linux/fs/f2fs/gc.c
Namjae Jeon ec7b1f2dd1 f2fs: name gc task as per the block device
Currently GC task is started for each f2fs formatted/mounted device.
But, when we check the task list, using 'ps', there is no distinguishing
factor between the tasks. So, name the task as per the block device just
like the flusher threads.
Also, remove the macro GC_THREAD_NAME and instead use the name: f2fs_gc
to avoid name length truncation, as the command length is 16
-> TASK_COMM_LEN 16 and example name like:
f2fs_gc_task:8:16 -> this exceeds name length

Before Patch for 2 F2FS formatted partitions:
root  28061  0.0  0.0  0 0 ? S 10:31   0:00 [f2fs_gc_task]
root  28087  0.0  0.0  0 0 ? S 10:32   0:00 [f2fs_gc_task]

After Patch:
root  16756  0.0  0.0  0  0 ?  S  14:57   0:00 [f2fs_gc-8:18]
root  16765  0.0  0.0  0  0 ?  S  14:57   0:00 [f2fs_gc-8:19]

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-02-12 07:15:02 +09:00

720 lines
17 KiB
C

/*
* fs/f2fs/gc.c
*
* Copyright (c) 2012 Samsung Electronics Co., Ltd.
* http://www.samsung.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.
*/
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/backing-dev.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
#include <linux/f2fs_fs.h>
#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/freezer.h>
#include <linux/blkdev.h>
#include "f2fs.h"
#include "node.h"
#include "segment.h"
#include "gc.h"
static struct kmem_cache *winode_slab;
static int gc_thread_func(void *data)
{
struct f2fs_sb_info *sbi = data;
wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
long wait_ms;
wait_ms = GC_THREAD_MIN_SLEEP_TIME;
do {
if (try_to_freeze())
continue;
else
wait_event_interruptible_timeout(*wq,
kthread_should_stop(),
msecs_to_jiffies(wait_ms));
if (kthread_should_stop())
break;
if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
wait_ms = GC_THREAD_MAX_SLEEP_TIME;
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 too much 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 (!mutex_trylock(&sbi->gc_mutex))
continue;
if (!is_idle(sbi)) {
wait_ms = increase_sleep_time(wait_ms);
mutex_unlock(&sbi->gc_mutex);
continue;
}
if (has_enough_invalid_blocks(sbi))
wait_ms = decrease_sleep_time(wait_ms);
else
wait_ms = increase_sleep_time(wait_ms);
sbi->bg_gc++;
if (f2fs_gc(sbi) == GC_NONE)
wait_ms = GC_THREAD_NOGC_SLEEP_TIME;
else if (wait_ms == GC_THREAD_NOGC_SLEEP_TIME)
wait_ms = GC_THREAD_MAX_SLEEP_TIME;
} while (!kthread_should_stop());
return 0;
}
int start_gc_thread(struct f2fs_sb_info *sbi)
{
struct f2fs_gc_kthread *gc_th;
dev_t dev = sbi->sb->s_bdev->bd_dev;
if (!test_opt(sbi, BG_GC))
return 0;
gc_th = kmalloc(sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
if (!gc_th)
return -ENOMEM;
sbi->gc_thread = gc_th;
init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
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)) {
kfree(gc_th);
return -ENOMEM;
}
return 0;
}
void 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);
kfree(gc_th);
sbi->gc_thread = NULL;
}
static int select_gc_type(int gc_type)
{
return (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
}
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) {
p->gc_mode = GC_GREEDY;
p->dirty_segmap = dirty_i->dirty_segmap[type];
p->ofs_unit = 1;
} else {
p->gc_mode = select_gc_type(gc_type);
p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
p->ofs_unit = sbi->segs_per_sec;
}
p->offset = sbi->last_victim[p->gc_mode];
}
static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
struct victim_sel_policy *p)
{
if (p->gc_mode == GC_GREEDY)
return (1 << sbi->log_blocks_per_seg) * p->ofs_unit;
else if (p->gc_mode == GC_CB)
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 segno;
/*
* 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.
*/
segno = find_next_bit(dirty_i->victim_segmap[BG_GC],
TOTAL_SEGS(sbi), 0);
if (segno < TOTAL_SEGS(sbi)) {
clear_bit(segno, dirty_i->victim_segmap[BG_GC]);
return segno;
}
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_SECNO(sbi, segno);
unsigned int start = secno * sbi->segs_per_sec;
unsigned long long mtime = 0;
unsigned int vblocks;
unsigned char age = 0;
unsigned char u;
unsigned int i;
for (i = 0; i < sbi->segs_per_sec; i++)
mtime += get_seg_entry(sbi, start + i)->mtime;
vblocks = get_valid_blocks(sbi, segno, sbi->segs_per_sec);
mtime = div_u64(mtime, sbi->segs_per_sec);
vblocks = div_u64(vblocks, sbi->segs_per_sec);
u = (vblocks * 100) >> sbi->log_blocks_per_seg;
/* Handle if the system time is changed by 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 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, sbi->segs_per_sec);
else
return get_cb_cost(sbi, segno);
}
/*
* This function is called from two pathes.
* 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.
*/
static int get_victim_by_default(struct f2fs_sb_info *sbi,
unsigned int *result, int gc_type, int type, char alloc_mode)
{
struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
struct victim_sel_policy p;
unsigned int segno;
int nsearched = 0;
p.alloc_mode = alloc_mode;
select_policy(sbi, gc_type, type, &p);
p.min_segno = NULL_SEGNO;
p.min_cost = get_max_cost(sbi, &p);
mutex_lock(&dirty_i->seglist_lock);
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;
segno = find_next_bit(p.dirty_segmap,
TOTAL_SEGS(sbi), p.offset);
if (segno >= TOTAL_SEGS(sbi)) {
if (sbi->last_victim[p.gc_mode]) {
sbi->last_victim[p.gc_mode] = 0;
p.offset = 0;
continue;
}
break;
}
p.offset = ((segno / p.ofs_unit) * p.ofs_unit) + p.ofs_unit;
if (test_bit(segno, dirty_i->victim_segmap[FG_GC]))
continue;
if (gc_type == BG_GC &&
test_bit(segno, dirty_i->victim_segmap[BG_GC]))
continue;
if (IS_CURSEC(sbi, GET_SECNO(sbi, segno)))
continue;
cost = get_gc_cost(sbi, segno, &p);
if (p.min_cost > cost) {
p.min_segno = segno;
p.min_cost = cost;
}
if (cost == get_max_cost(sbi, &p))
continue;
if (nsearched++ >= MAX_VICTIM_SEARCH) {
sbi->last_victim[p.gc_mode] = segno;
break;
}
}
got_it:
if (p.min_segno != NULL_SEGNO) {
*result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
if (p.alloc_mode == LFS) {
int i;
for (i = 0; i < p.ofs_unit; i++)
set_bit(*result + i,
dirty_i->victim_segmap[gc_type]);
}
}
mutex_unlock(&dirty_i->seglist_lock);
return (p.min_segno == NULL_SEGNO) ? 0 : 1;
}
static const struct victim_selection default_v_ops = {
.get_victim = get_victim_by_default,
};
static struct inode *find_gc_inode(nid_t ino, struct list_head *ilist)
{
struct list_head *this;
struct inode_entry *ie;
list_for_each(this, ilist) {
ie = list_entry(this, struct inode_entry, list);
if (ie->inode->i_ino == ino)
return ie->inode;
}
return NULL;
}
static void add_gc_inode(struct inode *inode, struct list_head *ilist)
{
struct list_head *this;
struct inode_entry *new_ie, *ie;
list_for_each(this, ilist) {
ie = list_entry(this, struct inode_entry, list);
if (ie->inode == inode) {
iput(inode);
return;
}
}
repeat:
new_ie = kmem_cache_alloc(winode_slab, GFP_NOFS);
if (!new_ie) {
cond_resched();
goto repeat;
}
new_ie->inode = inode;
list_add_tail(&new_ie->list, ilist);
}
static void put_gc_inode(struct list_head *ilist)
{
struct inode_entry *ie, *next_ie;
list_for_each_entry_safe(ie, next_ie, ilist, list) {
iput(ie->inode);
list_del(&ie->list);
kmem_cache_free(winode_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;
mutex_lock(&sit_i->sentry_lock);
sentry = get_seg_entry(sbi, segno);
ret = f2fs_test_bit(offset, sentry->cur_valid_map);
mutex_unlock(&sit_i->sentry_lock);
return ret ? GC_OK : GC_NEXT;
}
/*
* 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)
{
bool initial = true;
struct f2fs_summary *entry;
int off;
next_step:
entry = sum;
for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
nid_t nid = le32_to_cpu(entry->nid);
struct page *node_page;
int err;
/*
* It makes sure that free segments are able to write
* all the dirty node pages before CP after this CP.
* So let's check the space of dirty node pages.
*/
if (should_do_checkpoint(sbi)) {
mutex_lock(&sbi->cp_mutex);
block_operations(sbi);
return GC_BLOCKED;
}
err = check_valid_map(sbi, segno, off);
if (err == GC_NEXT)
continue;
if (initial) {
ra_node_page(sbi, nid);
continue;
}
node_page = get_node_page(sbi, nid);
if (IS_ERR(node_page))
continue;
/* set page dirty and write it */
if (!PageWriteback(node_page))
set_page_dirty(node_page);
f2fs_put_page(node_page, 1);
stat_inc_node_blk_count(sbi, 1);
}
if (initial) {
initial = false;
goto next_step;
}
if (gc_type == FG_GC) {
struct writeback_control wbc = {
.sync_mode = WB_SYNC_ALL,
.nr_to_write = LONG_MAX,
.for_reclaim = 0,
};
sync_node_pages(sbi, 0, &wbc);
}
return GC_DONE;
}
/*
* Calculate start block index indicating the given node offset.
* Be careful, caller should give this node offset only indicating direct node
* blocks. If any node offsets, which point the other types of node blocks such
* as indirect or double indirect node blocks, are given, it must be a caller's
* bug.
*/
block_t start_bidx_of_node(unsigned int node_ofs)
{
unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
unsigned int bidx;
if (node_ofs == 0)
return 0;
if (node_ofs <= 2) {
bidx = node_ofs - 1;
} else if (node_ofs <= indirect_blks) {
int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
bidx = node_ofs - 2 - dec;
} else {
int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
bidx = node_ofs - 5 - dec;
}
return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE;
}
static int check_dnode(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
struct node_info *dni, block_t blkaddr, unsigned int *nofs)
{
struct page *node_page;
nid_t nid;
unsigned int ofs_in_node;
block_t source_blkaddr;
nid = le32_to_cpu(sum->nid);
ofs_in_node = le16_to_cpu(sum->ofs_in_node);
node_page = get_node_page(sbi, nid);
if (IS_ERR(node_page))
return GC_NEXT;
get_node_info(sbi, nid, dni);
if (sum->version != dni->version) {
f2fs_put_page(node_page, 1);
return GC_NEXT;
}
*nofs = ofs_of_node(node_page);
source_blkaddr = datablock_addr(node_page, ofs_in_node);
f2fs_put_page(node_page, 1);
if (source_blkaddr != blkaddr)
return GC_NEXT;
return GC_OK;
}
static void move_data_page(struct inode *inode, struct page *page, int gc_type)
{
if (page->mapping != inode->i_mapping)
goto out;
if (inode != page->mapping->host)
goto out;
if (PageWriteback(page))
goto out;
if (gc_type == BG_GC) {
set_page_dirty(page);
set_cold_data(page);
} else {
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
mutex_lock_op(sbi, DATA_WRITE);
if (clear_page_dirty_for_io(page) &&
S_ISDIR(inode->i_mode)) {
dec_page_count(sbi, F2FS_DIRTY_DENTS);
inode_dec_dirty_dents(inode);
}
set_cold_data(page);
do_write_data_page(page);
mutex_unlock_op(sbi, DATA_WRITE);
clear_cold_data(page);
}
out:
f2fs_put_page(page, 1);
}
/*
* This function tries to get parent node of victim data block, and identifies
* data block validity. If the block is valid, copy that with cold status and
* modify parent node.
* If the parent node is not valid or the data block address is different,
* the victim data block is ignored.
*/
static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
struct list_head *ilist, unsigned int segno, int gc_type)
{
struct super_block *sb = sbi->sb;
struct f2fs_summary *entry;
block_t start_addr;
int err, off;
int phase = 0;
start_addr = START_BLOCK(sbi, segno);
next_step:
entry = sum;
for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
struct page *data_page;
struct inode *inode;
struct node_info dni; /* dnode info for the data */
unsigned int ofs_in_node, nofs;
block_t start_bidx;
/*
* It makes sure that free segments are able to write
* all the dirty node pages before CP after this CP.
* So let's check the space of dirty node pages.
*/
if (should_do_checkpoint(sbi)) {
mutex_lock(&sbi->cp_mutex);
block_operations(sbi);
err = GC_BLOCKED;
goto stop;
}
err = check_valid_map(sbi, segno, off);
if (err == GC_NEXT)
continue;
if (phase == 0) {
ra_node_page(sbi, le32_to_cpu(entry->nid));
continue;
}
/* Get an inode by ino with checking validity */
err = check_dnode(sbi, entry, &dni, start_addr + off, &nofs);
if (err == GC_NEXT)
continue;
if (phase == 1) {
ra_node_page(sbi, dni.ino);
continue;
}
start_bidx = start_bidx_of_node(nofs);
ofs_in_node = le16_to_cpu(entry->ofs_in_node);
if (phase == 2) {
inode = f2fs_iget(sb, dni.ino);
if (IS_ERR(inode))
continue;
data_page = find_data_page(inode,
start_bidx + ofs_in_node);
if (IS_ERR(data_page))
goto next_iput;
f2fs_put_page(data_page, 0);
add_gc_inode(inode, ilist);
} else {
inode = find_gc_inode(dni.ino, ilist);
if (inode) {
data_page = get_lock_data_page(inode,
start_bidx + ofs_in_node);
if (IS_ERR(data_page))
continue;
move_data_page(inode, data_page, gc_type);
stat_inc_data_blk_count(sbi, 1);
}
}
continue;
next_iput:
iput(inode);
}
if (++phase < 4)
goto next_step;
err = GC_DONE;
stop:
if (gc_type == FG_GC)
f2fs_submit_bio(sbi, DATA, true);
return err;
}
static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
int gc_type, int type)
{
struct sit_info *sit_i = SIT_I(sbi);
int ret;
mutex_lock(&sit_i->sentry_lock);
ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type, type, LFS);
mutex_unlock(&sit_i->sentry_lock);
return ret;
}
static int do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
struct list_head *ilist, int gc_type)
{
struct page *sum_page;
struct f2fs_summary_block *sum;
int ret = GC_DONE;
/* read segment summary of victim */
sum_page = get_sum_page(sbi, segno);
if (IS_ERR(sum_page))
return GC_ERROR;
/*
* CP needs to lock sum_page. In this time, we don't need
* to lock this page, because this summary page is not gone anywhere.
* Also, this page is not gonna be updated before GC is done.
*/
unlock_page(sum_page);
sum = page_address(sum_page);
switch (GET_SUM_TYPE((&sum->footer))) {
case SUM_TYPE_NODE:
ret = gc_node_segment(sbi, sum->entries, segno, gc_type);
break;
case SUM_TYPE_DATA:
ret = gc_data_segment(sbi, sum->entries, ilist, segno, gc_type);
break;
}
stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)));
stat_inc_call_count(sbi->stat_info);
f2fs_put_page(sum_page, 0);
return ret;
}
int f2fs_gc(struct f2fs_sb_info *sbi)
{
struct list_head ilist;
unsigned int segno, i;
int gc_type = BG_GC;
int gc_status = GC_NONE;
INIT_LIST_HEAD(&ilist);
gc_more:
if (!(sbi->sb->s_flags & MS_ACTIVE))
goto stop;
if (gc_type == BG_GC && has_not_enough_free_secs(sbi))
gc_type = FG_GC;
if (!__get_victim(sbi, &segno, gc_type, NO_CHECK_TYPE))
goto stop;
for (i = 0; i < sbi->segs_per_sec; i++) {
/*
* do_garbage_collect will give us three gc_status:
* GC_ERROR, GC_DONE, and GC_BLOCKED.
* If GC is finished uncleanly, we have to return
* the victim to dirty segment list.
*/
gc_status = do_garbage_collect(sbi, segno + i, &ilist, gc_type);
if (gc_status != GC_DONE)
break;
}
if (has_not_enough_free_secs(sbi)) {
write_checkpoint(sbi, (gc_status == GC_BLOCKED), false);
if (has_not_enough_free_secs(sbi))
goto gc_more;
}
stop:
mutex_unlock(&sbi->gc_mutex);
put_gc_inode(&ilist);
return gc_status;
}
void build_gc_manager(struct f2fs_sb_info *sbi)
{
DIRTY_I(sbi)->v_ops = &default_v_ops;
}
int __init create_gc_caches(void)
{
winode_slab = f2fs_kmem_cache_create("f2fs_gc_inodes",
sizeof(struct inode_entry), NULL);
if (!winode_slab)
return -ENOMEM;
return 0;
}
void destroy_gc_caches(void)
{
kmem_cache_destroy(winode_slab);
}