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![Mike Snitzer](/assets/img/avatar_default.png)
dm_stats_account_io()'s STAT_PRECISE_TIMESTAMPS support doesn't handle the fact that with commitb879f915bc
("dm: properly fix redundant bio-based IO accounting") io->start_time _may_ be in the past (meaning the start_io_acct() was deferred until later). Add a new dm_stats_recalc_precise_timestamps() helper that will set/clear a new 'precise_timestamps' flag in the dm_stats struct based on whether any configured stats enable STAT_PRECISE_TIMESTAMPS. And update DM core's alloc_io() to use dm_stats_record_start() to set stats_aux.duration_ns if stats->precise_timestamps is true. Also, remove unused 'last_sector' and 'last_rw' members from the dm_stats struct. Fixes:b879f915bc
("dm: properly fix redundant bio-based IO accounting") Cc: stable@vger.kernel.org Co-developed-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
1233 lines
30 KiB
C
1233 lines
30 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/errno.h>
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#include <linux/numa.h>
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#include <linux/slab.h>
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#include <linux/rculist.h>
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#include <linux/threads.h>
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#include <linux/preempt.h>
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#include <linux/irqflags.h>
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#include <linux/vmalloc.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/device-mapper.h>
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#include "dm-core.h"
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#include "dm-stats.h"
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#define DM_MSG_PREFIX "stats"
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static int dm_stat_need_rcu_barrier;
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/*
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* Using 64-bit values to avoid overflow (which is a
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* problem that block/genhd.c's IO accounting has).
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*/
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struct dm_stat_percpu {
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unsigned long long sectors[2];
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unsigned long long ios[2];
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unsigned long long merges[2];
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unsigned long long ticks[2];
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unsigned long long io_ticks[2];
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unsigned long long io_ticks_total;
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unsigned long long time_in_queue;
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unsigned long long *histogram;
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};
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struct dm_stat_shared {
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atomic_t in_flight[2];
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unsigned long long stamp;
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struct dm_stat_percpu tmp;
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};
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struct dm_stat {
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struct list_head list_entry;
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int id;
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unsigned stat_flags;
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size_t n_entries;
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sector_t start;
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sector_t end;
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sector_t step;
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unsigned n_histogram_entries;
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unsigned long long *histogram_boundaries;
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const char *program_id;
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const char *aux_data;
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struct rcu_head rcu_head;
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size_t shared_alloc_size;
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size_t percpu_alloc_size;
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size_t histogram_alloc_size;
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struct dm_stat_percpu *stat_percpu[NR_CPUS];
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struct dm_stat_shared stat_shared[];
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};
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#define STAT_PRECISE_TIMESTAMPS 1
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struct dm_stats_last_position {
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sector_t last_sector;
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unsigned last_rw;
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};
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/*
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* A typo on the command line could possibly make the kernel run out of memory
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* and crash. To prevent the crash we account all used memory. We fail if we
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* exhaust 1/4 of all memory or 1/2 of vmalloc space.
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*/
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#define DM_STATS_MEMORY_FACTOR 4
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#define DM_STATS_VMALLOC_FACTOR 2
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static DEFINE_SPINLOCK(shared_memory_lock);
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static unsigned long shared_memory_amount;
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static bool __check_shared_memory(size_t alloc_size)
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{
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size_t a;
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a = shared_memory_amount + alloc_size;
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if (a < shared_memory_amount)
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return false;
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if (a >> PAGE_SHIFT > totalram_pages() / DM_STATS_MEMORY_FACTOR)
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return false;
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#ifdef CONFIG_MMU
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if (a > (VMALLOC_END - VMALLOC_START) / DM_STATS_VMALLOC_FACTOR)
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return false;
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#endif
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return true;
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}
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static bool check_shared_memory(size_t alloc_size)
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{
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bool ret;
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spin_lock_irq(&shared_memory_lock);
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ret = __check_shared_memory(alloc_size);
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spin_unlock_irq(&shared_memory_lock);
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return ret;
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}
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static bool claim_shared_memory(size_t alloc_size)
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{
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spin_lock_irq(&shared_memory_lock);
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if (!__check_shared_memory(alloc_size)) {
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spin_unlock_irq(&shared_memory_lock);
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return false;
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}
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shared_memory_amount += alloc_size;
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spin_unlock_irq(&shared_memory_lock);
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return true;
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}
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static void free_shared_memory(size_t alloc_size)
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{
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unsigned long flags;
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spin_lock_irqsave(&shared_memory_lock, flags);
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if (WARN_ON_ONCE(shared_memory_amount < alloc_size)) {
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spin_unlock_irqrestore(&shared_memory_lock, flags);
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DMCRIT("Memory usage accounting bug.");
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return;
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}
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shared_memory_amount -= alloc_size;
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spin_unlock_irqrestore(&shared_memory_lock, flags);
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}
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static void *dm_kvzalloc(size_t alloc_size, int node)
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{
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void *p;
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if (!claim_shared_memory(alloc_size))
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return NULL;
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p = kvzalloc_node(alloc_size, GFP_KERNEL | __GFP_NOMEMALLOC, node);
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if (p)
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return p;
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free_shared_memory(alloc_size);
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return NULL;
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}
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static void dm_kvfree(void *ptr, size_t alloc_size)
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{
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if (!ptr)
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return;
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free_shared_memory(alloc_size);
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kvfree(ptr);
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}
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static void dm_stat_free(struct rcu_head *head)
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{
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int cpu;
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struct dm_stat *s = container_of(head, struct dm_stat, rcu_head);
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kfree(s->histogram_boundaries);
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kfree(s->program_id);
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kfree(s->aux_data);
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for_each_possible_cpu(cpu) {
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dm_kvfree(s->stat_percpu[cpu][0].histogram, s->histogram_alloc_size);
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dm_kvfree(s->stat_percpu[cpu], s->percpu_alloc_size);
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}
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dm_kvfree(s->stat_shared[0].tmp.histogram, s->histogram_alloc_size);
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dm_kvfree(s, s->shared_alloc_size);
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}
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static int dm_stat_in_flight(struct dm_stat_shared *shared)
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{
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return atomic_read(&shared->in_flight[READ]) +
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atomic_read(&shared->in_flight[WRITE]);
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}
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void dm_stats_init(struct dm_stats *stats)
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{
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int cpu;
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struct dm_stats_last_position *last;
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mutex_init(&stats->mutex);
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INIT_LIST_HEAD(&stats->list);
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stats->precise_timestamps = false;
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stats->last = alloc_percpu(struct dm_stats_last_position);
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for_each_possible_cpu(cpu) {
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last = per_cpu_ptr(stats->last, cpu);
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last->last_sector = (sector_t)ULLONG_MAX;
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last->last_rw = UINT_MAX;
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}
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}
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void dm_stats_cleanup(struct dm_stats *stats)
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{
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size_t ni;
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struct dm_stat *s;
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struct dm_stat_shared *shared;
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while (!list_empty(&stats->list)) {
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s = container_of(stats->list.next, struct dm_stat, list_entry);
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list_del(&s->list_entry);
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for (ni = 0; ni < s->n_entries; ni++) {
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shared = &s->stat_shared[ni];
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if (WARN_ON(dm_stat_in_flight(shared))) {
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DMCRIT("leaked in-flight counter at index %lu "
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"(start %llu, end %llu, step %llu): reads %d, writes %d",
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(unsigned long)ni,
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(unsigned long long)s->start,
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(unsigned long long)s->end,
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(unsigned long long)s->step,
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atomic_read(&shared->in_flight[READ]),
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atomic_read(&shared->in_flight[WRITE]));
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}
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}
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dm_stat_free(&s->rcu_head);
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}
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free_percpu(stats->last);
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mutex_destroy(&stats->mutex);
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}
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static void dm_stats_recalc_precise_timestamps(struct dm_stats *stats)
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{
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struct list_head *l;
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struct dm_stat *tmp_s;
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bool precise_timestamps = false;
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list_for_each(l, &stats->list) {
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tmp_s = container_of(l, struct dm_stat, list_entry);
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if (tmp_s->stat_flags & STAT_PRECISE_TIMESTAMPS) {
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precise_timestamps = true;
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break;
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}
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}
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stats->precise_timestamps = precise_timestamps;
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}
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static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end,
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sector_t step, unsigned stat_flags,
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unsigned n_histogram_entries,
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unsigned long long *histogram_boundaries,
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const char *program_id, const char *aux_data,
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void (*suspend_callback)(struct mapped_device *),
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void (*resume_callback)(struct mapped_device *),
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struct mapped_device *md)
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{
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struct list_head *l;
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struct dm_stat *s, *tmp_s;
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sector_t n_entries;
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size_t ni;
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size_t shared_alloc_size;
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size_t percpu_alloc_size;
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size_t histogram_alloc_size;
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struct dm_stat_percpu *p;
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int cpu;
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int ret_id;
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int r;
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if (end < start || !step)
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return -EINVAL;
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n_entries = end - start;
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if (dm_sector_div64(n_entries, step))
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n_entries++;
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if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1))
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return -EOVERFLOW;
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shared_alloc_size = struct_size(s, stat_shared, n_entries);
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if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries)
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return -EOVERFLOW;
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percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu);
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if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries)
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return -EOVERFLOW;
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histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long);
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if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long))
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return -EOVERFLOW;
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if (!check_shared_memory(shared_alloc_size + histogram_alloc_size +
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num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size)))
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return -ENOMEM;
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s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE);
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if (!s)
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return -ENOMEM;
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s->stat_flags = stat_flags;
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s->n_entries = n_entries;
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s->start = start;
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s->end = end;
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s->step = step;
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s->shared_alloc_size = shared_alloc_size;
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s->percpu_alloc_size = percpu_alloc_size;
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s->histogram_alloc_size = histogram_alloc_size;
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s->n_histogram_entries = n_histogram_entries;
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s->histogram_boundaries = kmemdup(histogram_boundaries,
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s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL);
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if (!s->histogram_boundaries) {
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r = -ENOMEM;
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goto out;
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}
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s->program_id = kstrdup(program_id, GFP_KERNEL);
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if (!s->program_id) {
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r = -ENOMEM;
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goto out;
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}
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s->aux_data = kstrdup(aux_data, GFP_KERNEL);
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if (!s->aux_data) {
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r = -ENOMEM;
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goto out;
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}
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for (ni = 0; ni < n_entries; ni++) {
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atomic_set(&s->stat_shared[ni].in_flight[READ], 0);
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atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0);
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}
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if (s->n_histogram_entries) {
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unsigned long long *hi;
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hi = dm_kvzalloc(s->histogram_alloc_size, NUMA_NO_NODE);
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if (!hi) {
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r = -ENOMEM;
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goto out;
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}
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for (ni = 0; ni < n_entries; ni++) {
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s->stat_shared[ni].tmp.histogram = hi;
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hi += s->n_histogram_entries + 1;
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}
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}
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for_each_possible_cpu(cpu) {
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p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu));
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if (!p) {
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r = -ENOMEM;
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goto out;
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}
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s->stat_percpu[cpu] = p;
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if (s->n_histogram_entries) {
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unsigned long long *hi;
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hi = dm_kvzalloc(s->histogram_alloc_size, cpu_to_node(cpu));
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if (!hi) {
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r = -ENOMEM;
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goto out;
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}
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for (ni = 0; ni < n_entries; ni++) {
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p[ni].histogram = hi;
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hi += s->n_histogram_entries + 1;
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}
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}
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}
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/*
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* Suspend/resume to make sure there is no i/o in flight,
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* so that newly created statistics will be exact.
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*
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* (note: we couldn't suspend earlier because we must not
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* allocate memory while suspended)
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*/
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suspend_callback(md);
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mutex_lock(&stats->mutex);
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s->id = 0;
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list_for_each(l, &stats->list) {
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tmp_s = container_of(l, struct dm_stat, list_entry);
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if (WARN_ON(tmp_s->id < s->id)) {
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r = -EINVAL;
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goto out_unlock_resume;
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}
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if (tmp_s->id > s->id)
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break;
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if (unlikely(s->id == INT_MAX)) {
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r = -ENFILE;
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goto out_unlock_resume;
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}
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s->id++;
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}
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ret_id = s->id;
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list_add_tail_rcu(&s->list_entry, l);
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dm_stats_recalc_precise_timestamps(stats);
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mutex_unlock(&stats->mutex);
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resume_callback(md);
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return ret_id;
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out_unlock_resume:
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mutex_unlock(&stats->mutex);
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resume_callback(md);
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out:
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dm_stat_free(&s->rcu_head);
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return r;
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}
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static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id)
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{
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struct dm_stat *s;
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list_for_each_entry(s, &stats->list, list_entry) {
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if (s->id > id)
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break;
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if (s->id == id)
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return s;
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}
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return NULL;
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}
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static int dm_stats_delete(struct dm_stats *stats, int id)
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{
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struct dm_stat *s;
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int cpu;
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mutex_lock(&stats->mutex);
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s = __dm_stats_find(stats, id);
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if (!s) {
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mutex_unlock(&stats->mutex);
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return -ENOENT;
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}
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list_del_rcu(&s->list_entry);
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dm_stats_recalc_precise_timestamps(stats);
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mutex_unlock(&stats->mutex);
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/*
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* vfree can't be called from RCU callback
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*/
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for_each_possible_cpu(cpu)
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if (is_vmalloc_addr(s->stat_percpu) ||
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is_vmalloc_addr(s->stat_percpu[cpu][0].histogram))
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goto do_sync_free;
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if (is_vmalloc_addr(s) ||
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is_vmalloc_addr(s->stat_shared[0].tmp.histogram)) {
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do_sync_free:
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synchronize_rcu_expedited();
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dm_stat_free(&s->rcu_head);
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} else {
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WRITE_ONCE(dm_stat_need_rcu_barrier, 1);
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call_rcu(&s->rcu_head, dm_stat_free);
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}
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return 0;
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}
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static int dm_stats_list(struct dm_stats *stats, const char *program,
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char *result, unsigned maxlen)
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{
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struct dm_stat *s;
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sector_t len;
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unsigned sz = 0;
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/*
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* Output format:
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* <region_id>: <start_sector>+<length> <step> <program_id> <aux_data>
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*/
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mutex_lock(&stats->mutex);
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list_for_each_entry(s, &stats->list, list_entry) {
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if (!program || !strcmp(program, s->program_id)) {
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len = s->end - s->start;
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DMEMIT("%d: %llu+%llu %llu %s %s", s->id,
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(unsigned long long)s->start,
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(unsigned long long)len,
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(unsigned long long)s->step,
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s->program_id,
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s->aux_data);
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if (s->stat_flags & STAT_PRECISE_TIMESTAMPS)
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DMEMIT(" precise_timestamps");
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if (s->n_histogram_entries) {
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unsigned i;
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DMEMIT(" histogram:");
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for (i = 0; i < s->n_histogram_entries; i++) {
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if (i)
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DMEMIT(",");
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DMEMIT("%llu", s->histogram_boundaries[i]);
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}
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}
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DMEMIT("\n");
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}
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}
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mutex_unlock(&stats->mutex);
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return 1;
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}
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|
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static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared,
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struct dm_stat_percpu *p)
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{
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/*
|
|
* 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,
|
|
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 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, 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 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 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 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_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 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");
|