to meet
   performance requirements that were requested by the Gluster
   distributed filesystem.

   Specifically, dm-thinp now takes care to aggregate IO that will be
   issued to the same thinp block before issuing IO to the underlying
   devices.  This really helps improve performance on HW RAID6 devices
   that have a writeback cache because it avoids RMW in the HW RAID
   controller.

 - Some stable fixes: fix leak in DM bufio if integrity profiles were
   enabled, use memzero_explicit in DM crypt to avoid any potential for
   information leak, and a DM cache fix to properly mark a cache block
   dirty if it was promoted to the cache via the overwrite optimization.

 - A few simple DM persistent data library fixes

 - DM cache multiqueue policy block promotion improvements.

 - DM cache discard improvements that take advantage of range
   (multiblock) discard support in the DM bio-prison.  This allows for
   much more efficient bulk discard processing (e.g.  when mkfs.xfs
   discards the entire device).

 - Some small optimizations in DM core and RCU deference cleanups

 - DM core changes to suspend/resume code to introduce the new internal
   suspend/resume interface that the DM thin-pool target now uses to
   suspend/resume active thin devices when the thin-pool must
   suspend/resume.

   This avoids forcing userspace to track all active thin volumes in a
   thin-pool when the thin-pool is suspended for the purposes of
   metadata or data space resize.

* tag 'dm-3.19-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (49 commits)
  dm crypt: use memzero_explicit for on-stack buffer
  dm space map metadata: fix sm_bootstrap_get_count()
  dm space map metadata: fix sm_bootstrap_get_nr_blocks()
  dm bufio: fix memleak when using a dm_buffer's inline bio
  dm cache: fix spurious cell_defer when dealing with partial block at end of device
  dm cache: dirty flag was mistakenly being cleared when promoting via overwrite
  dm cache: only use overwrite optimisation for promotion when in writeback mode
  dm cache: discard block size must be a multiple of cache block size
  dm cache: fix a harmless race when working out if a block is discarded
  dm cache: when reloading a discard bitset allow for a different discard block size
  dm cache: fix some issues with the new discard range support
  dm array: if resizing the array is a noop set the new root to the old one
  dm: use rcu_dereference_protected instead of rcu_dereference
  dm thin: fix pool_io_hints to avoid looking at max_hw_sectors
  dm thin: suspend/resume active thin devices when reloading thin-pool
  dm: enhance internal suspend and resume interface
  dm thin: do not allow thin device activation while pool is suspended
  dm: add presuspend_undo hook to target_type
  dm: return earlier from dm_blk_ioctl if target doesn't implement .ioctl
  dm thin: remove stale 'trim' message in block comment above pool_message
  ...
2014-12-08 21:10:03 -08:00

982 lines
24 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;
};
struct dm_stat_shared {
atomic_t in_flight[2];
unsigned long stamp;
struct dm_stat_percpu tmp;
};
struct dm_stat {
struct list_head list_entry;
int id;
size_t n_entries;
sector_t start;
sector_t end;
sector_t step;
const char *program_id;
const char *aux_data;
struct rcu_head rcu_head;
size_t shared_alloc_size;
size_t percpu_alloc_size;
struct dm_stat_percpu *stat_percpu[NR_CPUS];
struct dm_stat_shared stat_shared[0];
};
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);
if (is_vmalloc_addr(ptr))
vfree(ptr);
else
kfree(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], s->percpu_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, 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;
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;
if (!check_shared_memory(shared_alloc_size + num_possible_cpus() * percpu_alloc_size))
return -ENOMEM;
s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE);
if (!s)
return -ENOMEM;
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->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);
}
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;
}
/*
* 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))
goto do_sync_free;
if (is_vmalloc_addr(s)) {
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\n", s->id,
(unsigned long long)s->start,
(unsigned long long)len,
(unsigned long long)s->step,
s->program_id,
s->aux_data);
}
}
mutex_unlock(&stats->mutex);
return 1;
}
static void dm_stat_round(struct dm_stat_shared *shared, struct dm_stat_percpu *p)
{
/*
* This is racy, but so is part_round_stats_single.
*/
unsigned long now = jiffies;
unsigned in_flight_read;
unsigned in_flight_write;
unsigned long 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, bool merged,
bool end, unsigned long duration)
{
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(shared, p);
atomic_inc(&shared->in_flight[idx]);
} else {
dm_stat_round(shared, p);
atomic_dec(&shared->in_flight[idx]);
p->sectors[idx] += len;
p->ios[idx] += 1;
p->merges[idx] += merged;
p->ticks[idx] += duration;
}
#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,
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->merged, end, duration);
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, struct dm_stats_aux *stats_aux)
{
struct dm_stat *s;
sector_t end_sector;
struct dm_stats_last_position *last;
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();
list_for_each_entry_rcu(s, &stats->list, list_entry)
__dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration, 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(shared, p);
local_irq_enable();
memset(&shared->tmp, 0, sizeof(shared->tmp));
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);
}
}
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();
}
}
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(unsigned long long j)
{
unsigned long long result = 0;
unsigned mult;
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\n",
(unsigned long long)start,
(unsigned long long)step,
shared->tmp.ios[READ],
shared->tmp.merges[READ],
shared->tmp.sectors[READ],
dm_jiffies_to_msec64(shared->tmp.ticks[READ]),
shared->tmp.ios[WRITE],
shared->tmp.merges[WRITE],
shared->tmp.sectors[WRITE],
dm_jiffies_to_msec64(shared->tmp.ticks[WRITE]),
dm_stat_in_flight(shared),
dm_jiffies_to_msec64(shared->tmp.io_ticks_total),
dm_jiffies_to_msec64(shared->tmp.time_in_queue),
dm_jiffies_to_msec64(shared->tmp.io_ticks[READ]),
dm_jiffies_to_msec64(shared->tmp.io_ticks[WRITE]));
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 message_stats_create(struct mapped_device *md,
unsigned argc, char **argv,
char *result, unsigned maxlen)
{
int id;
char dummy;
unsigned long long start, end, len, step;
unsigned divisor;
const char *program_id, *aux_data;
/*
* Input format:
* <range> <step> [<program_id> [<aux_data>]]
*/
if (argc < 3 || argc > 5)
return -EINVAL;
if (!strcmp(argv[1], "-")) {
start = 0;
len = dm_get_size(md);
if (!len)
len = 1;
} else if (sscanf(argv[1], "%llu+%llu%c", &start, &len, &dummy) != 2 ||
start != (sector_t)start || len != (sector_t)len)
return -EINVAL;
end = start + len;
if (start >= end)
return -EINVAL;
if (sscanf(argv[2], "/%u%c", &divisor, &dummy) == 1) {
step = end - start;
if (do_div(step, divisor))
step++;
if (!step)
step = 1;
} else if (sscanf(argv[2], "%llu%c", &step, &dummy) != 1 ||
step != (sector_t)step || !step)
return -EINVAL;
program_id = "-";
aux_data = "-";
if (argc > 3)
program_id = argv[3];
if (argc > 4)
aux_data = argv[4];
/*
* 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))
return 1;
id = dm_stats_create(dm_get_stats(md), start, end, step, program_id, aux_data,
dm_internal_suspend_fast, dm_internal_resume_fast, md);
if (id < 0)
return id;
snprintf(result, maxlen, "%d", id);
return 1;
}
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;
if (dm_request_based(md)) {
DMWARN("Statistics are only supported for bio-based devices");
return -EOPNOTSUPP;
}
/* 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");