On 2019/10/26 2:18, Jaegeuk Kim wrote:
> On 10/24, Chao Yu wrote:
>> Hi Jaegeuk,
>>
>> On 2019/10/23 1:16, Jaegeuk Kim wrote:
>>> This patch supports 2MB-aligned pinned file, which can guarantee no GC at
>>> all
>>> by allocating fully valid 2MB segment.
>>>
>>> Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
>>> ---
>>> fs/f2fs/f2fs.h | 4 +++-
>>> fs/f2fs/file.c | 39 ++++++++++++++++++++++++++++++++++-----
>>> fs/f2fs/recovery.c | 2 +-
>>> fs/f2fs/segment.c | 21 ++++++++++++++++++++-
>>> fs/f2fs/segment.h | 2 ++
>>> fs/f2fs/super.c | 1 +
>>> fs/f2fs/sysfs.c | 2 ++
>>> 7 files changed, 63 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>> index ca342f4c7db1..c681f51e351b 100644
>>> --- a/fs/f2fs/f2fs.h
>>> +++ b/fs/f2fs/f2fs.h
>>> @@ -890,6 +890,7 @@ enum {
>>> CURSEG_WARM_NODE, /* direct node blocks of normal files */
>>> CURSEG_COLD_NODE, /* indirect node blocks */
>>> NO_CHECK_TYPE,
>>> + CURSEG_COLD_DATA_PINNED,/* cold data for pinned file */
>>> };
>>>
>>> struct flush_cmd {
>>> @@ -1301,6 +1302,7 @@ struct f2fs_sb_info {
>>>
>>> /* threshold for gc trials on pinned files */
>>> u64 gc_pin_file_threshold;
>>> + struct rw_semaphore pin_sem;
>>>
>>> /* maximum # of trials to find a victim segment for SSR and GC */
>>> unsigned int max_victim_search;
>>> @@ -3116,7 +3118,7 @@ void f2fs_release_discard_addrs(struct f2fs_sb_info
>>> *sbi);
>>> int f2fs_npages_for_summary_flush(struct f2fs_sb_info *sbi, bool for_ra);
>>> void allocate_segment_for_resize(struct f2fs_sb_info *sbi, int type,
>>> unsigned int start, unsigned int end);
>>> -void f2fs_allocate_new_segments(struct f2fs_sb_info *sbi);
>>> +void f2fs_allocate_new_segments(struct f2fs_sb_info *sbi, int type);
>>> int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range);
>>> bool f2fs_exist_trim_candidates(struct f2fs_sb_info *sbi,
>>> struct cp_control *cpc);
>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
>>> index 29bc0a542759..f6c038e8a6a7 100644
>>> --- a/fs/f2fs/file.c
>>> +++ b/fs/f2fs/file.c
>>> @@ -1545,12 +1545,41 @@ static int expand_inode_data(struct inode *inode,
>>> loff_t offset,
>>> if (off_end)
>>> map.m_len++;
>>>
>>> - if (f2fs_is_pinned_file(inode))
>>> - map.m_seg_type = CURSEG_COLD_DATA;
>>> + if (!map.m_len)
>>> + return 0;
>>> +
>>> + if (f2fs_is_pinned_file(inode)) {
>>> + block_t len = (map.m_len >> sbi->log_blocks_per_seg) <<
>>> + sbi->log_blocks_per_seg;
>>> + block_t done = 0;
>>> +
>>> + if (map.m_len % sbi->blocks_per_seg)
>>> + len += sbi->blocks_per_seg;
>>>
>>> - err = f2fs_map_blocks(inode, &map, 1, (f2fs_is_pinned_file(inode) ?
>>> - F2FS_GET_BLOCK_PRE_DIO :
>>> - F2FS_GET_BLOCK_PRE_AIO));
>>> + map.m_len = sbi->blocks_per_seg;
>>> +next_alloc:
>>> + mutex_lock(&sbi->gc_mutex);
>>> + err = f2fs_gc(sbi, true, false, NULL_SEGNO);
>>> + if (err && err != -ENODATA && err != -EAGAIN)
>>> + goto out_err;
>>
>> To grab enough free space?
>>
>> Shouldn't we call
>>
>> if (has_not_enough_free_secs(sbi, 0, 0)) {
>> mutex_lock(&sbi->gc_mutex);
>> f2fs_gc(sbi, false, false, NULL_SEGNO);
>> }
>
> The above calls gc all the time. Do we need this?
Hmmm... my concern is why we need to run foreground GC even if there is enough
free space..
>
>>
>>> +
>>> + down_write(&sbi->pin_sem);
>>> + map.m_seg_type = CURSEG_COLD_DATA_PINNED;
>>> + f2fs_allocate_new_segments(sbi, CURSEG_COLD_DATA);
>>> + err = f2fs_map_blocks(inode, &map, 1, F2FS_GET_BLOCK_PRE_DIO);
>>> + up_write(&sbi->pin_sem);
>>> +
>>> + done += map.m_len;
>>> + len -= map.m_len;
>>> + map.m_lblk += map.m_len;
>>> + if (!err && len)
>>> + goto next_alloc;
>>> +
>>> + map.m_len = done;
>>> + } else {
>>> + err = f2fs_map_blocks(inode, &map, 1, F2FS_GET_BLOCK_PRE_AIO);
>>> + }
>>> +out_err:
>>> if (err) {
>>> pgoff_t last_off;
>>>
>>> diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
>>> index 783773e4560d..76477f71d4ee 100644
>>> --- a/fs/f2fs/recovery.c
>>> +++ b/fs/f2fs/recovery.c
>>> @@ -711,7 +711,7 @@ static int recover_data(struct f2fs_sb_info *sbi,
>>> struct list_head *inode_list,
>>> f2fs_put_page(page, 1);
>>> }
>>> if (!err)
>>> - f2fs_allocate_new_segments(sbi);
>>> + f2fs_allocate_new_segments(sbi, NO_CHECK_TYPE);
>>> return err;
>>> }
>>>
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index 25c750cd0272..253d72c2663c 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -2690,7 +2690,7 @@ void allocate_segment_for_resize(struct f2fs_sb_info
>>> *sbi, int type,
>>> up_read(&SM_I(sbi)->curseg_lock);
>>> }
>>>
>>> -void f2fs_allocate_new_segments(struct f2fs_sb_info *sbi)
>>> +void f2fs_allocate_new_segments(struct f2fs_sb_info *sbi, int type)
>>> {
>>> struct curseg_info *curseg;
>>> unsigned int old_segno;
>>> @@ -2699,6 +2699,9 @@ void f2fs_allocate_new_segments(struct f2fs_sb_info
>>> *sbi)
>>> down_write(&SIT_I(sbi)->sentry_lock);
>>>
>>> for (i = CURSEG_HOT_DATA; i <= CURSEG_COLD_DATA; i++) {
>>> + if (type != NO_CHECK_TYPE && i != type)
>>> + continue;
>>> +
>>> curseg = CURSEG_I(sbi, i);
>>> old_segno = curseg->segno;
>>> SIT_I(sbi)->s_ops->allocate_segment(sbi, i, true);
>>> @@ -3068,6 +3071,19 @@ void f2fs_allocate_data_block(struct f2fs_sb_info
>>> *sbi, struct page *page,
>>> {
>>> struct sit_info *sit_i = SIT_I(sbi);
>>> struct curseg_info *curseg = CURSEG_I(sbi, type);
>>> + bool put_pin_sem = false;
>>> +
>>> + if (type == CURSEG_COLD_DATA) {
>>> + /* GC during CURSEG_COLD_DATA_PINNED allocation */
>>> + if (down_read_trylock(&sbi->pin_sem)) {
>>> + put_pin_sem = true;
>>> + } else {
>>> + type = CURSEG_WARM_DATA;
>>> + curseg = CURSEG_I(sbi, type);
>>
>> It will mix pending cold data into warm area... rather than recovering
>> curseg to
>> write pointer of last cold segment?
>>
>> I know maybe that fallocate aligned address could be corner case, but I guess
>> there should be some better solutions can handle race case more effectively.
>>
>> One solution could be: allocating a virtual log header to select free
>> segment as
>> 2m-aligned space target.
>
> I thought about that, but concluded to avoid too much changes.
We have an unupstreamed feature which is based on virtual log header, I can
introduce that basic virtual log fwk, which can be used for aligned allocation
and later new features, would you like to check that?
Thanks,
>
>>
>> Thanks,
>>
>>> + }
>>> + } else if (type == CURSEG_COLD_DATA_PINNED) {
>>> + type = CURSEG_COLD_DATA;
>>> + }
>>>
>>> down_read(&SM_I(sbi)->curseg_lock);
>>>
>>> @@ -3133,6 +3149,9 @@ void f2fs_allocate_data_block(struct f2fs_sb_info
>>> *sbi, struct page *page,
>>> mutex_unlock(&curseg->curseg_mutex);
>>>
>>> up_read(&SM_I(sbi)->curseg_lock);
>>> +
>>> + if (put_pin_sem)
>>> + up_read(&sbi->pin_sem);
>>> }
>>>
>>> static void update_device_state(struct f2fs_io_info *fio)
>>> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
>>> index 325781a1ae4d..a95467b202ea 100644
>>> --- a/fs/f2fs/segment.h
>>> +++ b/fs/f2fs/segment.h
>>> @@ -313,6 +313,8 @@ struct sit_entry_set {
>>> */
>>> static inline struct curseg_info *CURSEG_I(struct f2fs_sb_info *sbi, int
>>> type)
>>> {
>>> + if (type == CURSEG_COLD_DATA_PINNED)
>>> + type = CURSEG_COLD_DATA;
>>> return (struct curseg_info *)(SM_I(sbi)->curseg_array + type);
>>> }
>>>
>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>> index f320fd11db48..c02a47ce551b 100644
>>> --- a/fs/f2fs/super.c
>>> +++ b/fs/f2fs/super.c
>>> @@ -2853,6 +2853,7 @@ static void init_sb_info(struct f2fs_sb_info *sbi)
>>> spin_lock_init(&sbi->dev_lock);
>>>
>>> init_rwsem(&sbi->sb_lock);
>>> + init_rwsem(&sbi->pin_sem);
>>> }
>>>
>>> static int init_percpu_info(struct f2fs_sb_info *sbi)
>>> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
>>> index b558b64a4c9c..f164959e4224 100644
>>> --- a/fs/f2fs/sysfs.c
>>> +++ b/fs/f2fs/sysfs.c
>>> @@ -154,6 +154,8 @@ static ssize_t features_show(struct f2fs_attr *a,
>>> if (f2fs_sb_has_casefold(sbi))
>>> len += snprintf(buf + len, PAGE_SIZE - len, "%s%s",
>>> len ? ", " : "", "casefold");
>>> + len += snprintf(buf + len, PAGE_SIZE - len, "%s%s",
>>> + len ? ", " : "", "pin_file");
>>> len += snprintf(buf + len, PAGE_SIZE - len, "\n");
>>> return len;
>>> }
>>>
> .
>
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