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gc.c
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// SPDX-License-Identifier: GPL-2.0
/*
* fs/f2fs/gc.c
*
* Copyright (c) 2012 Samsung Electronics Co., Ltd.
* http://www.samsung.com/
*/
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/f2fs_fs.h>
#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/freezer.h>
#include <linux/sched/signal.h>
#include <linux/random.h>
#include <linux/sched/mm.h>
#include "f2fs.h"
#include "node.h"
#include "segment.h"
#include "gc.h"
#include "iostat.h"
#include <trace/events/f2fs.h>
static struct kmem_cache *victim_entry_slab;
static unsigned int count_bits(const unsigned long *addr,
unsigned int offset, unsigned int len);
static int gc_thread_func(void *data)
{
struct f2fs_sb_info *sbi = data;
struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
wait_queue_head_t *fggc_wq = &sbi->gc_thread->fggc_wq;
unsigned int wait_ms;
struct f2fs_gc_control gc_control = {
.victim_segno = NULL_SEGNO,
.should_migrate_blocks = false,
.err_gc_skipped = false };
wait_ms = gc_th->min_sleep_time;
set_freezable();
do {
bool sync_mode, foreground = false;
wait_event_interruptible_timeout(*wq,
kthread_should_stop() || freezing(current) ||
waitqueue_active(fggc_wq) ||
gc_th->gc_wake,
msecs_to_jiffies(wait_ms));
if (test_opt(sbi, GC_MERGE) && waitqueue_active(fggc_wq))
foreground = true;
/* give it a try one time */
if (gc_th->gc_wake)
gc_th->gc_wake = false;
if (try_to_freeze() || f2fs_readonly(sbi->sb)) {
stat_other_skip_bggc_count(sbi);
continue;
}
if (kthread_should_stop())
break;
if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
increase_sleep_time(gc_th, &wait_ms);
stat_other_skip_bggc_count(sbi);
continue;
}
if (time_to_inject(sbi, FAULT_CHECKPOINT))
f2fs_stop_checkpoint(sbi, false,
STOP_CP_REASON_FAULT_INJECT);
if (!sb_start_write_trylock(sbi->sb)) {
stat_other_skip_bggc_count(sbi);
continue;
}
/*
* [GC triggering condition]
* 0. GC is not conducted currently.
* 1. There are enough dirty segments.
* 2. IO subsystem is idle by checking the # of writeback pages.
* 3. IO subsystem is idle by checking the # of requests in
* bdev's request list.
*
* Note) We have to avoid triggering GCs frequently.
* Because it is possible that some segments can be
* invalidated soon after by user update or deletion.
* So, I'd like to wait some time to collect dirty segments.
*/
if (sbi->gc_mode == GC_URGENT_HIGH ||
sbi->gc_mode == GC_URGENT_MID) {
wait_ms = gc_th->urgent_sleep_time;
f2fs_down_write(&sbi->gc_lock);
goto do_gc;
}
if (foreground) {
f2fs_down_write(&sbi->gc_lock);
goto do_gc;
} else if (!f2fs_down_write_trylock(&sbi->gc_lock)) {
stat_other_skip_bggc_count(sbi);
goto next;
}
if (!is_idle(sbi, GC_TIME)) {
increase_sleep_time(gc_th, &wait_ms);
f2fs_up_write(&sbi->gc_lock);
stat_io_skip_bggc_count(sbi);
goto next;
}
if (has_enough_invalid_blocks(sbi))
decrease_sleep_time(gc_th, &wait_ms);
else
increase_sleep_time(gc_th, &wait_ms);
do_gc:
if (!foreground)
stat_inc_bggc_count(sbi->stat_info);
sync_mode = F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC;
/* foreground GC was been triggered via f2fs_balance_fs() */
if (foreground)
sync_mode = false;
gc_control.init_gc_type = sync_mode ? FG_GC : BG_GC;
gc_control.no_bg_gc = foreground;
gc_control.nr_free_secs = foreground ? 1 : 0;
/* if return value is not zero, no victim was selected */
if (f2fs_gc(sbi, &gc_control)) {
/* don't bother wait_ms by foreground gc */
if (!foreground)
wait_ms = gc_th->no_gc_sleep_time;
} else {
/* reset wait_ms to default sleep time */
if (wait_ms == gc_th->no_gc_sleep_time)
wait_ms = gc_th->min_sleep_time;
}
if (foreground)
wake_up_all(&gc_th->fggc_wq);
trace_f2fs_background_gc(sbi->sb, wait_ms,
prefree_segments(sbi), free_segments(sbi));
/* balancing f2fs's metadata periodically */
f2fs_balance_fs_bg(sbi, true);
next:
if (sbi->gc_mode != GC_NORMAL) {
spin_lock(&sbi->gc_remaining_trials_lock);
if (sbi->gc_remaining_trials) {
sbi->gc_remaining_trials--;
if (!sbi->gc_remaining_trials)
sbi->gc_mode = GC_NORMAL;
}
spin_unlock(&sbi->gc_remaining_trials_lock);
}
sb_end_write(sbi->sb);
} while (!kthread_should_stop());
return 0;
}
int f2fs_start_gc_thread(struct f2fs_sb_info *sbi)
{
struct f2fs_gc_kthread *gc_th;
dev_t dev = sbi->sb->s_bdev->bd_dev;
gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
if (!gc_th)
return -ENOMEM;
gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;
gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
gc_th->gc_wake = false;
sbi->gc_thread = gc_th;
init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
init_waitqueue_head(&sbi->gc_thread->fggc_wq);
sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
"f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
if (IS_ERR(gc_th->f2fs_gc_task)) {
int err = PTR_ERR(gc_th->f2fs_gc_task);
kfree(gc_th);
sbi->gc_thread = NULL;
return err;
}
return 0;
}
void f2fs_stop_gc_thread(struct f2fs_sb_info *sbi)
{
struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
if (!gc_th)
return;
kthread_stop(gc_th->f2fs_gc_task);
wake_up_all(&gc_th->fggc_wq);
kfree(gc_th);
sbi->gc_thread = NULL;
}
static int select_gc_type(struct f2fs_sb_info *sbi, int gc_type)
{
int gc_mode;
if (gc_type == BG_GC) {
if (sbi->am.atgc_enabled)
gc_mode = GC_AT;
else
gc_mode = GC_CB;
} else {
gc_mode = GC_GREEDY;
}
switch (sbi->gc_mode) {
case GC_IDLE_CB:
gc_mode = GC_CB;
break;
case GC_IDLE_GREEDY:
case GC_URGENT_HIGH:
gc_mode = GC_GREEDY;
break;
case GC_IDLE_AT:
gc_mode = GC_AT;
break;
}
return gc_mode;
}
static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
int type, struct victim_sel_policy *p)
{
struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
if (p->alloc_mode == SSR) {
p->gc_mode = GC_GREEDY;
p->dirty_bitmap = dirty_i->dirty_segmap[type];
p->max_search = dirty_i->nr_dirty[type];
p->ofs_unit = 1;
} else if (p->alloc_mode == AT_SSR) {
p->gc_mode = GC_GREEDY;
p->dirty_bitmap = dirty_i->dirty_segmap[type];
p->max_search = dirty_i->nr_dirty[type];
p->ofs_unit = 1;
} else {
p->gc_mode = select_gc_type(sbi, gc_type);
p->ofs_unit = sbi->segs_per_sec;
if (__is_large_section(sbi)) {
p->dirty_bitmap = dirty_i->dirty_secmap;
p->max_search = count_bits(p->dirty_bitmap,
0, MAIN_SECS(sbi));
} else {
p->dirty_bitmap = dirty_i->dirty_segmap[DIRTY];
p->max_search = dirty_i->nr_dirty[DIRTY];
}
}
/*
* adjust candidates range, should select all dirty segments for
* foreground GC and urgent GC cases.
*/
if (gc_type != FG_GC &&
(sbi->gc_mode != GC_URGENT_HIGH) &&
(p->gc_mode != GC_AT && p->alloc_mode != AT_SSR) &&
p->max_search > sbi->max_victim_search)
p->max_search = sbi->max_victim_search;
/* let's select beginning hot/small space first in no_heap mode*/
if (f2fs_need_rand_seg(sbi))
p->offset = get_random_u32_below(MAIN_SECS(sbi) * sbi->segs_per_sec);
else if (test_opt(sbi, NOHEAP) &&
(type == CURSEG_HOT_DATA || IS_NODESEG(type)))
p->offset = 0;
else
p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
}
static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
struct victim_sel_policy *p)
{
/* SSR allocates in a segment unit */
if (p->alloc_mode == SSR)
return sbi->blocks_per_seg;
else if (p->alloc_mode == AT_SSR)
return UINT_MAX;
/* LFS */
if (p->gc_mode == GC_GREEDY)
return 2 * sbi->blocks_per_seg * p->ofs_unit;
else if (p->gc_mode == GC_CB)
return UINT_MAX;
else if (p->gc_mode == GC_AT)
return UINT_MAX;
else /* No other gc_mode */
return 0;
}
static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
{
struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
unsigned int secno;
/*
* If the gc_type is FG_GC, we can select victim segments
* selected by background GC before.
* Those segments guarantee they have small valid blocks.
*/
for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
if (sec_usage_check(sbi, secno))
continue;
clear_bit(secno, dirty_i->victim_secmap);
return GET_SEG_FROM_SEC(sbi, secno);
}
return NULL_SEGNO;
}
static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
{
struct sit_info *sit_i = SIT_I(sbi);
unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
unsigned long long mtime = 0;
unsigned int vblocks;
unsigned char age = 0;
unsigned char u;
unsigned int i;
unsigned int usable_segs_per_sec = f2fs_usable_segs_in_sec(sbi, segno);
for (i = 0; i < usable_segs_per_sec; i++)
mtime += get_seg_entry(sbi, start + i)->mtime;
vblocks = get_valid_blocks(sbi, segno, true);
mtime = div_u64(mtime, usable_segs_per_sec);
vblocks = div_u64(vblocks, usable_segs_per_sec);
u = (vblocks * 100) >> sbi->log_blocks_per_seg;
/* Handle if the system time has changed by the user */
if (mtime < sit_i->min_mtime)
sit_i->min_mtime = mtime;
if (mtime > sit_i->max_mtime)
sit_i->max_mtime = mtime;
if (sit_i->max_mtime != sit_i->min_mtime)
age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
sit_i->max_mtime - sit_i->min_mtime);
return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
}
static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
unsigned int segno, struct victim_sel_policy *p)
{
if (p->alloc_mode == SSR)
return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
/* alloc_mode == LFS */
if (p->gc_mode == GC_GREEDY)
return get_valid_blocks(sbi, segno, true);
else if (p->gc_mode == GC_CB)
return get_cb_cost(sbi, segno);
f2fs_bug_on(sbi, 1);
return 0;
}
static unsigned int count_bits(const unsigned long *addr,
unsigned int offset, unsigned int len)
{
unsigned int end = offset + len, sum = 0;
while (offset < end) {
if (test_bit(offset++, addr))
++sum;
}
return sum;
}
static bool f2fs_check_victim_tree(struct f2fs_sb_info *sbi,
struct rb_root_cached *root)
{
#ifdef CONFIG_F2FS_CHECK_FS
struct rb_node *cur = rb_first_cached(root), *next;
struct victim_entry *cur_ve, *next_ve;
while (cur) {
next = rb_next(cur);
if (!next)
return true;
cur_ve = rb_entry(cur, struct victim_entry, rb_node);
next_ve = rb_entry(next, struct victim_entry, rb_node);
if (cur_ve->mtime > next_ve->mtime) {
f2fs_info(sbi, "broken victim_rbtree, "
"cur_mtime(%llu) next_mtime(%llu)",
cur_ve->mtime, next_ve->mtime);
return false;
}
cur = next;
}
#endif
return true;
}
static struct victim_entry *__lookup_victim_entry(struct f2fs_sb_info *sbi,
unsigned long long mtime)
{
struct atgc_management *am = &sbi->am;
struct rb_node *node = am->root.rb_root.rb_node;
struct victim_entry *ve = NULL;
while (node) {
ve = rb_entry(node, struct victim_entry, rb_node);
if (mtime < ve->mtime)
node = node->rb_left;
else
node = node->rb_right;
}
return ve;
}
static struct victim_entry *__create_victim_entry(struct f2fs_sb_info *sbi,
unsigned long long mtime, unsigned int segno)
{
struct atgc_management *am = &sbi->am;
struct victim_entry *ve;
ve = f2fs_kmem_cache_alloc(victim_entry_slab, GFP_NOFS, true, NULL);
ve->mtime = mtime;
ve->segno = segno;
list_add_tail(&ve->list, &am->victim_list);
am->victim_count++;
return ve;
}
static void __insert_victim_entry(struct f2fs_sb_info *sbi,
unsigned long long mtime, unsigned int segno)
{
struct atgc_management *am = &sbi->am;
struct rb_root_cached *root = &am->root;
struct rb_node **p = &root->rb_root.rb_node;
struct rb_node *parent = NULL;
struct victim_entry *ve;
bool left_most = true;
/* look up rb tree to find parent node */
while (*p) {
parent = *p;
ve = rb_entry(parent, struct victim_entry, rb_node);
if (mtime < ve->mtime) {
p = &(*p)->rb_left;
} else {
p = &(*p)->rb_right;
left_most = false;
}
}
ve = __create_victim_entry(sbi, mtime, segno);
rb_link_node(&ve->rb_node, parent, p);
rb_insert_color_cached(&ve->rb_node, root, left_most);
}
static void add_victim_entry(struct f2fs_sb_info *sbi,
struct victim_sel_policy *p, unsigned int segno)
{
struct sit_info *sit_i = SIT_I(sbi);
unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
unsigned long long mtime = 0;
unsigned int i;
if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
if (p->gc_mode == GC_AT &&
get_valid_blocks(sbi, segno, true) == 0)
return;
}
for (i = 0; i < sbi->segs_per_sec; i++)
mtime += get_seg_entry(sbi, start + i)->mtime;
mtime = div_u64(mtime, sbi->segs_per_sec);
/* Handle if the system time has changed by the user */
if (mtime < sit_i->min_mtime)
sit_i->min_mtime = mtime;
if (mtime > sit_i->max_mtime)
sit_i->max_mtime = mtime;
if (mtime < sit_i->dirty_min_mtime)
sit_i->dirty_min_mtime = mtime;
if (mtime > sit_i->dirty_max_mtime)
sit_i->dirty_max_mtime = mtime;
/* don't choose young section as candidate */
if (sit_i->dirty_max_mtime - mtime < p->age_threshold)
return;
__insert_victim_entry(sbi, mtime, segno);
}
static void atgc_lookup_victim(struct f2fs_sb_info *sbi,
struct victim_sel_policy *p)
{
struct sit_info *sit_i = SIT_I(sbi);
struct atgc_management *am = &sbi->am;
struct rb_root_cached *root = &am->root;
struct rb_node *node;
struct victim_entry *ve;
unsigned long long total_time;
unsigned long long age, u, accu;
unsigned long long max_mtime = sit_i->dirty_max_mtime;
unsigned long long min_mtime = sit_i->dirty_min_mtime;
unsigned int sec_blocks = CAP_BLKS_PER_SEC(sbi);
unsigned int vblocks;
unsigned int dirty_threshold = max(am->max_candidate_count,
am->candidate_ratio *
am->victim_count / 100);
unsigned int age_weight = am->age_weight;
unsigned int cost;
unsigned int iter = 0;
if (max_mtime < min_mtime)
return;
max_mtime += 1;
total_time = max_mtime - min_mtime;
accu = div64_u64(ULLONG_MAX, total_time);
accu = min_t(unsigned long long, div_u64(accu, 100),
DEFAULT_ACCURACY_CLASS);
node = rb_first_cached(root);
next:
ve = rb_entry_safe(node, struct victim_entry, rb_node);
if (!ve)
return;
if (ve->mtime >= max_mtime || ve->mtime < min_mtime)
goto skip;
/* age = 10000 * x% * 60 */
age = div64_u64(accu * (max_mtime - ve->mtime), total_time) *
age_weight;
vblocks = get_valid_blocks(sbi, ve->segno, true);
f2fs_bug_on(sbi, !vblocks || vblocks == sec_blocks);
/* u = 10000 * x% * 40 */
u = div64_u64(accu * (sec_blocks - vblocks), sec_blocks) *
(100 - age_weight);
f2fs_bug_on(sbi, age + u >= UINT_MAX);
cost = UINT_MAX - (age + u);
iter++;
if (cost < p->min_cost ||
(cost == p->min_cost && age > p->oldest_age)) {
p->min_cost = cost;
p->oldest_age = age;
p->min_segno = ve->segno;
}
skip:
if (iter < dirty_threshold) {
node = rb_next(node);
goto next;
}
}
/*
* select candidates around source section in range of
* [target - dirty_threshold, target + dirty_threshold]
*/
static void atssr_lookup_victim(struct f2fs_sb_info *sbi,
struct victim_sel_policy *p)
{
struct sit_info *sit_i = SIT_I(sbi);
struct atgc_management *am = &sbi->am;
struct victim_entry *ve;
unsigned long long age;
unsigned long long max_mtime = sit_i->dirty_max_mtime;
unsigned long long min_mtime = sit_i->dirty_min_mtime;
unsigned int seg_blocks = sbi->blocks_per_seg;
unsigned int vblocks;
unsigned int dirty_threshold = max(am->max_candidate_count,
am->candidate_ratio *
am->victim_count / 100);
unsigned int cost, iter;
int stage = 0;
if (max_mtime < min_mtime)
return;
max_mtime += 1;
next_stage:
iter = 0;
ve = __lookup_victim_entry(sbi, p->age);
next_node:
if (!ve) {
if (stage++ == 0)
goto next_stage;
return;
}
if (ve->mtime >= max_mtime || ve->mtime < min_mtime)
goto skip_node;
age = max_mtime - ve->mtime;
vblocks = get_seg_entry(sbi, ve->segno)->ckpt_valid_blocks;
f2fs_bug_on(sbi, !vblocks);
/* rare case */
if (vblocks == seg_blocks)
goto skip_node;
iter++;
age = max_mtime - abs(p->age - age);
cost = UINT_MAX - vblocks;
if (cost < p->min_cost ||
(cost == p->min_cost && age > p->oldest_age)) {
p->min_cost = cost;
p->oldest_age = age;
p->min_segno = ve->segno;
}
skip_node:
if (iter < dirty_threshold) {
ve = rb_entry(stage == 0 ? rb_prev(&ve->rb_node) :
rb_next(&ve->rb_node),
struct victim_entry, rb_node);
goto next_node;
}
if (stage++ == 0)
goto next_stage;
}
static void lookup_victim_by_age(struct f2fs_sb_info *sbi,
struct victim_sel_policy *p)
{
f2fs_bug_on(sbi, !f2fs_check_victim_tree(sbi, &sbi->am.root));
if (p->gc_mode == GC_AT)
atgc_lookup_victim(sbi, p);
else if (p->alloc_mode == AT_SSR)
atssr_lookup_victim(sbi, p);
else
f2fs_bug_on(sbi, 1);
}
static void release_victim_entry(struct f2fs_sb_info *sbi)
{
struct atgc_management *am = &sbi->am;
struct victim_entry *ve, *tmp;
list_for_each_entry_safe(ve, tmp, &am->victim_list, list) {
list_del(&ve->list);
kmem_cache_free(victim_entry_slab, ve);
am->victim_count--;
}
am->root = RB_ROOT_CACHED;
f2fs_bug_on(sbi, am->victim_count);
f2fs_bug_on(sbi, !list_empty(&am->victim_list));
}
static bool f2fs_pin_section(struct f2fs_sb_info *sbi, unsigned int segno)
{
struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
if (!dirty_i->enable_pin_section)
return false;
if (!test_and_set_bit(secno, dirty_i->pinned_secmap))
dirty_i->pinned_secmap_cnt++;
return true;
}
static bool f2fs_pinned_section_exists(struct dirty_seglist_info *dirty_i)
{
return dirty_i->pinned_secmap_cnt;
}
static bool f2fs_section_is_pinned(struct dirty_seglist_info *dirty_i,
unsigned int secno)
{
return dirty_i->enable_pin_section &&
f2fs_pinned_section_exists(dirty_i) &&
test_bit(secno, dirty_i->pinned_secmap);
}
static void f2fs_unpin_all_sections(struct f2fs_sb_info *sbi, bool enable)
{
unsigned int bitmap_size = f2fs_bitmap_size(MAIN_SECS(sbi));
if (f2fs_pinned_section_exists(DIRTY_I(sbi))) {
memset(DIRTY_I(sbi)->pinned_secmap, 0, bitmap_size);
DIRTY_I(sbi)->pinned_secmap_cnt = 0;
}
DIRTY_I(sbi)->enable_pin_section = enable;
}
static int f2fs_gc_pinned_control(struct inode *inode, int gc_type,
unsigned int segno)
{
if (!f2fs_is_pinned_file(inode))
return 0;
if (gc_type != FG_GC)
return -EBUSY;
if (!f2fs_pin_section(F2FS_I_SB(inode), segno))
f2fs_pin_file_control(inode, true);
return -EAGAIN;
}
/*
* This function is called from two paths.
* One is garbage collection and the other is SSR segment selection.
* When it is called during GC, it just gets a victim segment
* and it does not remove it from dirty seglist.
* When it is called from SSR segment selection, it finds a segment
* which has minimum valid blocks and removes it from dirty seglist.
*/
int f2fs_get_victim(struct f2fs_sb_info *sbi, unsigned int *result,
int gc_type, int type, char alloc_mode,
unsigned long long age)
{
struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
struct sit_info *sm = SIT_I(sbi);
struct victim_sel_policy p;
unsigned int secno, last_victim;
unsigned int last_segment;
unsigned int nsearched;
bool is_atgc;
int ret = 0;
mutex_lock(&dirty_i->seglist_lock);
last_segment = MAIN_SECS(sbi) * sbi->segs_per_sec;
p.alloc_mode = alloc_mode;
p.age = age;
p.age_threshold = sbi->am.age_threshold;
retry:
select_policy(sbi, gc_type, type, &p);
p.min_segno = NULL_SEGNO;
p.oldest_age = 0;
p.min_cost = get_max_cost(sbi, &p);
is_atgc = (p.gc_mode == GC_AT || p.alloc_mode == AT_SSR);
nsearched = 0;
if (is_atgc)
SIT_I(sbi)->dirty_min_mtime = ULLONG_MAX;
if (*result != NULL_SEGNO) {
if (!get_valid_blocks(sbi, *result, false)) {
ret = -ENODATA;
goto out;
}
if (sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
ret = -EBUSY;
else
p.min_segno = *result;
goto out;
}
ret = -ENODATA;
if (p.max_search == 0)
goto out;
if (__is_large_section(sbi) && p.alloc_mode == LFS) {
if (sbi->next_victim_seg[BG_GC] != NULL_SEGNO) {
p.min_segno = sbi->next_victim_seg[BG_GC];
*result = p.min_segno;
sbi->next_victim_seg[BG_GC] = NULL_SEGNO;
goto got_result;
}
if (gc_type == FG_GC &&
sbi->next_victim_seg[FG_GC] != NULL_SEGNO) {
p.min_segno = sbi->next_victim_seg[FG_GC];
*result = p.min_segno;
sbi->next_victim_seg[FG_GC] = NULL_SEGNO;
goto got_result;
}
}
last_victim = sm->last_victim[p.gc_mode];
if (p.alloc_mode == LFS && gc_type == FG_GC) {
p.min_segno = check_bg_victims(sbi);
if (p.min_segno != NULL_SEGNO)
goto got_it;
}
while (1) {
unsigned long cost, *dirty_bitmap;
unsigned int unit_no, segno;
dirty_bitmap = p.dirty_bitmap;
unit_no = find_next_bit(dirty_bitmap,
last_segment / p.ofs_unit,
p.offset / p.ofs_unit);
segno = unit_no * p.ofs_unit;
if (segno >= last_segment) {
if (sm->last_victim[p.gc_mode]) {
last_segment =
sm->last_victim[p.gc_mode];
sm->last_victim[p.gc_mode] = 0;
p.offset = 0;
continue;
}
break;
}
p.offset = segno + p.ofs_unit;
nsearched++;
#ifdef CONFIG_F2FS_CHECK_FS
/*
* skip selecting the invalid segno (that is failed due to block
* validity check failure during GC) to avoid endless GC loop in
* such cases.
*/
if (test_bit(segno, sm->invalid_segmap))
goto next;
#endif
secno = GET_SEC_FROM_SEG(sbi, segno);
if (sec_usage_check(sbi, secno))
goto next;
/* Don't touch checkpointed data */
if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
if (p.alloc_mode == LFS) {
/*
* LFS is set to find source section during GC.
* The victim should have no checkpointed data.
*/
if (get_ckpt_valid_blocks(sbi, segno, true))
goto next;
} else {
/*
* SSR | AT_SSR are set to find target segment
* for writes which can be full by checkpointed
* and newly written blocks.
*/
if (!f2fs_segment_has_free_slot(sbi, segno))
goto next;
}
}
if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
goto next;
if (gc_type == FG_GC && f2fs_section_is_pinned(dirty_i, secno))
goto next;
if (is_atgc) {
add_victim_entry(sbi, &p, segno);
goto next;
}
cost = get_gc_cost(sbi, segno, &p);
if (p.min_cost > cost) {
p.min_segno = segno;
p.min_cost = cost;
}
next:
if (nsearched >= p.max_search) {
if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
sm->last_victim[p.gc_mode] =
last_victim + p.ofs_unit;
else
sm->last_victim[p.gc_mode] = segno + p.ofs_unit;
sm->last_victim[p.gc_mode] %=
(MAIN_SECS(sbi) * sbi->segs_per_sec);
break;
}
}
/* get victim for GC_AT/AT_SSR */
if (is_atgc) {
lookup_victim_by_age(sbi, &p);
release_victim_entry(sbi);
}
if (is_atgc && p.min_segno == NULL_SEGNO &&
sm->elapsed_time < p.age_threshold) {
p.age_threshold = 0;
goto retry;
}
if (p.min_segno != NULL_SEGNO) {
got_it:
*result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
got_result:
if (p.alloc_mode == LFS) {
secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
if (gc_type == FG_GC)
sbi->cur_victim_sec = secno;
else
set_bit(secno, dirty_i->victim_secmap);
}
ret = 0;
}
out:
if (p.min_segno != NULL_SEGNO)
trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
sbi->cur_victim_sec,
prefree_segments(sbi), free_segments(sbi));
mutex_unlock(&dirty_i->seglist_lock);
return ret;
}
static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
{
struct inode_entry *ie;
ie = radix_tree_lookup(&gc_list->iroot, ino);
if (ie)
return ie->inode;
return NULL;
}
static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
{
struct inode_entry *new_ie;
if (inode == find_gc_inode(gc_list, inode->i_ino)) {
iput(inode);
return;
}
new_ie = f2fs_kmem_cache_alloc(f2fs_inode_entry_slab,
GFP_NOFS, true, NULL);
new_ie->inode = inode;
f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
list_add_tail(&new_ie->list, &gc_list->ilist);
}
static void put_gc_inode(struct gc_inode_list *gc_list)
{
struct inode_entry *ie, *next_ie;
list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
iput(ie->inode);
list_del(&ie->list);
kmem_cache_free(f2fs_inode_entry_slab, ie);
}
}
static int check_valid_map(struct f2fs_sb_info *sbi,
unsigned int segno, int offset)
{
struct sit_info *sit_i = SIT_I(sbi);
struct seg_entry *sentry;
int ret;
down_read(&sit_i->sentry_lock);
sentry = get_seg_entry(sbi, segno);
ret = f2fs_test_bit(offset, sentry->cur_valid_map);
up_read(&sit_i->sentry_lock);
return ret;
}
/*
* This function compares node address got in summary with that in NAT.
* On validity, copy that node with cold status, otherwise (invalid node)
* ignore that.
*/
static int gc_node_segment(struct f2fs_sb_info *sbi,
struct f2fs_summary *sum, unsigned int segno, int gc_type)
{
struct f2fs_summary *entry;