Re: [PATCH] f2fs: split bio cache

From: Jaegeuk Kim
Date: Wed May 10 2017 - 22:35:17 EST


On 05/11, Chao Yu wrote:
> On 2017/5/11 7:50, Jaegeuk Kim wrote:
> > On 05/09, Chao Yu wrote:
> >> Hi Jaegeuk,
> >>
> >> On 2017/5/9 5:23, Jaegeuk Kim wrote:
> >>> Hi Chao,
> >>>
> >>> I can't see a strong reason to split meta from data/node and rename the existing
> >>> function names. Instead, how about keeping the existing one while adding some
> >>> page types to deal with log types?
> >>
> >> Hmm.. before write this patch, I have thought about this implementation which
> >> adds HOT_DATA/WARM_DATA/.. into page_type enum, but the final target is making
> >> different temperature log-header being with independent bio cache, io lock, and
> >> io list, eliminating interaction of different temperature IOs, also expanding
> >> f2fs' scalability when adding more log-headers. If we don't split meta from
> >> data/node, it's a little bit hard to approach this. What do you think?
> >
> > I submitted clean-up patches. How about this on top of them?
>
> After splitting, bio caches is connected to log-header, so why not moving bio
> cache into log-header (SM_I(sbi)->curseg_array)? after the merging:
> - we could avoid redundant enum. e.g. temp_type, page_type::{DATA/NODE}, since
> we have seg_type enum instead.
> - once we add special log-header like journal log or random IO log making
> DATA/NODE and HOT/WARM/COLD non-orthogonalization, we just need to change few
> codes to adjust it.

Well, I perfer to keep block allocation and IO control in a separate way as is.
Moreover, I don't think performance gain would be large enough comparing to what
we need to change both of whole flows.

Thanks,

>
> How do you think?
>
> Thanks,
>
> >
> > ---
> > fs/f2fs/data.c | 51 +++++++++++++++++++++++++++++++++------------
> > fs/f2fs/f2fs.h | 10 ++++++++-
> > fs/f2fs/gc.c | 2 ++
> > fs/f2fs/segment.c | 24 +++++++++++++++------
> > fs/f2fs/segment.h | 4 ++++
> > fs/f2fs/super.c | 21 ++++++++++++++++---
> > include/trace/events/f2fs.h | 14 ++++++++++++-
> > 7 files changed, 102 insertions(+), 24 deletions(-)
> >
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index 06bb2042385e..49b7e3918484 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -282,21 +282,30 @@ static bool has_merged_page(struct f2fs_sb_info *sbi, struct inode *inode,
> > nid_t ino, pgoff_t idx, enum page_type type)
> > {
> > enum page_type btype = PAGE_TYPE_OF_BIO(type);
> > - struct f2fs_bio_info *io = &sbi->write_io[btype];
> > - bool ret;
> > + enum temp_type temp;
> > + struct f2fs_bio_info *io;
> > + bool ret = false;
> >
> > - down_read(&io->io_rwsem);
> > - ret = __has_merged_page(io, inode, ino, idx);
> > - up_read(&io->io_rwsem);
> > + for (temp = HOT; temp < NR_TEMP_TYPE; temp++) {
> > + io = sbi->write_io[btype] + temp;
> > +
> > + down_read(&io->io_rwsem);
> > + ret = __has_merged_page(io, inode, ino, idx);
> > + up_read(&io->io_rwsem);
> > +
> > + /* TODO: use HOT temp only for meta pages now. */
> > + if (ret || btype == META)
> > + break;
> > + }
> > return ret;
> > }
> >
> > static void __f2fs_submit_merged_write(struct f2fs_sb_info *sbi,
> > struct inode *inode, nid_t ino, pgoff_t idx,
> > - enum page_type type)
> > + enum page_type type, enum temp_type temp)
> > {
> > enum page_type btype = PAGE_TYPE_OF_BIO(type);
> > - struct f2fs_bio_info *io = &sbi->write_io[btype];
> > + struct f2fs_bio_info *io = sbi->write_io[btype] + temp;
> >
> > down_write(&io->io_rwsem);
> >
> > @@ -316,17 +325,34 @@ static void __f2fs_submit_merged_write(struct f2fs_sb_info *sbi,
> > up_write(&io->io_rwsem);
> > }
> >
> > +static void __submit_merged_write_cond(struct f2fs_sb_info *sbi,
> > + struct inode *inode, nid_t ino, pgoff_t idx,
> > + enum page_type type, bool force)
> > +{
> > + enum temp_type temp;
> > +
> > + if (!force && !has_merged_page(sbi, inode, ino, idx, type))
> > + return;
> > +
> > + for (temp = HOT; temp < NR_TEMP_TYPE; temp++) {
> > + __f2fs_submit_merged_write(sbi, inode, ino, idx, type, temp);
> > +
> > + /* TODO: use HOT temp only for meta pages now. */
> > + if (type >= META)
> > + break;
> > + }
> > +}
> > +
> > void f2fs_submit_merged_write(struct f2fs_sb_info *sbi, enum page_type type)
> > {
> > - __f2fs_submit_merged_write(sbi, NULL, 0, 0, type);
> > + __submit_merged_write_cond(sbi, NULL, 0, 0, type, true);
> > }
> >
> > void f2fs_submit_merged_write_cond(struct f2fs_sb_info *sbi,
> > struct inode *inode, nid_t ino, pgoff_t idx,
> > enum page_type type)
> > {
> > - if (has_merged_page(sbi, inode, ino, idx, type))
> > - __f2fs_submit_merged_write(sbi, inode, ino, idx, type);
> > + __submit_merged_write_cond(sbi, inode, ino, idx, type, false);
> > }
> >
> > void f2fs_flush_merged_writes(struct f2fs_sb_info *sbi)
> > @@ -369,7 +395,7 @@ int f2fs_submit_page_write(struct f2fs_io_info *fio)
> > {
> > struct f2fs_sb_info *sbi = fio->sbi;
> > enum page_type btype = PAGE_TYPE_OF_BIO(fio->type);
> > - struct f2fs_bio_info *io = &sbi->write_io[btype];
> > + struct f2fs_bio_info *io = sbi->write_io[btype] + fio->temp;
> > struct page *bio_page;
> > int err = 0;
> >
> > @@ -405,8 +431,7 @@ int f2fs_submit_page_write(struct f2fs_io_info *fio)
> > io->fio = *fio;
> > }
> >
> > - if (bio_add_page(io->bio, bio_page, PAGE_SIZE, 0) <
> > - PAGE_SIZE) {
> > + if (bio_add_page(io->bio, bio_page, PAGE_SIZE, 0) < PAGE_SIZE) {
> > __submit_merged_bio(io);
> > goto alloc_new;
> > }
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index bf837458cb18..90e97bc11972 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -792,9 +792,17 @@ enum page_type {
> > OPU,
> > };
> >
> > +enum temp_type {
> > + HOT = 0, /* must be zero for meta bio */
> > + WARM,
> > + COLD,
> > + NR_TEMP_TYPE,
> > +};
> > +
> > struct f2fs_io_info {
> > struct f2fs_sb_info *sbi; /* f2fs_sb_info pointer */
> > enum page_type type; /* contains DATA/NODE/META/META_FLUSH */
> > + enum temp_type temp; /* contains HOT/WARM/COLD */
> > int op; /* contains REQ_OP_ */
> > int op_flags; /* req_flag_bits */
> > block_t new_blkaddr; /* new block address to be written */
> > @@ -880,7 +888,7 @@ struct f2fs_sb_info {
> >
> > /* for bio operations */
> > struct f2fs_bio_info read_io; /* for read bios */
> > - struct f2fs_bio_info write_io[NR_PAGE_TYPE]; /* for write bios */
> > + struct f2fs_bio_info *write_io[NR_PAGE_TYPE]; /* for write bios */
> > struct mutex wio_mutex[NODE + 1]; /* bio ordering for NODE/DATA */
> > int write_io_size_bits; /* Write IO size bits */
> > mempool_t *write_io_dummy; /* Dummy pages */
> > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> > index 67b87155bc48..e2b13558a915 100644
> > --- a/fs/f2fs/gc.c
> > +++ b/fs/f2fs/gc.c
> > @@ -586,6 +586,7 @@ static void move_encrypted_block(struct inode *inode, block_t bidx,
> > struct f2fs_io_info fio = {
> > .sbi = F2FS_I_SB(inode),
> > .type = DATA,
> > + .temp = COLD,
> > .op = REQ_OP_READ,
> > .op_flags = 0,
> > .encrypted_page = NULL,
> > @@ -712,6 +713,7 @@ static void move_data_page(struct inode *inode, block_t bidx, int gc_type,
> > struct f2fs_io_info fio = {
> > .sbi = F2FS_I_SB(inode),
> > .type = DATA,
> > + .temp = COLD,
> > .op = REQ_OP_WRITE,
> > .op_flags = REQ_SYNC,
> > .old_blkaddr = NULL_ADDR,
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index c9f3a2faee21..da4fd2c29e86 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -2084,17 +2084,29 @@ static int __get_segment_type_6(struct f2fs_io_info *fio)
> >
> > static int __get_segment_type(struct f2fs_io_info *fio)
> > {
> > + int type;
> > +
> > switch (fio->sbi->active_logs) {
> > case 2:
> > - return __get_segment_type_2(fio);
> > + type = __get_segment_type_2(fio);
> > + break;
> > case 4:
> > - return __get_segment_type_4(fio);
> > + type = __get_segment_type_4(fio);
> > + break;
> > + case 6:
> > + type = __get_segment_type_6(fio);
> > + break;
> > + default:
> > + f2fs_bug_on(fio->sbi, true);
> > }
> >
> > - /* NR_CURSEG_TYPE(6) logs by default */
> > - f2fs_bug_on(fio->sbi, fio->sbi->active_logs != NR_CURSEG_TYPE);
> > -
> > - return __get_segment_type_6(fio);
> > + if (IS_HOT(type))
> > + fio->temp = HOT;
> > + else if (IS_WARM(type))
> > + fio->temp = WARM;
> > + else
> > + fio->temp = COLD;
> > + return type;
> > }
> >
> > void allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
> > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
> > index 10bf05d4cff4..e9ba1f1d9723 100644
> > --- a/fs/f2fs/segment.h
> > +++ b/fs/f2fs/segment.h
> > @@ -27,6 +27,10 @@
> > #define IS_DATASEG(t) ((t) <= CURSEG_COLD_DATA)
> > #define IS_NODESEG(t) ((t) >= CURSEG_HOT_NODE)
> >
> > +#define IS_HOT(t) ((t) == CURSEG_HOT_NODE || (t) == CURSEG_HOT_DATA)
> > +#define IS_WARM(t) ((t) == CURSEG_WARM_NODE || (t) == CURSEG_WARM_DATA)
> > +#define IS_COLD(t) ((t) == CURSEG_COLD_NODE || (t) == CURSEG_COLD_DATA)
> > +
> > #define IS_CURSEG(sbi, seg) \
> > (((seg) == CURSEG_I(sbi, CURSEG_HOT_DATA)->segno) || \
> > ((seg) == CURSEG_I(sbi, CURSEG_WARM_DATA)->segno) || \
> > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > index 104a571a41c0..91599c9c3ef6 100644
> > --- a/fs/f2fs/super.c
> > +++ b/fs/f2fs/super.c
> > @@ -768,6 +768,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi)
> > static void f2fs_put_super(struct super_block *sb)
> > {
> > struct f2fs_sb_info *sbi = F2FS_SB(sb);
> > + int i;
> >
> > if (sbi->s_proc) {
> > remove_proc_entry("segment_info", sbi->s_proc);
> > @@ -838,6 +839,8 @@ static void f2fs_put_super(struct super_block *sb)
> > destroy_device_list(sbi);
> > mempool_destroy(sbi->write_io_dummy);
> > destroy_percpu_info(sbi);
> > + for (i = 0; i < NR_PAGE_TYPE; i++)
> > + kfree(sbi->write_io[i]);
> > kfree(sbi);
> > }
> >
> > @@ -1954,9 +1957,19 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> > sbi->read_io.sbi = sbi;
> > sbi->read_io.bio = NULL;
> > for (i = 0; i < NR_PAGE_TYPE; i++) {
> > - init_rwsem(&sbi->write_io[i].io_rwsem);
> > - sbi->write_io[i].sbi = sbi;
> > - sbi->write_io[i].bio = NULL;
> > + int n = (i == META) ? 1: NR_TEMP_TYPE;
> > + int j;
> > +
> > + sbi->write_io[i] = kmalloc(n * sizeof(struct f2fs_bio_info),
> > + GFP_KERNEL);
> > + if (!sbi->write_io[i])
> > + goto free_options;
> > +
> > + for (j = HOT; j < n; j++) {
> > + init_rwsem(&sbi->write_io[i][j].io_rwsem);
> > + sbi->write_io[i][j].sbi = sbi;
> > + sbi->write_io[i][j].bio = NULL;
> > + }
> > }
> >
> > init_rwsem(&sbi->cp_rwsem);
> > @@ -2202,6 +2215,8 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> > free_io_dummy:
> > mempool_destroy(sbi->write_io_dummy);
> > free_options:
> > + for (i = 0; i < NR_PAGE_TYPE; i++)
> > + kfree(sbi->write_io[i]);
> > destroy_percpu_info(sbi);
> > kfree(options);
> > free_sb_buf:
> > diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
> > index 5805d92893a8..6f77a2755abb 100644
> > --- a/include/trace/events/f2fs.h
> > +++ b/include/trace/events/f2fs.h
> > @@ -19,6 +19,9 @@ TRACE_DEFINE_ENUM(INMEM_INVALIDATE);
> > TRACE_DEFINE_ENUM(INMEM_REVOKE);
> > TRACE_DEFINE_ENUM(IPU);
> > TRACE_DEFINE_ENUM(OPU);
> > +TRACE_DEFINE_ENUM(HOT);
> > +TRACE_DEFINE_ENUM(WARM);
> > +TRACE_DEFINE_ENUM(COLD);
> > TRACE_DEFINE_ENUM(CURSEG_HOT_DATA);
> > TRACE_DEFINE_ENUM(CURSEG_WARM_DATA);
> > TRACE_DEFINE_ENUM(CURSEG_COLD_DATA);
> > @@ -59,6 +62,12 @@ TRACE_DEFINE_ENUM(CP_TRIMMED);
> > { IPU, "IN-PLACE" }, \
> > { OPU, "OUT-OF-PLACE" })
> >
> > +#define show_block_temp(temp) \
> > + __print_symbolic(temp, \
> > + { HOT, "HOT" }, \
> > + { WARM, "WARM" }, \
> > + { COLD, "COLD" })
> > +
> > #define F2FS_OP_FLAGS (REQ_RAHEAD | REQ_SYNC | REQ_META | REQ_PRIO | \
> > REQ_PREFLUSH | REQ_FUA)
> > #define F2FS_BIO_FLAG_MASK(t) (t & F2FS_OP_FLAGS)
> > @@ -757,6 +766,7 @@ DECLARE_EVENT_CLASS(f2fs__submit_page_bio,
> > __field(block_t, new_blkaddr)
> > __field(int, op)
> > __field(int, op_flags)
> > + __field(int, temp)
> > __field(int, type)
> > ),
> >
> > @@ -768,16 +778,18 @@ DECLARE_EVENT_CLASS(f2fs__submit_page_bio,
> > __entry->new_blkaddr = fio->new_blkaddr;
> > __entry->op = fio->op;
> > __entry->op_flags = fio->op_flags;
> > + __entry->temp = fio->temp;
> > __entry->type = fio->type;
> > ),
> >
> > TP_printk("dev = (%d,%d), ino = %lu, page_index = 0x%lx, "
> > - "oldaddr = 0x%llx, newaddr = 0x%llx, rw = %s(%s), type = %s",
> > + "oldaddr = 0x%llx, newaddr = 0x%llx, rw = %s(%s), type = %s_%s",
> > show_dev_ino(__entry),
> > (unsigned long)__entry->index,
> > (unsigned long long)__entry->old_blkaddr,
> > (unsigned long long)__entry->new_blkaddr,
> > show_bio_type(__entry->op, __entry->op_flags),
> > + show_block_temp(__entry->temp),
> > show_block_type(__entry->type))
> > );
> >
> >