Re: [PATCH] f2fs: don't wait writeback for datas during checkpoint

From: Chao Yu
Date: Mon Nov 14 2016 - 06:19:32 EST

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In reply to: Jaegeuk Kim: "Re: [PATCH] f2fs: don't wait writeback for datas during checkpoint"
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Hi Jaegeuk,

On 2016/11/11 4:03, Jaegeuk Kim wrote:
> Hi Chao,
>
> On Thu, Nov 10, 2016 at 07:40:03PM +0800, Chao Yu wrote:
>> Normally, while committing checkpoint, we will wait on all pages to be
>> writebacked no matter the page is data or metadata, so in scenario where
>> there are lots of data IO being submitted with metadata, we may suffer
>> long latency for waiting writeback during checkpoint.
>>
>> Indeed, we only care about persistence for pages with metadata, but not
>> pages with data, as file system consistent are only related to metadate,
>> so in order to avoid encountering long latency in above scenario, let's
>> recognize and reference metadata in submitted IOs, wait writeback only
>> for metadatas.
>>
>> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
>> ---
>> fs/f2fs/checkpoint.c | 2 +-
>> fs/f2fs/data.c | 9 +++++++--
>> fs/f2fs/debug.c | 7 ++++---
>> fs/f2fs/f2fs.h | 26 +++++++++++++++++++++++---
>> fs/f2fs/gc.c | 2 ++
>> fs/f2fs/node.c | 1 +
>> fs/f2fs/segment.c | 2 ++
>> 7 files changed, 40 insertions(+), 9 deletions(-)
>>
>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
>> index 7bece59..bdf8a50 100644
>> --- a/fs/f2fs/checkpoint.c
>> +++ b/fs/f2fs/checkpoint.c
>> @@ -1003,7 +1003,7 @@ static void wait_on_all_pages_writeback(struct f2fs_sb_info *sbi)
>> for (;;) {
>> prepare_to_wait(&sbi->cp_wait, &wait, TASK_UNINTERRUPTIBLE);
>>
>> - if (!atomic_read(&sbi->nr_wb_bios))
>> + if (!get_pages(sbi, F2FS_WB_META))
>> break;
>>
>> io_schedule_timeout(5*HZ);
>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>> index 66d2aee..2fb1ffd 100644
>> --- a/fs/f2fs/data.c
>> +++ b/fs/f2fs/data.c
>> @@ -73,6 +73,7 @@ static void f2fs_write_end_io(struct bio *bio)
>>
>> bio_for_each_segment_all(bvec, bio, i) {
>> struct page *page = bvec->bv_page;
>> + bool is_meta = f2fs_is_meta_data(page);
>>
>> fscrypt_pullback_bio_page(&page, true);
>>
>> @@ -80,9 +81,10 @@ static void f2fs_write_end_io(struct bio *bio)
>> mapping_set_error(page->mapping, -EIO);
>> f2fs_stop_checkpoint(sbi, true);
>> }
>> + dec_page_count(sbi, is_meta ? F2FS_WB_META : F2FS_WB_DATA);
>> end_page_writeback(page);
>> }
>> - if (atomic_dec_and_test(&sbi->nr_wb_bios) &&
>> + if (!get_pages(sbi, F2FS_WB_META) &&
>> wq_has_sleeper(&sbi->cp_wait))
>> wake_up(&sbi->cp_wait);
>>
>> @@ -111,7 +113,6 @@ static inline void __submit_bio(struct f2fs_sb_info *sbi,
>> struct bio *bio, enum page_type type)
>> {
>> if (!is_read_io(bio_op(bio))) {
>> - atomic_inc(&sbi->nr_wb_bios);
>> if (f2fs_sb_mounted_blkzoned(sbi->sb) &&
>> current->plug && (type == DATA || type == NODE))
>> blk_finish_plug(current->plug);
>> @@ -272,6 +273,9 @@ void f2fs_submit_page_mbio(struct f2fs_io_info *fio)
>> verify_block_addr(sbi, fio->old_blkaddr);
>> verify_block_addr(sbi, fio->new_blkaddr);
>>
>> + if (!is_read)
>> + inc_page_count(sbi, fio->is_meta ? F2FS_WB_META : F2FS_WB_DATA);
>> +
>
> How about using f2fs_is_meta_data(page) instead of changing fio?

Yes, I've cleaned up codes as you mentioned, and also fix incorrectly handling
of GCed encrypted datas. Could you please review the following v2 patch?

Thanks,

>
> Thanks,
>
>> down_write(&io->io_rwsem);
>>
>> if (io->bio && (io->last_block_in_bio != fio->new_blkaddr - 1 ||
>> @@ -1237,6 +1241,7 @@ static int f2fs_write_data_page(struct page *page,
>> .type = DATA,
>> .op = REQ_OP_WRITE,
>> .op_flags = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : 0,
>> + .is_meta = S_ISDIR(inode->i_mode),
>> .page = page,
>> .encrypted_page = NULL,
>> };
>> diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
>> index 2fdf233..f2d87de 100644
>> --- a/fs/f2fs/debug.c
>> +++ b/fs/f2fs/debug.c
>> @@ -50,7 +50,8 @@ static void update_general_status(struct f2fs_sb_info *sbi)
>> si->ndirty_files = sbi->ndirty_inode[FILE_INODE];
>> si->ndirty_all = sbi->ndirty_inode[DIRTY_META];
>> si->inmem_pages = get_pages(sbi, F2FS_INMEM_PAGES);
>> - si->wb_bios = atomic_read(&sbi->nr_wb_bios);
>> + si->nr_wb_meta = get_pages(sbi, F2FS_WB_META);
>> + si->nr_wb_data = get_pages(sbi, F2FS_WB_DATA);
>> si->total_count = (int)sbi->user_block_count / sbi->blocks_per_seg;
>> si->rsvd_segs = reserved_segments(sbi);
>> si->overp_segs = overprovision_segments(sbi);
>> @@ -313,8 +314,8 @@ static int stat_show(struct seq_file *s, void *v)
>> seq_printf(s, " - Inner Struct Count: tree: %d(%d), node: %d\n",
>> si->ext_tree, si->zombie_tree, si->ext_node);
>> seq_puts(s, "\nBalancing F2FS Async:\n");
>> - seq_printf(s, " - inmem: %4d, wb_bios: %4d\n",
>> - si->inmem_pages, si->wb_bios);
>> + seq_printf(s, " - inmem: %4d, wb_meta: %4d, wb_data: %4d\n",
>> + si->inmem_pages, si->nr_wb_meta, si->nr_wb_data);
>> seq_printf(s, " - nodes: %4d in %4d\n",
>> si->ndirty_node, si->node_pages);
>> seq_printf(s, " - dents: %4d in dirs:%4d (%4d)\n",
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index 23a937f..95ad091 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -682,6 +682,8 @@ enum count_type {
>> F2FS_DIRTY_META,
>> F2FS_INMEM_PAGES,
>> F2FS_DIRTY_IMETA,
>> + F2FS_WB_META,
>> + F2FS_WB_DATA,
>> NR_COUNT_TYPE,
>> };
>>
>> @@ -715,6 +717,7 @@ struct f2fs_io_info {
>> enum page_type type; /* contains DATA/NODE/META/META_FLUSH */
>> int op; /* contains REQ_OP_ */
>> int op_flags; /* rq_flag_bits */
>> + bool is_meta; /* checkpoint needs to wait its writeback */
>> block_t new_blkaddr; /* new block address to be written */
>> block_t old_blkaddr; /* old block address before Cow */
>> struct page *page; /* page to be written */
>> @@ -849,7 +852,6 @@ struct f2fs_sb_info {
>> block_t discard_blks; /* discard command candidats */
>> block_t last_valid_block_count; /* for recovery */
>> u32 s_next_generation; /* for NFS support */
>> - atomic_t nr_wb_bios; /* # of writeback bios */
>>
>> /* # of pages, see count_type */
>> atomic_t nr_pages[NR_COUNT_TYPE];
>> @@ -1193,6 +1195,23 @@ static inline int check_nid_range(struct f2fs_sb_info *sbi, nid_t nid)
>> return 0;
>> }
>>
>> +static inline bool f2fs_is_meta_data(struct page *page)
>> +{
>> + struct address_space *mapping = page->mapping;
>> + struct inode *inode;
>> +
>> + /* it is bounce page of encrypted regular inode */
>> + if (!mapping)
>> + return false;
>> +
>> + inode = mapping->host;
>> + if (inode->i_ino == F2FS_NODE_INO(F2FS_I_SB(inode)) ||
>> + inode->i_ino == F2FS_META_INO(F2FS_I_SB(inode)) ||
>> + S_ISDIR(inode->i_mode))
>> + return true;
>> + return false;
>> +}
>> +
>> #define F2FS_DEFAULT_ALLOCATED_BLOCKS 1
>>
>> /*
>> @@ -1263,7 +1282,8 @@ static inline void inc_page_count(struct f2fs_sb_info *sbi, int count_type)
>> {
>> atomic_inc(&sbi->nr_pages[count_type]);
>>
>> - if (count_type == F2FS_DIRTY_DATA || count_type == F2FS_INMEM_PAGES)
>> + if (count_type == F2FS_DIRTY_DATA || count_type == F2FS_INMEM_PAGES ||
>> + count_type == F2FS_WB_META || count_type == F2FS_WB_DATA)
>> return;
>>
>> set_sbi_flag(sbi, SBI_IS_DIRTY);
>> @@ -2219,7 +2239,7 @@ struct f2fs_stat_info {
>> unsigned int ndirty_dirs, ndirty_files, ndirty_all;
>> int nats, dirty_nats, sits, dirty_sits, free_nids, alloc_nids;
>> int total_count, utilization;
>> - int bg_gc, wb_bios;
>> + int bg_gc, nr_wb_meta, nr_wb_data;
>> int inline_xattr, inline_inode, inline_dir, orphans;
>> unsigned int valid_count, valid_node_count, valid_inode_count, discard_blks;
>> unsigned int bimodal, avg_vblocks;
>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
>> index f8d8cc96a..6b762d4 100644
>> --- a/fs/f2fs/gc.c
>> +++ b/fs/f2fs/gc.c
>> @@ -554,6 +554,7 @@ static void move_encrypted_block(struct inode *inode, block_t bidx,
>> .type = DATA,
>> .op = REQ_OP_READ,
>> .op_flags = READ_SYNC,
>> + .is_meta = true,
>> .encrypted_page = NULL,
>> };
>> struct dnode_of_data dn;
>> @@ -674,6 +675,7 @@ static void move_data_page(struct inode *inode, block_t bidx, int gc_type,
>> .type = DATA,
>> .op = REQ_OP_WRITE,
>> .op_flags = WRITE_SYNC,
>> + .is_meta = S_ISDIR(inode->i_mode),
>> .page = page,
>> .encrypted_page = NULL,
>> };
>> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
>> index d58438f..3c7e00c 100644
>> --- a/fs/f2fs/node.c
>> +++ b/fs/f2fs/node.c
>> @@ -1574,6 +1574,7 @@ static int f2fs_write_node_page(struct page *page,
>> .type = NODE,
>> .op = REQ_OP_WRITE,
>> .op_flags = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : 0,
>> + .is_meta = true,
>> .page = page,
>> .encrypted_page = NULL,
>> };
>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>> index 078c571..b34e20a 100644
>> --- a/fs/f2fs/segment.c
>> +++ b/fs/f2fs/segment.c
>> @@ -261,6 +261,7 @@ static int __commit_inmem_pages(struct inode *inode,
>> .type = DATA,
>> .op = REQ_OP_WRITE,
>> .op_flags = WRITE_SYNC | REQ_PRIO,
>> + .is_meta = false,
>> .encrypted_page = NULL,
>> };
>> bool submit_bio = false;
>> @@ -1573,6 +1574,7 @@ void write_meta_page(struct f2fs_sb_info *sbi, struct page *page)
>> .type = META,
>> .op = REQ_OP_WRITE,
>> .op_flags = WRITE_SYNC | REQ_META | REQ_PRIO,
>> + .is_meta = true,
>> .old_blkaddr = page->index,
>> .new_blkaddr = page->index,
>> .page = page,
>> --
>> 2.8.2.311.gee88674
>
> .
>

Next message: Daniel Lezcano: "Re: [PATCH v5 3/3] clocksource: Add clockevent support to NPS400 driver"
Previous message: Hans Verkuil: "Re: [PATCH v4 1/8] media: adv7180: fix field type"
In reply to: Jaegeuk Kim: "Re: [PATCH] f2fs: don't wait writeback for datas during checkpoint"
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