On 05/12, Chao Yu wrote: > Hi Jaegeuk, > > On 2017/5/12 2:36, Jaegeuk Kim wrote: > > Hi Chao, > > > > On 05/09, Chao Yu wrote: > >> From: Chao Yu <yuch...@huawei.com> > >> > >> Serialize data/node IOs by using fifo list instead of mutex lock, > >> it will help to enhance concurrency of f2fs, meanwhile keeping LFS > >> IO semantics. > > > > I'm not against to give it a try, but not sure how much we can get a benefit > > from this approach frankly. Have you got a trouble on any lock contention > > from > > the below io_rwsem or mutex? > > Yes, because submitting IOs can be blocked in block layer since there may be: > - limitation of some resources, e.g. request number. > - IO throttle > Holding a global mutex lock in the path is not good idea, as it may cause > potential hungtask or concurrency performance regression. > > So I add this patch to relief impacting of global mutex.
Okay, could you send a modified patch? Then, let me evaluate it. Thanks, > > Thanks, > > > > > Thanks, > > > >> > >> Signed-off-by: Chao Yu <yuch...@huawei.com> > >> --- > >> fs/f2fs/checkpoint.c | 1 + > >> fs/f2fs/data.c | 28 ++++++++++++++++++++++++---- > >> fs/f2fs/f2fs.h | 5 ++++- > >> fs/f2fs/gc.c | 3 ++- > >> fs/f2fs/segment.c | 20 ++++++++++++++------ > >> fs/f2fs/segment.h | 3 ++- > >> 6 files changed, 47 insertions(+), 13 deletions(-) > >> > >> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c > >> index 2a475e83a092..7b3393474f6b 100644 > >> --- a/fs/f2fs/checkpoint.c > >> +++ b/fs/f2fs/checkpoint.c > >> @@ -162,6 +162,7 @@ int ra_meta_pages(struct f2fs_sb_info *sbi, block_t > >> start, int nrpages, > >> .op = REQ_OP_READ, > >> .op_flags = sync ? (REQ_META | REQ_PRIO) : REQ_RAHEAD, > >> .encrypted_page = NULL, > >> + .in_list = false, > >> }; > >> struct blk_plug plug; > >> > >> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > >> index 5f001b471252..89eaa8aaa97b 100644 > >> --- a/fs/f2fs/data.c > >> +++ b/fs/f2fs/data.c > >> @@ -393,10 +393,28 @@ int f2fs_submit_page_mbio(struct f2fs_io_info *fio) > >> struct f2fs_bio_info *io; > >> bool is_read = is_read_io(fio->op); > >> struct page *bio_page; > >> + struct curseg_info *curseg; > >> int err = 0; > >> > >> + if (fio->in_list) > >> + curseg = CURSEG_I(sbi, fio->seg_type); > >> + > >> io = __get_bio_info(sbi, fio->op, fio->type, fio->seg_type); > >> > >> + down_write(&io->io_rwsem); > >> +next: > >> + if (fio->in_list) { > >> + spin_lock(&curseg->io_lock); > >> + if (list_empty(&curseg->io_list)) { > >> + spin_unlock(&curseg->io_lock); > >> + goto out_fail; > >> + } > >> + fio = list_first_entry(&curseg->io_list, > >> + struct f2fs_io_info, list); > >> + list_del(&fio->list); > >> + spin_unlock(&curseg->io_lock); > >> + } > >> + > >> if (fio->old_blkaddr != NEW_ADDR) > >> verify_block_addr(sbi, fio->old_blkaddr); > >> verify_block_addr(sbi, fio->new_blkaddr); > >> @@ -409,8 +427,6 @@ int f2fs_submit_page_mbio(struct f2fs_io_info *fio) > >> if (!is_read) > >> inc_page_count(sbi, WB_DATA_TYPE(bio_page)); > >> > >> - down_write(&io->io_rwsem); > >> - > >> if (io->bio && (io->last_block_in_bio != fio->new_blkaddr - 1 || > >> (io->fio.op != fio->op || io->fio.op_flags != fio->op_flags) || > >> !__same_bdev(sbi, fio->new_blkaddr, io->bio))) > >> @@ -437,9 +453,13 @@ int f2fs_submit_page_mbio(struct f2fs_io_info *fio) > >> > >> io->last_block_in_bio = fio->new_blkaddr; > >> f2fs_trace_ios(fio, 0); > >> + > >> + trace_f2fs_submit_page_mbio(fio->page, fio); > >> + > >> + if (fio->in_list) > >> + goto next; > >> out_fail: > >> up_write(&io->io_rwsem); > >> - trace_f2fs_submit_page_mbio(fio->page, fio); > >> return err; > >> } > >> > >> @@ -752,7 +772,7 @@ static int __allocate_data_block(struct dnode_of_data > >> *dn) > >> set_summary(&sum, dn->nid, dn->ofs_in_node, ni.version); > >> > >> allocate_data_block(sbi, NULL, dn->data_blkaddr, &dn->data_blkaddr, > >> - &sum, CURSEG_WARM_DATA); > >> + &sum, CURSEG_WARM_DATA, NULL, false); > >> set_data_blkaddr(dn); > >> > >> /* update i_size */ > >> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > >> index 9129a6229bc8..6b8e9f051aa2 100644 > >> --- a/fs/f2fs/f2fs.h > >> +++ b/fs/f2fs/f2fs.h > >> @@ -802,8 +802,10 @@ struct f2fs_io_info { > >> block_t old_blkaddr; /* old block address before Cow */ > >> struct page *page; /* page to be written */ > >> struct page *encrypted_page; /* encrypted page */ > >> + struct list_head list; /* serialize IOs */ > >> bool submitted; /* indicate IO submission */ > >> bool need_lock; /* indicate we need to lock cp_rwsem */ > >> + bool in_list; /* indicate fio is in io_list */ > >> }; > >> > >> #define is_read_io(rw) ((rw) == READ) > >> @@ -2274,7 +2276,8 @@ void f2fs_replace_block(struct f2fs_sb_info *sbi, > >> struct dnode_of_data *dn, > >> bool recover_newaddr); > >> void allocate_data_block(struct f2fs_sb_info *sbi, struct page *page, > >> block_t old_blkaddr, block_t *new_blkaddr, > >> - struct f2fs_summary *sum, int type); > >> + struct f2fs_summary *sum, int type, > >> + struct f2fs_io_info *fio, bool add_list); > >> void f2fs_wait_on_page_writeback(struct page *page, > >> enum page_type type, bool ordered); > >> void f2fs_wait_on_encrypted_page_writeback(struct f2fs_sb_info *sbi, > >> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c > >> index 8b267ca30926..ac2f74e40eea 100644 > >> --- a/fs/f2fs/gc.c > >> +++ b/fs/f2fs/gc.c > >> @@ -590,6 +590,7 @@ static void move_encrypted_block(struct inode *inode, > >> block_t bidx, > >> .op = REQ_OP_READ, > >> .op_flags = 0, > >> .encrypted_page = NULL, > >> + .in_list = false, > >> }; > >> struct dnode_of_data dn; > >> struct f2fs_summary sum; > >> @@ -633,7 +634,7 @@ static void move_encrypted_block(struct inode *inode, > >> block_t bidx, > >> fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr; > >> > >> allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr, > >> - &sum, fio.seg_type); > >> + &sum, fio.seg_type, NULL, false); > >> > >> fio.encrypted_page = pagecache_get_page(META_MAPPING(fio.sbi), newaddr, > >> FGP_LOCK | FGP_CREAT, GFP_NOFS); > >> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > >> index c047b5d8b9d3..d4975b8f4620 100644 > >> --- a/fs/f2fs/segment.c > >> +++ b/fs/f2fs/segment.c > >> @@ -2100,7 +2100,8 @@ static int __get_segment_type(struct page *page, > >> enum page_type p_type) > >> > >> void allocate_data_block(struct f2fs_sb_info *sbi, struct page *page, > >> block_t old_blkaddr, block_t *new_blkaddr, > >> - struct f2fs_summary *sum, int type) > >> + struct f2fs_summary *sum, int type, > >> + struct f2fs_io_info *fio, bool add_list) > >> { > >> struct sit_info *sit_i = SIT_I(sbi); > >> struct curseg_info *curseg = CURSEG_I(sbi, type); > >> @@ -2136,6 +2137,14 @@ void allocate_data_block(struct f2fs_sb_info *sbi, > >> struct page *page, > >> if (page && IS_NODESEG(type)) > >> fill_node_footer_blkaddr(page, NEXT_FREE_BLKADDR(sbi, curseg)); > >> > >> + if (add_list) { > >> + INIT_LIST_HEAD(&fio->list); > >> + fio->in_list = true; > >> + spin_lock(&curseg->io_lock); > >> + list_add_tail(&fio->list, &curseg->io_list); > >> + spin_unlock(&curseg->io_lock); > >> + } > >> + > >> mutex_unlock(&curseg->curseg_mutex); > >> } > >> > >> @@ -2145,10 +2154,9 @@ static void do_write_page(struct f2fs_summary *sum, > >> struct f2fs_io_info *fio) > >> > >> fio->seg_type = __get_segment_type(fio->page, fio->type); > >> > >> - mutex_lock(&CURSEG_I(fio->sbi, fio->seg_type)->wio_mutex); > >> reallocate: > >> allocate_data_block(fio->sbi, fio->page, fio->old_blkaddr, > >> - &fio->new_blkaddr, sum, fio->seg_type); > >> + &fio->new_blkaddr, sum, fio->seg_type, fio, true); > >> > >> /* writeout dirty page into bdev */ > >> err = f2fs_submit_page_mbio(fio); > >> @@ -2156,8 +2164,6 @@ static void do_write_page(struct f2fs_summary *sum, > >> struct f2fs_io_info *fio) > >> fio->old_blkaddr = fio->new_blkaddr; > >> goto reallocate; > >> } > >> - > >> - mutex_unlock(&CURSEG_I(fio->sbi, fio->seg_type)->wio_mutex); > >> } > >> > >> void write_meta_page(struct f2fs_sb_info *sbi, struct page *page) > >> @@ -2171,6 +2177,7 @@ void write_meta_page(struct f2fs_sb_info *sbi, > >> struct page *page) > >> .new_blkaddr = page->index, > >> .page = page, > >> .encrypted_page = NULL, > >> + .in_list = false, > >> }; > >> > >> if (unlikely(page->index >= MAIN_BLKADDR(sbi))) > >> @@ -2978,7 +2985,8 @@ static int build_curseg(struct f2fs_sb_info *sbi) > >> array[i].bio_info.sbi = sbi; > >> array[i].bio_info.bio = NULL; > >> > >> - mutex_init(&array[i].wio_mutex); > >> + spin_lock_init(&array[i].io_lock); > >> + INIT_LIST_HEAD(&array[i].io_list); > >> } > >> return restore_curseg_summaries(sbi); > >> } > >> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h > >> index 701944b462cd..b6f5dffeaa61 100644 > >> --- a/fs/f2fs/segment.h > >> +++ b/fs/f2fs/segment.h > >> @@ -283,7 +283,8 @@ struct curseg_info { > >> struct rw_semaphore journal_rwsem; /* protect journal area */ > >> struct f2fs_journal *journal; /* cached journal info */ > >> struct f2fs_bio_info bio_info; /* for log bios */ > >> - struct mutex wio_mutex; /* serialize DATA/NODE IOs */ > >> + spinlock_t io_lock; /* serialize DATA/NODE IOs */ > >> + struct list_head io_list; /* tracking fios */ > >> unsigned char alloc_type; /* current allocation type */ > >> unsigned int segno; /* current segment number */ > >> unsigned short next_blkoff; /* next block offset to write */ > >> -- > >> 2.12.2.575.gb14f27f > > > > . > >