Re: [f2fs-dev] [PATCH 1/6] f2fs: support issuing/waiting discard in range

From: Chao Yu
Date: Tue Oct 03 2017 - 20:48:53 EST

Hi Jaegeuk,

On 2017/10/4 4:52, Jaegeuk Kim wrote:
> Hi Chao,
>
> Could you please rebase the following patches on top of dev-test?
>
> f2fs-support-issuing-waiting-discard-in-range
> f2fs-wrap-discard-policy
> f2fs-split-discard-policy
> f2fs-reduce-cmd_lock-coverage-in-__issue_discard_cmd
> f2fs-trace-f2fs_remove_discard
> f2fs-give-up-CP_TRIMMED_FLAG-if-it-drops-discards
>
> It seems we need to rearrange some of patches for better review.

No problem, let me rebase them. :)

Thanks,

>
> Thanks,
>
> On 10/03, Jaegeuk Kim wrote:
>> On 09/19, Chao Yu wrote:
>>> From: Chao Yu <yuchao0@xxxxxxxxxx>
>>>
>>> Fstrim intends to trim invalid blocks of filesystem only with specified
>>> range and granularity, but actually, it will issue all previous cached
>>> discard commands which may be out-of-range and be with unmatched
>>> granularity, it's unneeded.
>>>
>>> In order to fix above issues, this patch introduces new helps to support
>>> to issue and wait discard in range and adds a new fstrim_list for tracking
>>> in-flight discard from ->fstrim.
>>>
>>> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
>>> ---
>>> fs/f2fs/f2fs.h | 1 +
>>> fs/f2fs/segment.c | 125 +++++++++++++++++++++++++++++++++++++++++++++---------
>>> 2 files changed, 106 insertions(+), 20 deletions(-)
>>>
>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>> index 89b4927dcd79..cb13c7df6971 100644
>>> --- a/fs/f2fs/f2fs.h
>>> +++ b/fs/f2fs/f2fs.h
>>> @@ -249,6 +249,7 @@ struct discard_cmd_control {
>>> struct list_head pend_list[MAX_PLIST_NUM];/* store pending entries */
>>> unsigned char pend_list_tag[MAX_PLIST_NUM];/* tag for pending entries */
>>> struct list_head wait_list; /* store on-flushing entries */
>>> + struct list_head fstrim_list; /* in-flight discard from fstrim */
>>> wait_queue_head_t discard_wait_queue; /* waiting queue for wake-up */
>>> unsigned int discard_wake; /* to wake up discard thread */
>>> struct mutex cmd_lock;
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index dedf0209d820..088936c61905 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -845,9 +845,11 @@ void __check_sit_bitmap(struct f2fs_sb_info *sbi,
>>>
>>> /* this function is copied from blkdev_issue_discard from block/blk-lib.c */
>>> static void __submit_discard_cmd(struct f2fs_sb_info *sbi,
>>> - struct discard_cmd *dc)
>>> + struct discard_cmd *dc, bool fstrim)
>>> {
>>> struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
>>> + struct list_head *wait_list = fstrim ? &(dcc->fstrim_list) :
>>> + &(dcc->wait_list);
>>> struct bio *bio = NULL;
>>>
>>> if (dc->state != D_PREP)
>>> @@ -869,7 +871,7 @@ static void __submit_discard_cmd(struct f2fs_sb_info *sbi,
>>> bio->bi_end_io = f2fs_submit_discard_endio;
>>> bio->bi_opf |= REQ_SYNC;
>>> submit_bio(bio);
>>> - list_move_tail(&dc->list, &dcc->wait_list);
>>> + list_move_tail(&dc->list, wait_list);
>>> __check_sit_bitmap(sbi, dc->start, dc->start + dc->len);
>>>
>>> f2fs_update_iostat(sbi, FS_DISCARD, 1);
>>> @@ -1054,6 +1056,68 @@ static int __queue_discard_cmd(struct f2fs_sb_info *sbi,
>>> return 0;
>>> }
>>>
>>> +static void __issue_discard_cmd_range(struct f2fs_sb_info *sbi,
>>> + unsigned int start, unsigned int end,
>>> + unsigned int granularity)
>>> +{
>>> + struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
>>> + struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
>>> + struct rb_node **insert_p = NULL, *insert_parent = NULL;
>>> + struct discard_cmd *dc;
>>> + struct blk_plug plug;
>>> + int issued;
>>> +
>>> +next:
>>> + issued = 0;
>>> +
>>> + mutex_lock(&dcc->cmd_lock);
>>> + f2fs_bug_on(sbi, !__check_rb_tree_consistence(sbi, &dcc->root));
>>> +
>>> + dc = (struct discard_cmd *)__lookup_rb_tree_ret(&dcc->root,
>>> + NULL, start,
>>> + (struct rb_entry **)&prev_dc,
>>> + (struct rb_entry **)&next_dc,
>>> + &insert_p, &insert_parent, true);
>>> + if (!dc)
>>> + dc = next_dc;
>>> +
>>> + blk_start_plug(&plug);
>>> +
>>> + while (dc && dc->lstart <= end) {
>>> + struct rb_node *node;
>>> +
>>> + if (dc->len < granularity)
>>> + goto skip;
>>> +
>>> + if (dc->state != D_PREP) {
>>> + list_move_tail(&dc->list, &dcc->fstrim_list);
>>> + goto skip;
>>> + }
>>> +
>>> + __submit_discard_cmd(sbi, dc, true);
>>> +
>>> + if (++issued >= DISCARD_ISSUE_RATE) {
>>> + start = dc->lstart + dc->len;
>>> +
>>> + blk_finish_plug(&plug);
>>> + mutex_unlock(&dcc->cmd_lock);
>>> +
>>> + schedule();
>>> +
>>> + goto next;
>>> + }
>>> +skip:
>>> + node = rb_next(&dc->rb_node);
>>> + dc = rb_entry_safe(node, struct discard_cmd, rb_node);
>>> +
>>> + if (fatal_signal_pending(current))
>>> + break;
>>> + }
>>> +
>>> + blk_finish_plug(&plug);
>>> + mutex_unlock(&dcc->cmd_lock);
>>> +}
>>> +
>>> static int __issue_discard_cmd(struct f2fs_sb_info *sbi, bool issue_cond)
>>> {
>>> struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
>>> @@ -1076,22 +1140,19 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi, bool issue_cond)
>>>
>>> /* Hurry up to finish fstrim */
>>> if (dcc->pend_list_tag[i] & P_TRIM) {
>>> - __submit_discard_cmd(sbi, dc);
>>> + __submit_discard_cmd(sbi, dc, false);
>>> issued++;
>>> -
>>> - if (fatal_signal_pending(current))
>>> - break;
>>> continue;
>>> }
>>>
>>> if (!issue_cond) {
>>> - __submit_discard_cmd(sbi, dc);
>>> + __submit_discard_cmd(sbi, dc, false);
>>> issued++;
>>> continue;
>>> }
>>>
>>> if (is_idle(sbi)) {
>>> - __submit_discard_cmd(sbi, dc);
>>> + __submit_discard_cmd(sbi, dc, false);
>>> issued++;
>>> } else {
>>> io_interrupted = true;
>>> @@ -1145,10 +1206,14 @@ static void __wait_one_discard_bio(struct f2fs_sb_info *sbi,
>>> mutex_unlock(&dcc->cmd_lock);
>>> }
>>>
>>> -static void __wait_discard_cmd(struct f2fs_sb_info *sbi, bool wait_cond)
>>> +static void __wait_discard_cmd_range(struct f2fs_sb_info *sbi, bool wait_cond,
>>> + block_t start, block_t end,
>>> + unsigned int granularity,
>>> + bool fstrim)
>>> {
>>> struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
>>> - struct list_head *wait_list = &(dcc->wait_list);
>>> + struct list_head *wait_list = fstrim ? &(dcc->fstrim_list) :
>>> + &(dcc->wait_list);
>>> struct discard_cmd *dc, *tmp;
>>> bool need_wait;
>>>
>>> @@ -1157,6 +1222,10 @@ static void __wait_discard_cmd(struct f2fs_sb_info *sbi, bool wait_cond)
>>>
>>> mutex_lock(&dcc->cmd_lock);
>>> list_for_each_entry_safe(dc, tmp, wait_list, list) {
>>> + if (dc->lstart + dc->len <= start || end <= dc->lstart)
>>> + continue;
>>> + if (dc->len < granularity)
>>> + continue;
>>> if (!wait_cond || (dc->state == D_DONE && !dc->ref)) {
>>> wait_for_completion_io(&dc->wait);
>>> __remove_discard_cmd(sbi, dc);
>>
>> So, we need to add this on top of the patch that fixes the bug reported
>> by Juhyung, right?
>>
>> if (fstrim)
>> need_wait = true;
>>
>> Thanks,
>>
>>> @@ -1174,6 +1243,11 @@ static void __wait_discard_cmd(struct f2fs_sb_info *sbi, bool wait_cond)
>>> }
>>> }
>>>
>>> +static void __wait_all_discard_cmd(struct f2fs_sb_info *sbi, bool wait_cond)
>>> +{
>>> + __wait_discard_cmd_range(sbi, wait_cond, 0, UINT_MAX, 1, false);
>>> +}
>>> +
>>> /* This should be covered by global mutex, &sit_i->sentry_lock */
>>> void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
>>> {
>>> @@ -1209,12 +1283,12 @@ void stop_discard_thread(struct f2fs_sb_info *sbi)
>>> }
>>> }
>>>
>>> -/* This comes from f2fs_put_super and f2fs_trim_fs */
>>> +/* This comes from f2fs_put_super */
>>> void f2fs_wait_discard_bios(struct f2fs_sb_info *sbi)
>>> {
>>> __issue_discard_cmd(sbi, false);
>>> __drop_discard_cmd(sbi);
>>> - __wait_discard_cmd(sbi, false);
>>> + __wait_all_discard_cmd(sbi, false);
>>> }
>>>
>>> static void mark_discard_range_all(struct f2fs_sb_info *sbi)
>>> @@ -1258,7 +1332,7 @@ static int issue_discard_thread(void *data)
>>>
>>> issued = __issue_discard_cmd(sbi, true);
>>> if (issued) {
>>> - __wait_discard_cmd(sbi, true);
>>> + __wait_all_discard_cmd(sbi, true);
>>> wait_ms = DEF_MIN_DISCARD_ISSUE_TIME;
>>> } else {
>>> wait_ms = DEF_MAX_DISCARD_ISSUE_TIME;
>>> @@ -1569,6 +1643,7 @@ static int create_discard_cmd_control(struct f2fs_sb_info *sbi)
>>> dcc->pend_list_tag[i] |= P_ACTIVE;
>>> }
>>> INIT_LIST_HEAD(&dcc->wait_list);
>>> + INIT_LIST_HEAD(&dcc->fstrim_list);
>>> mutex_init(&dcc->cmd_lock);
>>> atomic_set(&dcc->issued_discard, 0);
>>> atomic_set(&dcc->issing_discard, 0);
>>> @@ -2196,7 +2271,8 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
>>> {
>>> __u64 start = F2FS_BYTES_TO_BLK(range->start);
>>> __u64 end = start + F2FS_BYTES_TO_BLK(range->len) - 1;
>>> - unsigned int start_segno, end_segno;
>>> + unsigned int start_segno, end_segno, cur_segno;
>>> + block_t start_block, end_block;
>>> struct cp_control cpc;
>>> int err = 0;
>>>
>>> @@ -2217,12 +2293,17 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
>>> start_segno = (start <= MAIN_BLKADDR(sbi)) ? 0 : GET_SEGNO(sbi, start);
>>> end_segno = (end >= MAX_BLKADDR(sbi)) ? MAIN_SEGS(sbi) - 1 :
>>> GET_SEGNO(sbi, end);
>>> +
>>> + start_block = START_BLOCK(sbi, start_segno);
>>> + end_block = START_BLOCK(sbi, end_segno + 1);
>>> +
>>> cpc.reason = CP_DISCARD;
>>> cpc.trim_minlen = max_t(__u64, 1, F2FS_BYTES_TO_BLK(range->minlen));
>>>
>>> /* do checkpoint to issue discard commands safely */
>>> - for (; start_segno <= end_segno; start_segno = cpc.trim_end + 1) {
>>> - cpc.trim_start = start_segno;
>>> + for (cur_segno = start_segno; cur_segno <= end_segno;
>>> + cur_segno = cpc.trim_end + 1) {
>>> + cpc.trim_start = cur_segno;
>>>
>>> if (sbi->discard_blks == 0)
>>> break;
>>> @@ -2230,7 +2311,7 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
>>> cpc.trim_end = end_segno;
>>> else
>>> cpc.trim_end = min_t(unsigned int,
>>> - rounddown(start_segno +
>>> + rounddown(cur_segno +
>>> BATCHED_TRIM_SEGMENTS(sbi),
>>> sbi->segs_per_sec) - 1, end_segno);
>>>
>>> @@ -2242,9 +2323,13 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
>>>
>>> schedule();
>>> }
>>> - /* It's time to issue all the filed discards */
>>> - mark_discard_range_all(sbi);
>>> - f2fs_wait_discard_bios(sbi);
>>> +
>>> + start_block = START_BLOCK(sbi, start_segno);
>>> + end_block = START_BLOCK(sbi, min(cur_segno, end_segno) + 1);
>>> +
>>> + __issue_discard_cmd_range(sbi, start_block, end_block, cpc.trim_minlen);
>>> + __wait_discard_cmd_range(sbi, false, start_block, end_block,
>>> + cpc.trim_minlen, true);
>>> out:
>>> range->len = F2FS_BLK_TO_BYTES(cpc.trimmed);
>>> return err;
>>> --
>>> 2.14.1.145.gb3622a4ee
>
> ------------------------------------------------------------------------------
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
>