linux/drivers/lightnvm/pblk-sysfs.c
Hans Holmberg 76758390f8 lightnvm: pblk: export write amplification counters to sysfs
In a SSD, write amplification, WA, is defined as the average
number of page writes per user page write. Write amplification
negatively affects write performance and decreases the lifetime
of the disk, so it's a useful metric to add to sysfs.

In plkb's case, the number of writes per user sector is the sum of:

    (1) number of user writes
    (2) number of sectors written by the garbage collector
    (3) number of sectors padded (i.e. due to syncs)

This patch adds persistent counters for 1-3 and two sysfs attributes
to export these along with WA calculated with five decimals:

    write_amp_mileage: the accumulated write amplification stats
                      for the lifetime of the pblk instance

    write_amp_trip: resetable stats to facilitate delta measurements,
                    values reset at creation and if 0 is written
                    to the attribute.

64-bit counters are used as a 32 bit counter would wrap around
already after about 17 TB worth of user data. It will take a
long long time before the 64 bit sector counters wrap around.

The counters are stored after the bad block bitmap in the first
emeta sector of each written line. There is plenty of space in the
first emeta sector, so we don't need to bump the major version of
the line data format.

Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <mb@lightnvm.io>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-29 17:29:09 -06:00

600 lines
15 KiB
C

/*
* Copyright (C) 2016 CNEX Labs
* Initial release: Javier Gonzalez <javier@cnexlabs.com>
* Matias Bjorling <matias@cnexlabs.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* Implementation of a physical block-device target for Open-channel SSDs.
*
* pblk-sysfs.c - pblk's sysfs
*
*/
#include "pblk.h"
static ssize_t pblk_sysfs_luns_show(struct pblk *pblk, char *page)
{
struct nvm_tgt_dev *dev = pblk->dev;
struct nvm_geo *geo = &dev->geo;
struct pblk_lun *rlun;
ssize_t sz = 0;
int i;
for (i = 0; i < geo->all_luns; i++) {
int active = 1;
rlun = &pblk->luns[i];
if (!down_trylock(&rlun->wr_sem)) {
active = 0;
up(&rlun->wr_sem);
}
sz += snprintf(page + sz, PAGE_SIZE - sz,
"pblk: pos:%d, ch:%d, lun:%d - %d\n",
i,
rlun->bppa.g.ch,
rlun->bppa.g.lun,
active);
}
return sz;
}
static ssize_t pblk_sysfs_rate_limiter(struct pblk *pblk, char *page)
{
int free_blocks, free_user_blocks, total_blocks;
int rb_user_max, rb_user_cnt;
int rb_gc_max, rb_gc_cnt, rb_budget, rb_state;
free_blocks = pblk_rl_nr_free_blks(&pblk->rl);
free_user_blocks = pblk_rl_nr_user_free_blks(&pblk->rl);
rb_user_max = pblk->rl.rb_user_max;
rb_user_cnt = atomic_read(&pblk->rl.rb_user_cnt);
rb_gc_max = pblk->rl.rb_gc_max;
rb_gc_cnt = atomic_read(&pblk->rl.rb_gc_cnt);
rb_budget = pblk->rl.rb_budget;
rb_state = pblk->rl.rb_state;
total_blocks = pblk->rl.total_blocks;
return snprintf(page, PAGE_SIZE,
"u:%u/%u,gc:%u/%u(%u)(stop:<%u,full:>%u,free:%d/%d/%d)-%d\n",
rb_user_cnt,
rb_user_max,
rb_gc_cnt,
rb_gc_max,
rb_state,
rb_budget,
pblk->rl.high,
free_blocks,
free_user_blocks,
total_blocks,
READ_ONCE(pblk->rl.rb_user_active));
}
static ssize_t pblk_sysfs_gc_state_show(struct pblk *pblk, char *page)
{
int gc_enabled, gc_active;
pblk_gc_sysfs_state_show(pblk, &gc_enabled, &gc_active);
return snprintf(page, PAGE_SIZE, "gc_enabled=%d, gc_active=%d\n",
gc_enabled, gc_active);
}
static ssize_t pblk_sysfs_stats(struct pblk *pblk, char *page)
{
ssize_t sz;
sz = snprintf(page, PAGE_SIZE,
"read_failed=%lu, read_high_ecc=%lu, read_empty=%lu, read_failed_gc=%lu, write_failed=%lu, erase_failed=%lu\n",
atomic_long_read(&pblk->read_failed),
atomic_long_read(&pblk->read_high_ecc),
atomic_long_read(&pblk->read_empty),
atomic_long_read(&pblk->read_failed_gc),
atomic_long_read(&pblk->write_failed),
atomic_long_read(&pblk->erase_failed));
return sz;
}
static ssize_t pblk_sysfs_write_buffer(struct pblk *pblk, char *page)
{
return pblk_rb_sysfs(&pblk->rwb, page);
}
static ssize_t pblk_sysfs_ppaf(struct pblk *pblk, char *page)
{
struct nvm_tgt_dev *dev = pblk->dev;
struct nvm_geo *geo = &dev->geo;
ssize_t sz = 0;
sz = snprintf(page, PAGE_SIZE - sz,
"g:(b:%d)blk:%d/%d,pg:%d/%d,lun:%d/%d,ch:%d/%d,pl:%d/%d,sec:%d/%d\n",
pblk->ppaf_bitsize,
pblk->ppaf.blk_offset, geo->ppaf.blk_len,
pblk->ppaf.pg_offset, geo->ppaf.pg_len,
pblk->ppaf.lun_offset, geo->ppaf.lun_len,
pblk->ppaf.ch_offset, geo->ppaf.ch_len,
pblk->ppaf.pln_offset, geo->ppaf.pln_len,
pblk->ppaf.sec_offset, geo->ppaf.sect_len);
sz += snprintf(page + sz, PAGE_SIZE - sz,
"d:blk:%d/%d,pg:%d/%d,lun:%d/%d,ch:%d/%d,pl:%d/%d,sec:%d/%d\n",
geo->ppaf.blk_offset, geo->ppaf.blk_len,
geo->ppaf.pg_offset, geo->ppaf.pg_len,
geo->ppaf.lun_offset, geo->ppaf.lun_len,
geo->ppaf.ch_offset, geo->ppaf.ch_len,
geo->ppaf.pln_offset, geo->ppaf.pln_len,
geo->ppaf.sect_offset, geo->ppaf.sect_len);
return sz;
}
static ssize_t pblk_sysfs_lines(struct pblk *pblk, char *page)
{
struct nvm_tgt_dev *dev = pblk->dev;
struct nvm_geo *geo = &dev->geo;
struct pblk_line_meta *lm = &pblk->lm;
struct pblk_line_mgmt *l_mg = &pblk->l_mg;
struct pblk_line *line;
ssize_t sz = 0;
int nr_free_lines;
int cur_data, cur_log;
int free_line_cnt = 0, closed_line_cnt = 0, emeta_line_cnt = 0;
int d_line_cnt = 0, l_line_cnt = 0;
int gc_full = 0, gc_high = 0, gc_mid = 0, gc_low = 0, gc_empty = 0;
int bad = 0, cor = 0;
int msecs = 0, cur_sec = 0, vsc = 0, sec_in_line = 0;
int map_weight = 0, meta_weight = 0;
spin_lock(&l_mg->free_lock);
cur_data = (l_mg->data_line) ? l_mg->data_line->id : -1;
cur_log = (l_mg->log_line) ? l_mg->log_line->id : -1;
nr_free_lines = l_mg->nr_free_lines;
list_for_each_entry(line, &l_mg->free_list, list)
free_line_cnt++;
spin_unlock(&l_mg->free_lock);
spin_lock(&l_mg->close_lock);
list_for_each_entry(line, &l_mg->emeta_list, list)
emeta_line_cnt++;
spin_unlock(&l_mg->close_lock);
spin_lock(&l_mg->gc_lock);
list_for_each_entry(line, &l_mg->gc_full_list, list) {
if (line->type == PBLK_LINETYPE_DATA)
d_line_cnt++;
else if (line->type == PBLK_LINETYPE_LOG)
l_line_cnt++;
closed_line_cnt++;
gc_full++;
}
list_for_each_entry(line, &l_mg->gc_high_list, list) {
if (line->type == PBLK_LINETYPE_DATA)
d_line_cnt++;
else if (line->type == PBLK_LINETYPE_LOG)
l_line_cnt++;
closed_line_cnt++;
gc_high++;
}
list_for_each_entry(line, &l_mg->gc_mid_list, list) {
if (line->type == PBLK_LINETYPE_DATA)
d_line_cnt++;
else if (line->type == PBLK_LINETYPE_LOG)
l_line_cnt++;
closed_line_cnt++;
gc_mid++;
}
list_for_each_entry(line, &l_mg->gc_low_list, list) {
if (line->type == PBLK_LINETYPE_DATA)
d_line_cnt++;
else if (line->type == PBLK_LINETYPE_LOG)
l_line_cnt++;
closed_line_cnt++;
gc_low++;
}
list_for_each_entry(line, &l_mg->gc_empty_list, list) {
if (line->type == PBLK_LINETYPE_DATA)
d_line_cnt++;
else if (line->type == PBLK_LINETYPE_LOG)
l_line_cnt++;
closed_line_cnt++;
gc_empty++;
}
list_for_each_entry(line, &l_mg->bad_list, list)
bad++;
list_for_each_entry(line, &l_mg->corrupt_list, list)
cor++;
spin_unlock(&l_mg->gc_lock);
spin_lock(&l_mg->free_lock);
if (l_mg->data_line) {
cur_sec = l_mg->data_line->cur_sec;
msecs = l_mg->data_line->left_msecs;
vsc = le32_to_cpu(*l_mg->data_line->vsc);
sec_in_line = l_mg->data_line->sec_in_line;
meta_weight = bitmap_weight(&l_mg->meta_bitmap,
PBLK_DATA_LINES);
map_weight = bitmap_weight(l_mg->data_line->map_bitmap,
lm->sec_per_line);
}
spin_unlock(&l_mg->free_lock);
if (nr_free_lines != free_line_cnt)
pr_err("pblk: corrupted free line list:%d/%d\n",
nr_free_lines, free_line_cnt);
sz = snprintf(page, PAGE_SIZE - sz,
"line: nluns:%d, nblks:%d, nsecs:%d\n",
geo->all_luns, lm->blk_per_line, lm->sec_per_line);
sz += snprintf(page + sz, PAGE_SIZE - sz,
"lines:d:%d,l:%d-f:%d,m:%d/%d,c:%d,b:%d,co:%d(d:%d,l:%d)t:%d\n",
cur_data, cur_log,
nr_free_lines,
emeta_line_cnt, meta_weight,
closed_line_cnt,
bad, cor,
d_line_cnt, l_line_cnt,
l_mg->nr_lines);
sz += snprintf(page + sz, PAGE_SIZE - sz,
"GC: full:%d, high:%d, mid:%d, low:%d, empty:%d, queue:%d\n",
gc_full, gc_high, gc_mid, gc_low, gc_empty,
atomic_read(&pblk->gc.read_inflight_gc));
sz += snprintf(page + sz, PAGE_SIZE - sz,
"data (%d) cur:%d, left:%d, vsc:%d, s:%d, map:%d/%d (%d)\n",
cur_data, cur_sec, msecs, vsc, sec_in_line,
map_weight, lm->sec_per_line,
atomic_read(&pblk->inflight_io));
return sz;
}
static ssize_t pblk_sysfs_lines_info(struct pblk *pblk, char *page)
{
struct nvm_tgt_dev *dev = pblk->dev;
struct nvm_geo *geo = &dev->geo;
struct pblk_line_meta *lm = &pblk->lm;
ssize_t sz = 0;
sz = snprintf(page, PAGE_SIZE - sz,
"smeta - len:%d, secs:%d\n",
lm->smeta_len, lm->smeta_sec);
sz += snprintf(page + sz, PAGE_SIZE - sz,
"emeta - len:%d, sec:%d, bb_start:%d\n",
lm->emeta_len[0], lm->emeta_sec[0],
lm->emeta_bb);
sz += snprintf(page + sz, PAGE_SIZE - sz,
"bitmap lengths: sec:%d, blk:%d, lun:%d\n",
lm->sec_bitmap_len,
lm->blk_bitmap_len,
lm->lun_bitmap_len);
sz += snprintf(page + sz, PAGE_SIZE - sz,
"blk_line:%d, sec_line:%d, sec_blk:%d\n",
lm->blk_per_line,
lm->sec_per_line,
geo->sec_per_chk);
return sz;
}
static ssize_t pblk_sysfs_get_sec_per_write(struct pblk *pblk, char *page)
{
return snprintf(page, PAGE_SIZE, "%d\n", pblk->sec_per_write);
}
static ssize_t pblk_get_write_amp(u64 user, u64 gc, u64 pad,
char *page)
{
int sz;
sz = snprintf(page, PAGE_SIZE,
"user:%lld gc:%lld pad:%lld WA:",
user, gc, pad);
if (!user) {
sz += snprintf(page + sz, PAGE_SIZE - sz, "NaN\n");
} else {
u64 wa_int;
u32 wa_frac;
wa_int = (user + gc + pad) * 100000;
wa_int = div_u64(wa_int, user);
wa_int = div_u64_rem(wa_int, 100000, &wa_frac);
sz += snprintf(page + sz, PAGE_SIZE - sz, "%llu.%05u\n",
wa_int, wa_frac);
}
return sz;
}
static ssize_t pblk_sysfs_get_write_amp_mileage(struct pblk *pblk, char *page)
{
return pblk_get_write_amp(atomic64_read(&pblk->user_wa),
atomic64_read(&pblk->gc_wa), atomic64_read(&pblk->pad_wa),
page);
}
static ssize_t pblk_sysfs_get_write_amp_trip(struct pblk *pblk, char *page)
{
return pblk_get_write_amp(
atomic64_read(&pblk->user_wa) - pblk->user_rst_wa,
atomic64_read(&pblk->gc_wa) - pblk->gc_rst_wa,
atomic64_read(&pblk->pad_wa) - pblk->pad_rst_wa, page);
}
#ifdef CONFIG_NVM_DEBUG
static ssize_t pblk_sysfs_stats_debug(struct pblk *pblk, char *page)
{
return snprintf(page, PAGE_SIZE,
"%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\n",
atomic_long_read(&pblk->inflight_writes),
atomic_long_read(&pblk->inflight_reads),
atomic_long_read(&pblk->req_writes),
atomic_long_read(&pblk->nr_flush),
atomic_long_read(&pblk->padded_writes),
atomic_long_read(&pblk->padded_wb),
atomic_long_read(&pblk->sub_writes),
atomic_long_read(&pblk->sync_writes),
atomic_long_read(&pblk->recov_writes),
atomic_long_read(&pblk->recov_gc_writes),
atomic_long_read(&pblk->recov_gc_reads),
atomic_long_read(&pblk->cache_reads),
atomic_long_read(&pblk->sync_reads));
}
#endif
static ssize_t pblk_sysfs_gc_force(struct pblk *pblk, const char *page,
size_t len)
{
size_t c_len;
int force;
c_len = strcspn(page, "\n");
if (c_len >= len)
return -EINVAL;
if (kstrtouint(page, 0, &force))
return -EINVAL;
pblk_gc_sysfs_force(pblk, force);
return len;
}
static ssize_t pblk_sysfs_set_sec_per_write(struct pblk *pblk,
const char *page, size_t len)
{
size_t c_len;
int sec_per_write;
c_len = strcspn(page, "\n");
if (c_len >= len)
return -EINVAL;
if (kstrtouint(page, 0, &sec_per_write))
return -EINVAL;
if (sec_per_write < pblk->min_write_pgs
|| sec_per_write > pblk->max_write_pgs
|| sec_per_write % pblk->min_write_pgs != 0)
return -EINVAL;
pblk_set_sec_per_write(pblk, sec_per_write);
return len;
}
static ssize_t pblk_sysfs_set_write_amp_trip(struct pblk *pblk,
const char *page, size_t len)
{
size_t c_len;
int reset_value;
c_len = strcspn(page, "\n");
if (c_len >= len)
return -EINVAL;
if (kstrtouint(page, 0, &reset_value))
return -EINVAL;
if (reset_value != 0)
return -EINVAL;
pblk->user_rst_wa = atomic64_read(&pblk->user_wa);
pblk->pad_rst_wa = atomic64_read(&pblk->pad_wa);
pblk->gc_rst_wa = atomic64_read(&pblk->gc_wa);
return len;
}
static struct attribute sys_write_luns = {
.name = "write_luns",
.mode = 0444,
};
static struct attribute sys_rate_limiter_attr = {
.name = "rate_limiter",
.mode = 0444,
};
static struct attribute sys_gc_state = {
.name = "gc_state",
.mode = 0444,
};
static struct attribute sys_errors_attr = {
.name = "errors",
.mode = 0444,
};
static struct attribute sys_rb_attr = {
.name = "write_buffer",
.mode = 0444,
};
static struct attribute sys_stats_ppaf_attr = {
.name = "ppa_format",
.mode = 0444,
};
static struct attribute sys_lines_attr = {
.name = "lines",
.mode = 0444,
};
static struct attribute sys_lines_info_attr = {
.name = "lines_info",
.mode = 0444,
};
static struct attribute sys_gc_force = {
.name = "gc_force",
.mode = 0200,
};
static struct attribute sys_max_sec_per_write = {
.name = "max_sec_per_write",
.mode = 0644,
};
static struct attribute sys_write_amp_mileage = {
.name = "write_amp_mileage",
.mode = 0444,
};
static struct attribute sys_write_amp_trip = {
.name = "write_amp_trip",
.mode = 0644,
};
#ifdef CONFIG_NVM_DEBUG
static struct attribute sys_stats_debug_attr = {
.name = "stats",
.mode = 0444,
};
#endif
static struct attribute *pblk_attrs[] = {
&sys_write_luns,
&sys_rate_limiter_attr,
&sys_errors_attr,
&sys_gc_state,
&sys_gc_force,
&sys_max_sec_per_write,
&sys_rb_attr,
&sys_stats_ppaf_attr,
&sys_lines_attr,
&sys_lines_info_attr,
&sys_write_amp_mileage,
&sys_write_amp_trip,
#ifdef CONFIG_NVM_DEBUG
&sys_stats_debug_attr,
#endif
NULL,
};
static ssize_t pblk_sysfs_show(struct kobject *kobj, struct attribute *attr,
char *buf)
{
struct pblk *pblk = container_of(kobj, struct pblk, kobj);
if (strcmp(attr->name, "rate_limiter") == 0)
return pblk_sysfs_rate_limiter(pblk, buf);
else if (strcmp(attr->name, "write_luns") == 0)
return pblk_sysfs_luns_show(pblk, buf);
else if (strcmp(attr->name, "gc_state") == 0)
return pblk_sysfs_gc_state_show(pblk, buf);
else if (strcmp(attr->name, "errors") == 0)
return pblk_sysfs_stats(pblk, buf);
else if (strcmp(attr->name, "write_buffer") == 0)
return pblk_sysfs_write_buffer(pblk, buf);
else if (strcmp(attr->name, "ppa_format") == 0)
return pblk_sysfs_ppaf(pblk, buf);
else if (strcmp(attr->name, "lines") == 0)
return pblk_sysfs_lines(pblk, buf);
else if (strcmp(attr->name, "lines_info") == 0)
return pblk_sysfs_lines_info(pblk, buf);
else if (strcmp(attr->name, "max_sec_per_write") == 0)
return pblk_sysfs_get_sec_per_write(pblk, buf);
else if (strcmp(attr->name, "write_amp_mileage") == 0)
return pblk_sysfs_get_write_amp_mileage(pblk, buf);
else if (strcmp(attr->name, "write_amp_trip") == 0)
return pblk_sysfs_get_write_amp_trip(pblk, buf);
#ifdef CONFIG_NVM_DEBUG
else if (strcmp(attr->name, "stats") == 0)
return pblk_sysfs_stats_debug(pblk, buf);
#endif
return 0;
}
static ssize_t pblk_sysfs_store(struct kobject *kobj, struct attribute *attr,
const char *buf, size_t len)
{
struct pblk *pblk = container_of(kobj, struct pblk, kobj);
if (strcmp(attr->name, "gc_force") == 0)
return pblk_sysfs_gc_force(pblk, buf, len);
else if (strcmp(attr->name, "max_sec_per_write") == 0)
return pblk_sysfs_set_sec_per_write(pblk, buf, len);
else if (strcmp(attr->name, "write_amp_trip") == 0)
return pblk_sysfs_set_write_amp_trip(pblk, buf, len);
return 0;
}
static const struct sysfs_ops pblk_sysfs_ops = {
.show = pblk_sysfs_show,
.store = pblk_sysfs_store,
};
static struct kobj_type pblk_ktype = {
.sysfs_ops = &pblk_sysfs_ops,
.default_attrs = pblk_attrs,
};
int pblk_sysfs_init(struct gendisk *tdisk)
{
struct pblk *pblk = tdisk->private_data;
struct device *parent_dev = disk_to_dev(pblk->disk);
int ret;
ret = kobject_init_and_add(&pblk->kobj, &pblk_ktype,
kobject_get(&parent_dev->kobj),
"%s", "pblk");
if (ret) {
pr_err("pblk: could not register %s/pblk\n",
tdisk->disk_name);
return ret;
}
kobject_uevent(&pblk->kobj, KOBJ_ADD);
return 0;
}
void pblk_sysfs_exit(struct gendisk *tdisk)
{
struct pblk *pblk = tdisk->private_data;
kobject_uevent(&pblk->kobj, KOBJ_REMOVE);
kobject_del(&pblk->kobj);
kobject_put(&pblk->kobj);
}