swh:1:snp:173f8deb0c56c557784b4fd217e7608ac6197844
Tip revision: d8a5b80568a9cb66810e75b182018e9edb68e8ff authored by Linus Torvalds on 28 January 2018, 21:20:33 UTC
Linux 4.15
Linux 4.15
Tip revision: d8a5b80
pblk-gc.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.
*
* pblk-gc.c - pblk's garbage collector
*/
#include "pblk.h"
#include <linux/delay.h>
static void pblk_gc_free_gc_rq(struct pblk_gc_rq *gc_rq)
{
if (gc_rq->data)
vfree(gc_rq->data);
kfree(gc_rq);
}
static int pblk_gc_write(struct pblk *pblk)
{
struct pblk_gc *gc = &pblk->gc;
struct pblk_gc_rq *gc_rq, *tgc_rq;
LIST_HEAD(w_list);
spin_lock(&gc->w_lock);
if (list_empty(&gc->w_list)) {
spin_unlock(&gc->w_lock);
return 1;
}
list_cut_position(&w_list, &gc->w_list, gc->w_list.prev);
gc->w_entries = 0;
spin_unlock(&gc->w_lock);
list_for_each_entry_safe(gc_rq, tgc_rq, &w_list, list) {
pblk_write_gc_to_cache(pblk, gc_rq);
list_del(&gc_rq->list);
kref_put(&gc_rq->line->ref, pblk_line_put);
pblk_gc_free_gc_rq(gc_rq);
}
return 0;
}
static void pblk_gc_writer_kick(struct pblk_gc *gc)
{
wake_up_process(gc->gc_writer_ts);
}
static void pblk_put_line_back(struct pblk *pblk, struct pblk_line *line)
{
struct pblk_line_mgmt *l_mg = &pblk->l_mg;
struct list_head *move_list;
spin_lock(&line->lock);
WARN_ON(line->state != PBLK_LINESTATE_GC);
line->state = PBLK_LINESTATE_CLOSED;
move_list = pblk_line_gc_list(pblk, line);
spin_unlock(&line->lock);
if (move_list) {
spin_lock(&l_mg->gc_lock);
list_add_tail(&line->list, move_list);
spin_unlock(&l_mg->gc_lock);
}
}
static void pblk_gc_line_ws(struct work_struct *work)
{
struct pblk_line_ws *gc_rq_ws = container_of(work,
struct pblk_line_ws, ws);
struct pblk *pblk = gc_rq_ws->pblk;
struct nvm_tgt_dev *dev = pblk->dev;
struct nvm_geo *geo = &dev->geo;
struct pblk_gc *gc = &pblk->gc;
struct pblk_line *line = gc_rq_ws->line;
struct pblk_gc_rq *gc_rq = gc_rq_ws->priv;
int ret;
up(&gc->gc_sem);
gc_rq->data = vmalloc(gc_rq->nr_secs * geo->sec_size);
if (!gc_rq->data) {
pr_err("pblk: could not GC line:%d (%d/%d)\n",
line->id, *line->vsc, gc_rq->nr_secs);
goto out;
}
/* Read from GC victim block */
ret = pblk_submit_read_gc(pblk, gc_rq);
if (ret) {
pr_err("pblk: failed GC read in line:%d (err:%d)\n",
line->id, ret);
goto out;
}
if (!gc_rq->secs_to_gc)
goto out;
retry:
spin_lock(&gc->w_lock);
if (gc->w_entries >= PBLK_GC_RQ_QD) {
spin_unlock(&gc->w_lock);
pblk_gc_writer_kick(&pblk->gc);
usleep_range(128, 256);
goto retry;
}
gc->w_entries++;
list_add_tail(&gc_rq->list, &gc->w_list);
spin_unlock(&gc->w_lock);
pblk_gc_writer_kick(&pblk->gc);
kfree(gc_rq_ws);
return;
out:
pblk_gc_free_gc_rq(gc_rq);
kref_put(&line->ref, pblk_line_put);
kfree(gc_rq_ws);
}
static void pblk_gc_line_prepare_ws(struct work_struct *work)
{
struct pblk_line_ws *line_ws = container_of(work, struct pblk_line_ws,
ws);
struct pblk *pblk = line_ws->pblk;
struct pblk_line *line = line_ws->line;
struct pblk_line_mgmt *l_mg = &pblk->l_mg;
struct pblk_line_meta *lm = &pblk->lm;
struct pblk_gc *gc = &pblk->gc;
struct line_emeta *emeta_buf;
struct pblk_line_ws *gc_rq_ws;
struct pblk_gc_rq *gc_rq;
__le64 *lba_list;
unsigned long *invalid_bitmap;
int sec_left, nr_secs, bit;
int ret;
invalid_bitmap = kmalloc(lm->sec_bitmap_len, GFP_KERNEL);
if (!invalid_bitmap) {
pr_err("pblk: could not allocate GC invalid bitmap\n");
goto fail_free_ws;
}
emeta_buf = pblk_malloc(lm->emeta_len[0], l_mg->emeta_alloc_type,
GFP_KERNEL);
if (!emeta_buf) {
pr_err("pblk: cannot use GC emeta\n");
goto fail_free_bitmap;
}
ret = pblk_line_read_emeta(pblk, line, emeta_buf);
if (ret) {
pr_err("pblk: line %d read emeta failed (%d)\n", line->id, ret);
goto fail_free_emeta;
}
/* If this read fails, it means that emeta is corrupted. For now, leave
* the line untouched. TODO: Implement a recovery routine that scans and
* moves all sectors on the line.
*/
lba_list = pblk_recov_get_lba_list(pblk, emeta_buf);
if (!lba_list) {
pr_err("pblk: could not interpret emeta (line %d)\n", line->id);
goto fail_free_emeta;
}
spin_lock(&line->lock);
bitmap_copy(invalid_bitmap, line->invalid_bitmap, lm->sec_per_line);
sec_left = pblk_line_vsc(line);
spin_unlock(&line->lock);
if (sec_left < 0) {
pr_err("pblk: corrupted GC line (%d)\n", line->id);
goto fail_free_emeta;
}
bit = -1;
next_rq:
gc_rq = kmalloc(sizeof(struct pblk_gc_rq), GFP_KERNEL);
if (!gc_rq)
goto fail_free_emeta;
nr_secs = 0;
do {
bit = find_next_zero_bit(invalid_bitmap, lm->sec_per_line,
bit + 1);
if (bit > line->emeta_ssec)
break;
gc_rq->paddr_list[nr_secs] = bit;
gc_rq->lba_list[nr_secs++] = le64_to_cpu(lba_list[bit]);
} while (nr_secs < pblk->max_write_pgs);
if (unlikely(!nr_secs)) {
kfree(gc_rq);
goto out;
}
gc_rq->nr_secs = nr_secs;
gc_rq->line = line;
gc_rq_ws = kmalloc(sizeof(struct pblk_line_ws), GFP_KERNEL);
if (!gc_rq_ws)
goto fail_free_gc_rq;
gc_rq_ws->pblk = pblk;
gc_rq_ws->line = line;
gc_rq_ws->priv = gc_rq;
/* The write GC path can be much slower than the read GC one due to
* the budget imposed by the rate-limiter. Balance in case that we get
* back pressure from the write GC path.
*/
while (down_timeout(&gc->gc_sem, msecs_to_jiffies(30000)))
io_schedule();
kref_get(&line->ref);
INIT_WORK(&gc_rq_ws->ws, pblk_gc_line_ws);
queue_work(gc->gc_line_reader_wq, &gc_rq_ws->ws);
sec_left -= nr_secs;
if (sec_left > 0)
goto next_rq;
out:
pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
kfree(line_ws);
kfree(invalid_bitmap);
kref_put(&line->ref, pblk_line_put);
atomic_dec(&gc->read_inflight_gc);
return;
fail_free_gc_rq:
kfree(gc_rq);
fail_free_emeta:
pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
fail_free_bitmap:
kfree(invalid_bitmap);
fail_free_ws:
kfree(line_ws);
pblk_put_line_back(pblk, line);
kref_put(&line->ref, pblk_line_put);
atomic_dec(&gc->read_inflight_gc);
pr_err("pblk: Failed to GC line %d\n", line->id);
}
static int pblk_gc_line(struct pblk *pblk, struct pblk_line *line)
{
struct pblk_gc *gc = &pblk->gc;
struct pblk_line_ws *line_ws;
pr_debug("pblk: line '%d' being reclaimed for GC\n", line->id);
line_ws = kmalloc(sizeof(struct pblk_line_ws), GFP_KERNEL);
if (!line_ws)
return -ENOMEM;
line_ws->pblk = pblk;
line_ws->line = line;
atomic_inc(&gc->pipeline_gc);
INIT_WORK(&line_ws->ws, pblk_gc_line_prepare_ws);
queue_work(gc->gc_reader_wq, &line_ws->ws);
return 0;
}
static void pblk_gc_reader_kick(struct pblk_gc *gc)
{
wake_up_process(gc->gc_reader_ts);
}
static void pblk_gc_kick(struct pblk *pblk)
{
struct pblk_gc *gc = &pblk->gc;
pblk_gc_writer_kick(gc);
pblk_gc_reader_kick(gc);
/* If we're shutting down GC, let's not start it up again */
if (gc->gc_enabled) {
wake_up_process(gc->gc_ts);
mod_timer(&gc->gc_timer,
jiffies + msecs_to_jiffies(GC_TIME_MSECS));
}
}
static int pblk_gc_read(struct pblk *pblk)
{
struct pblk_gc *gc = &pblk->gc;
struct pblk_line *line;
spin_lock(&gc->r_lock);
if (list_empty(&gc->r_list)) {
spin_unlock(&gc->r_lock);
return 1;
}
line = list_first_entry(&gc->r_list, struct pblk_line, list);
list_del(&line->list);
spin_unlock(&gc->r_lock);
pblk_gc_kick(pblk);
if (pblk_gc_line(pblk, line))
pr_err("pblk: failed to GC line %d\n", line->id);
return 0;
}
static struct pblk_line *pblk_gc_get_victim_line(struct pblk *pblk,
struct list_head *group_list)
{
struct pblk_line *line, *victim;
int line_vsc, victim_vsc;
victim = list_first_entry(group_list, struct pblk_line, list);
list_for_each_entry(line, group_list, list) {
line_vsc = le32_to_cpu(*line->vsc);
victim_vsc = le32_to_cpu(*victim->vsc);
if (line_vsc < victim_vsc)
victim = line;
}
return victim;
}
static bool pblk_gc_should_run(struct pblk_gc *gc, struct pblk_rl *rl)
{
unsigned int nr_blocks_free, nr_blocks_need;
nr_blocks_need = pblk_rl_high_thrs(rl);
nr_blocks_free = pblk_rl_nr_free_blks(rl);
/* This is not critical, no need to take lock here */
return ((gc->gc_active) && (nr_blocks_need > nr_blocks_free));
}
void pblk_gc_free_full_lines(struct pblk *pblk)
{
struct pblk_line_mgmt *l_mg = &pblk->l_mg;
struct pblk_gc *gc = &pblk->gc;
struct pblk_line *line;
do {
spin_lock(&l_mg->gc_lock);
if (list_empty(&l_mg->gc_full_list)) {
spin_unlock(&l_mg->gc_lock);
return;
}
line = list_first_entry(&l_mg->gc_full_list,
struct pblk_line, list);
spin_lock(&line->lock);
WARN_ON(line->state != PBLK_LINESTATE_CLOSED);
line->state = PBLK_LINESTATE_GC;
spin_unlock(&line->lock);
list_del(&line->list);
spin_unlock(&l_mg->gc_lock);
atomic_inc(&gc->pipeline_gc);
kref_put(&line->ref, pblk_line_put);
} while (1);
}
/*
* Lines with no valid sectors will be returned to the free list immediately. If
* GC is activated - either because the free block count is under the determined
* threshold, or because it is being forced from user space - only lines with a
* high count of invalid sectors will be recycled.
*/
static void pblk_gc_run(struct pblk *pblk)
{
struct pblk_line_mgmt *l_mg = &pblk->l_mg;
struct pblk_gc *gc = &pblk->gc;
struct pblk_line *line;
struct list_head *group_list;
bool run_gc;
int read_inflight_gc, gc_group = 0, prev_group = 0;
pblk_gc_free_full_lines(pblk);
run_gc = pblk_gc_should_run(&pblk->gc, &pblk->rl);
if (!run_gc || (atomic_read(&gc->read_inflight_gc) >= PBLK_GC_L_QD))
return;
next_gc_group:
group_list = l_mg->gc_lists[gc_group++];
do {
spin_lock(&l_mg->gc_lock);
if (list_empty(group_list)) {
spin_unlock(&l_mg->gc_lock);
break;
}
line = pblk_gc_get_victim_line(pblk, group_list);
spin_lock(&line->lock);
WARN_ON(line->state != PBLK_LINESTATE_CLOSED);
line->state = PBLK_LINESTATE_GC;
spin_unlock(&line->lock);
list_del(&line->list);
spin_unlock(&l_mg->gc_lock);
spin_lock(&gc->r_lock);
list_add_tail(&line->list, &gc->r_list);
spin_unlock(&gc->r_lock);
read_inflight_gc = atomic_inc_return(&gc->read_inflight_gc);
pblk_gc_reader_kick(gc);
prev_group = 1;
/* No need to queue up more GC lines than we can handle */
run_gc = pblk_gc_should_run(&pblk->gc, &pblk->rl);
if (!run_gc || read_inflight_gc >= PBLK_GC_L_QD)
break;
} while (1);
if (!prev_group && pblk->rl.rb_state > gc_group &&
gc_group < PBLK_GC_NR_LISTS)
goto next_gc_group;
}
static void pblk_gc_timer(struct timer_list *t)
{
struct pblk *pblk = from_timer(pblk, t, gc.gc_timer);
pblk_gc_kick(pblk);
}
static int pblk_gc_ts(void *data)
{
struct pblk *pblk = data;
while (!kthread_should_stop()) {
pblk_gc_run(pblk);
set_current_state(TASK_INTERRUPTIBLE);
io_schedule();
}
return 0;
}
static int pblk_gc_writer_ts(void *data)
{
struct pblk *pblk = data;
while (!kthread_should_stop()) {
if (!pblk_gc_write(pblk))
continue;
set_current_state(TASK_INTERRUPTIBLE);
io_schedule();
}
return 0;
}
static int pblk_gc_reader_ts(void *data)
{
struct pblk *pblk = data;
struct pblk_gc *gc = &pblk->gc;
while (!kthread_should_stop()) {
if (!pblk_gc_read(pblk))
continue;
set_current_state(TASK_INTERRUPTIBLE);
io_schedule();
}
#ifdef CONFIG_NVM_DEBUG
pr_info("pblk: flushing gc pipeline, %d lines left\n",
atomic_read(&gc->pipeline_gc));
#endif
do {
if (!atomic_read(&gc->pipeline_gc))
break;
schedule();
} while (1);
return 0;
}
static void pblk_gc_start(struct pblk *pblk)
{
pblk->gc.gc_active = 1;
pr_debug("pblk: gc start\n");
}
void pblk_gc_should_start(struct pblk *pblk)
{
struct pblk_gc *gc = &pblk->gc;
if (gc->gc_enabled && !gc->gc_active) {
pblk_gc_start(pblk);
pblk_gc_kick(pblk);
}
}
/*
* If flush_wq == 1 then no lock should be held by the caller since
* flush_workqueue can sleep
*/
static void pblk_gc_stop(struct pblk *pblk, int flush_wq)
{
pblk->gc.gc_active = 0;
pr_debug("pblk: gc stop\n");
}
void pblk_gc_should_stop(struct pblk *pblk)
{
struct pblk_gc *gc = &pblk->gc;
if (gc->gc_active && !gc->gc_forced)
pblk_gc_stop(pblk, 0);
}
void pblk_gc_should_kick(struct pblk *pblk)
{
pblk_rl_update_rates(&pblk->rl);
}
void pblk_gc_sysfs_state_show(struct pblk *pblk, int *gc_enabled,
int *gc_active)
{
struct pblk_gc *gc = &pblk->gc;
spin_lock(&gc->lock);
*gc_enabled = gc->gc_enabled;
*gc_active = gc->gc_active;
spin_unlock(&gc->lock);
}
int pblk_gc_sysfs_force(struct pblk *pblk, int force)
{
struct pblk_gc *gc = &pblk->gc;
if (force < 0 || force > 1)
return -EINVAL;
spin_lock(&gc->lock);
gc->gc_forced = force;
if (force)
gc->gc_enabled = 1;
else
gc->gc_enabled = 0;
spin_unlock(&gc->lock);
pblk_gc_should_start(pblk);
return 0;
}
int pblk_gc_init(struct pblk *pblk)
{
struct pblk_gc *gc = &pblk->gc;
int ret;
gc->gc_ts = kthread_create(pblk_gc_ts, pblk, "pblk-gc-ts");
if (IS_ERR(gc->gc_ts)) {
pr_err("pblk: could not allocate GC main kthread\n");
return PTR_ERR(gc->gc_ts);
}
gc->gc_writer_ts = kthread_create(pblk_gc_writer_ts, pblk,
"pblk-gc-writer-ts");
if (IS_ERR(gc->gc_writer_ts)) {
pr_err("pblk: could not allocate GC writer kthread\n");
ret = PTR_ERR(gc->gc_writer_ts);
goto fail_free_main_kthread;
}
gc->gc_reader_ts = kthread_create(pblk_gc_reader_ts, pblk,
"pblk-gc-reader-ts");
if (IS_ERR(gc->gc_reader_ts)) {
pr_err("pblk: could not allocate GC reader kthread\n");
ret = PTR_ERR(gc->gc_reader_ts);
goto fail_free_writer_kthread;
}
timer_setup(&gc->gc_timer, pblk_gc_timer, 0);
mod_timer(&gc->gc_timer, jiffies + msecs_to_jiffies(GC_TIME_MSECS));
gc->gc_active = 0;
gc->gc_forced = 0;
gc->gc_enabled = 1;
gc->w_entries = 0;
atomic_set(&gc->read_inflight_gc, 0);
atomic_set(&gc->pipeline_gc, 0);
/* Workqueue that reads valid sectors from a line and submit them to the
* GC writer to be recycled.
*/
gc->gc_line_reader_wq = alloc_workqueue("pblk-gc-line-reader-wq",
WQ_MEM_RECLAIM | WQ_UNBOUND, PBLK_GC_MAX_READERS);
if (!gc->gc_line_reader_wq) {
pr_err("pblk: could not allocate GC line reader workqueue\n");
ret = -ENOMEM;
goto fail_free_reader_kthread;
}
/* Workqueue that prepare lines for GC */
gc->gc_reader_wq = alloc_workqueue("pblk-gc-line_wq",
WQ_MEM_RECLAIM | WQ_UNBOUND, 1);
if (!gc->gc_reader_wq) {
pr_err("pblk: could not allocate GC reader workqueue\n");
ret = -ENOMEM;
goto fail_free_reader_line_wq;
}
spin_lock_init(&gc->lock);
spin_lock_init(&gc->w_lock);
spin_lock_init(&gc->r_lock);
sema_init(&gc->gc_sem, PBLK_GC_RQ_QD);
INIT_LIST_HEAD(&gc->w_list);
INIT_LIST_HEAD(&gc->r_list);
return 0;
fail_free_reader_line_wq:
destroy_workqueue(gc->gc_line_reader_wq);
fail_free_reader_kthread:
kthread_stop(gc->gc_reader_ts);
fail_free_writer_kthread:
kthread_stop(gc->gc_writer_ts);
fail_free_main_kthread:
kthread_stop(gc->gc_ts);
return ret;
}
void pblk_gc_exit(struct pblk *pblk)
{
struct pblk_gc *gc = &pblk->gc;
gc->gc_enabled = 0;
del_timer_sync(&gc->gc_timer);
pblk_gc_stop(pblk, 1);
if (gc->gc_ts)
kthread_stop(gc->gc_ts);
if (gc->gc_reader_ts)
kthread_stop(gc->gc_reader_ts);
flush_workqueue(gc->gc_reader_wq);
if (gc->gc_reader_wq)
destroy_workqueue(gc->gc_reader_wq);
flush_workqueue(gc->gc_line_reader_wq);
if (gc->gc_line_reader_wq)
destroy_workqueue(gc->gc_line_reader_wq);
if (gc->gc_writer_ts)
kthread_stop(gc->gc_writer_ts);
}