Re: [f2fs-dev] [PATCH 1/3] f2fs: support passing down write hints given by users to block layer

From: Hyunchul Lee
Date: Wed Jan 24 2018 - 21:47:28 EST


Hi Chao,

On 01/25/2018 12:32 AM, Chao Yu wrote:
> On 2018/1/22 18:49, Hyunchul Lee wrote:
>> From: Hyunchul Lee <cheol.lee@xxxxxxx>
>>
>> Add the 'whint_mode' mount option that controls which write
>> hints are passed down to block layer. There are "off" and
>> "user-based" mode. The default mode is "off".
>>
>> 1) whint_mode=user-based. F2FS tries to pass down hints given
>> by users.
>
> Minor,
>
> 1) whint_mode=off. F2FS only passes down WRITE_LIFE_NOT_SET
>
> 2) whint_mode=user-based. F2FS tries to pass down hints given by users.
> ...
>

Okay, I will reflect this.

> How about changing all comments and codes with above order?
>
>>
>> User F2FS Block
>> ---- ---- -----
>> META WRITE_LIFE_NOT_SET
>> HOT_NODE "
>> WARM_NODE "
>> COLD_NODE "
>> ioctl(COLD) COLD_DATA WRITE_LIFE_EXTREME
>> extension list " "
>>
>> -- buffered io
>> WRITE_LIFE_EXTREME COLD_DATA WRITE_LIFE_EXTREME
>> WRITE_LIFE_SHORT HOT_DATA WRITE_LIFE_SHORT
>> WRITE_LIFE_NOT_SET WARM_DATA WRITE_LIFE_NOT_SET
>> WRITE_LIFE_NONE " "
>> WRITE_LIFE_MEDIUM " "
>> WRITE_LIFE_LONG " "
>>
>> -- direct io
>> WRITE_LIFE_EXTREME COLD_DATA WRITE_LIFE_EXTREME
>> WRITE_LIFE_SHORT HOT_DATA WRITE_LIFE_SHORT
>> WRITE_LIFE_NOT_SET WARM_DATA WRITE_LIFE_NOT_SET
>> WRITE_LIFE_NONE " WRITE_LIFE_NONE
>> WRITE_LIFE_MEDIUM " WRITE_LIFE_MEDIUM
>> WRITE_LIFE_LONG " WRITE_LIFE_LONG
>>
>> 2) whint_mode=off. F2FS only passes down WRITE_LIFE_NOT_SET.
>>
>> Many thanks to Chao Yu and Jaegeuk Kim for comments to
>> implement this patch.
>>
>> Signed-off-by: Hyunchul Lee <cheol.lee@xxxxxxx>
>> ---
>> fs/f2fs/data.c | 27 ++++++++++++++++++++-----
>> fs/f2fs/f2fs.h | 9 +++++++++
>> fs/f2fs/segment.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> fs/f2fs/super.c | 24 +++++++++++++++++++++-
>> 4 files changed, 113 insertions(+), 6 deletions(-)
>>
>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>> index 6cba74e..c76ddc2 100644
>> --- a/fs/f2fs/data.c
>> +++ b/fs/f2fs/data.c
>> @@ -175,15 +175,22 @@ static bool __same_bdev(struct f2fs_sb_info *sbi,
>> */
>> static struct bio *__bio_alloc(struct f2fs_sb_info *sbi, block_t blk_addr,
>> struct writeback_control *wbc,
>> - int npages, bool is_read)
>> + int npages, bool is_read,
>> + enum page_type type, enum temp_type temp)
>> {
>> struct bio *bio;
>>
>> bio = f2fs_bio_alloc(sbi, npages, true);
>>
>> f2fs_target_device(sbi, blk_addr, bio);
>> - bio->bi_end_io = is_read ? f2fs_read_end_io : f2fs_write_end_io;
>> - bio->bi_private = is_read ? NULL : sbi;
>> + if (is_read) {
>> + bio->bi_end_io = f2fs_read_end_io;
>> + bio->bi_private = NULL;
>> + } else {
>> + bio->bi_end_io = f2fs_write_end_io;
>> + bio->bi_private = sbi;
>> + bio->bi_write_hint = io_type_to_rw_hint(sbi, type, temp);
>> + }
>> if (wbc)
>> wbc_init_bio(wbc, bio);
>>
>> @@ -382,7 +389,7 @@ int f2fs_submit_page_bio(struct f2fs_io_info *fio)
>>
>> /* Allocate a new bio */
>> bio = __bio_alloc(fio->sbi, fio->new_blkaddr, fio->io_wbc,
>> - 1, is_read_io(fio->op));
>> + 1, is_read_io(fio->op), fio->type, fio->temp);
>>
>> if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
>> bio_put(bio);
>> @@ -445,7 +452,8 @@ int f2fs_submit_page_write(struct f2fs_io_info *fio)
>> goto out_fail;
>> }
>> io->bio = __bio_alloc(sbi, fio->new_blkaddr, fio->io_wbc,
>> - BIO_MAX_PAGES, false);
>> + BIO_MAX_PAGES, false,
>> + fio->type, fio->temp);
>> io->fio = *fio;
>> }
>>
>> @@ -2287,10 +2295,12 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
>> {
>> struct address_space *mapping = iocb->ki_filp->f_mapping;
>> struct inode *inode = mapping->host;
>> + struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>> size_t count = iov_iter_count(iter);
>> loff_t offset = iocb->ki_pos;
>> int rw = iov_iter_rw(iter);
>> int err;
>> + enum rw_hint hint;
>>
>> err = check_direct_IO(inode, iter, offset);
>> if (err)
>> @@ -2301,11 +2311,18 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
>>
>> trace_f2fs_direct_IO_enter(inode, offset, count, rw);
>>
>> + if (rw == WRITE && sbi->whint_mode == WHINT_MODE_OFF) {
>> + hint = iocb->ki_hint;
>> + iocb->ki_hint = WRITE_LIFE_NOT_SET;
>> + }
>
> In f2fs_preallocate_blocks, we should wrap original iocb->ki_hint with
> WRITE_LIFE_NOT_SET under WHINT_MODE_OFF mode?
>
In f2fs_preallocate_blocks, we should keep the original iocb->ki_hint to
select proper segments. So I think f2fs_direct_IO is the best place
before submiting io.

Thanks,

> Thanks,
>
>> +
>> down_read(&F2FS_I(inode)->dio_rwsem[rw]);
>> err = blockdev_direct_IO(iocb, inode, iter, get_data_block_dio);
>> up_read(&F2FS_I(inode)->dio_rwsem[rw]);
>>
>> if (rw == WRITE) {
>> + if (sbi->whint_mode == WHINT_MODE_OFF)
>> + iocb->ki_hint = hint;
>> if (err > 0) {
>> f2fs_update_iostat(F2FS_I_SB(inode), APP_DIRECT_IO,
>> err);
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index b7ba496..d7c2797 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -1035,6 +1035,11 @@ enum {
>> MAX_TIME,
>> };
>>
>> +enum {
>> + WHINT_MODE_OFF, /* not pass down write hints */
>> + WHINT_MODE_USER, /* try to pass down hints given by users */
>> +};
>> +
>> struct f2fs_sb_info {
>> struct super_block *sb; /* pointer to VFS super block */
>> struct proc_dir_entry *s_proc; /* proc entry */
>> @@ -1218,6 +1223,8 @@ struct f2fs_sb_info {
>> char *s_qf_names[MAXQUOTAS];
>> int s_jquota_fmt; /* Format of quota to use */
>> #endif
>> + /* For which write hints are passed down to block layer */
>> + int whint_mode;
>> };
>>
>> #ifdef CONFIG_F2FS_FAULT_INJECTION
>> @@ -2766,6 +2773,8 @@ int lookup_journal_in_cursum(struct f2fs_journal *journal, int type,
>> int __init create_segment_manager_caches(void);
>> void destroy_segment_manager_caches(void);
>> int rw_hint_to_seg_type(enum rw_hint hint);
>> +enum rw_hint io_type_to_rw_hint(struct f2fs_sb_info *sbi, enum page_type type,
>> + enum temp_type temp);
>>
>> /*
>> * checkpoint.c
>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>> index e5739ce..8bc1fc1 100644
>> --- a/fs/f2fs/segment.c
>> +++ b/fs/f2fs/segment.c
>> @@ -2458,6 +2458,62 @@ int rw_hint_to_seg_type(enum rw_hint hint)
>> }
>> }
>>
>> +/* This returns write hints for each segment type. This hints will be
>> + * passed down to block layer. There are 2 mapping tables which depend on
>> + * the mount option 'whint'.
>> + *
>> + * 1) whint_mode=user-based. F2FS tries to pass down hints given by users.
>> + *
>> + * User F2FS Block
>> + * ---- ---- -----
>> + * META WRITE_LIFE_NOT_SET
>> + * HOT_NODE "
>> + * WARM_NODE "
>> + * COLD_NODE "
>> + * ioctl(COLD) COLD_DATA WRITE_LIFE_EXTREME
>> + * extension list " "
>> + *
>> + * -- buffered io
>> + * WRITE_LIFE_EXTREME COLD_DATA WRITE_LIFE_EXTREME
>> + * WRITE_LIFE_SHORT HOT_DATA WRITE_LIFE_SHORT
>> + * WRITE_LIFE_NOT_SET WARM_DATA WRITE_LIFE_NOT_SET
>> + * WRITE_LIFE_NONE " "
>> + * WRITE_LIFE_MEDIUM " "
>> + * WRITE_LIFE_LONG " "
>> + *
>> + * -- direct io
>> + * WRITE_LIFE_EXTREME COLD_DATA WRITE_LIFE_EXTREME
>> + * WRITE_LIFE_SHORT HOT_DATA WRITE_LIFE_SHORT
>> + * WRITE_LIFE_NOT_SET WARM_DATA WRITE_LIFE_NOT_SET
>> + * WRITE_LIFE_NONE " WRITE_LIFE_NONE
>> + * WRITE_LIFE_MEDIUM " WRITE_LIFE_MEDIUM
>> + * WRITE_LIFE_LONG " WRITE_LIFE_LONG
>> + *
>> + * 2) whint_mode=off. F2FS only passes down WRITE_LIFE_NOT_SET.
>> + *
>> + */
>> +
>> +enum rw_hint io_type_to_rw_hint(struct f2fs_sb_info *sbi,
>> + enum page_type type, enum temp_type temp)
>> +{
>> + if (sbi->whint_mode == WHINT_MODE_USER) {
>> + if (type == DATA) {
>> + switch (temp) {
>> + case COLD:
>> + return WRITE_LIFE_EXTREME;
>> + case HOT:
>> + return WRITE_LIFE_SHORT;
>> + default:
>> + return WRITE_LIFE_NOT_SET;
>> + }
>> + } else {
>> + return WRITE_LIFE_NOT_SET;
>> + }
>> + } else {
>> + return WRITE_LIFE_NOT_SET;
>> + }
>> +}
>> +
>> static int __get_segment_type_2(struct f2fs_io_info *fio)
>> {
>> if (fio->type == DATA)
>> @@ -2645,6 +2701,7 @@ void write_meta_page(struct f2fs_sb_info *sbi, struct page *page,
>> struct f2fs_io_info fio = {
>> .sbi = sbi,
>> .type = META,
>> + .temp = HOT,
>
> Could you check to make sure all .temp being covered?
>
>> .op = REQ_OP_WRITE,
>> .op_flags = REQ_SYNC | REQ_META | REQ_PRIO,
>> .old_blkaddr = page->index,
>> @@ -2693,6 +2750,8 @@ int rewrite_data_page(struct f2fs_io_info *fio)
>> int err;
>>
>> fio->new_blkaddr = fio->old_blkaddr;
>> + /* i/o temperature is needed for passing down write hints */
>> + __get_segment_type(fio);
>> stat_inc_inplace_blocks(fio->sbi);
>>
>> err = f2fs_submit_page_bio(fio);
>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>> index 8173ae6..9e22926 100644
>> --- a/fs/f2fs/super.c
>> +++ b/fs/f2fs/super.c
>> @@ -129,6 +129,7 @@ enum {
>> Opt_jqfmt_vfsold,
>> Opt_jqfmt_vfsv0,
>> Opt_jqfmt_vfsv1,
>> + Opt_whint,
>> Opt_err,
>> };
>>
>> @@ -182,6 +183,7 @@ enum {
>> {Opt_jqfmt_vfsold, "jqfmt=vfsold"},
>> {Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
>> {Opt_jqfmt_vfsv1, "jqfmt=vfsv1"},
>> + {Opt_whint, "whint_mode=%s"},
>> {Opt_err, NULL},
>> };
>>
>> @@ -679,6 +681,22 @@ static int parse_options(struct super_block *sb, char *options)
>> "quota operations not supported");
>> break;
>> #endif
>> + case Opt_whint:
>> + name = match_strdup(&args[0]);
>> + if (!name)
>> + return -ENOMEM;
>> + if (strlen(name) == 10 &&
>> + !strncmp(name, "user-based", 10)) {
>> + sbi->whint_mode = WHINT_MODE_USER;
>> + } else if (strlen(name) == 3 &&
>> + !strncmp(name, "off", 3)) {
>> + sbi->whint_mode = WHINT_MODE_OFF;
>> + } else {
>> + kfree(name);
>> + return -EINVAL;
>> + }
>> + kfree(name);
>> + break;
>> default:
>> f2fs_msg(sb, KERN_ERR,
>> "Unrecognized mount option \"%s\" or missing value",
>> @@ -1225,6 +1243,8 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
>> seq_puts(seq, ",prjquota");
>> #endif
>> f2fs_show_quota_options(seq, sbi->sb);
>> + if (sbi->whint_mode == WHINT_MODE_USER)
>> + seq_printf(seq, ",whint_mode=%s", "user-based");
>>
>> return 0;
>> }
>> @@ -1234,6 +1254,7 @@ static void default_options(struct f2fs_sb_info *sbi)
>> /* init some FS parameters */
>> sbi->active_logs = NR_CURSEG_TYPE;
>> sbi->inline_xattr_size = DEFAULT_INLINE_XATTR_ADDRS;
>> + sbi->whint_mode = WHINT_MODE_OFF;
>>
>> set_opt(sbi, BG_GC);
>> set_opt(sbi, INLINE_XATTR);
>> @@ -1274,6 +1295,7 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
>> bool need_restart_gc = false;
>> bool need_stop_gc = false;
>> bool no_extent_cache = !test_opt(sbi, EXTENT_CACHE);
>> + int old_whint_mode = sbi->whint_mode;
>> #ifdef CONFIG_F2FS_FAULT_INJECTION
>> struct f2fs_fault_info ffi = sbi->fault_info;
>> #endif
>> @@ -1373,7 +1395,7 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
>> need_stop_gc = true;
>> }
>>
>> - if (*flags & SB_RDONLY) {
>> + if (*flags & SB_RDONLY || sbi->whint_mode != old_whint_mode) {
>> writeback_inodes_sb(sb, WB_REASON_SYNC);
>> sync_inodes_sb(sb);
>>
>>
>