Hi Chao, On Mon, Jan 25, 2016 at 05:42:40PM +0800, Chao Yu wrote: > Hi Jaegeuk, > > > -----Original Message----- > > From: Jaegeuk Kim [mailto:jaegeuk@xxxxxxxxxx] > > Sent: Sunday, January 24, 2016 4:16 AM > > To: linux-kernel@xxxxxxxxxxxxxxx; linux-fsdevel@xxxxxxxxxxxxxxx; > > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > > Cc: Jaegeuk Kim > > Subject: [f2fs-dev] [PATCH 1/2] f2fs: avoid multiple node page writes due to inline_data > > > > The sceanrio is: > > 1. create fully node blocks > > 2. flush node blocks > > 3. write inline_data for all the node blocks again > > 4. flush node blocks redundantly > > > > Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> > > --- > > fs/f2fs/data.c | 14 +++++++++++--- > > 1 file changed, 11 insertions(+), 3 deletions(-) > > > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > > index 8d0d9ec..011456e 100644 > > --- a/fs/f2fs/data.c > > +++ b/fs/f2fs/data.c > > @@ -1622,14 +1622,22 @@ static int f2fs_write_end(struct file *file, > > > > trace_f2fs_write_end(inode, pos, len, copied); > > > > - set_page_dirty(page); > > - > > if (pos + copied > i_size_read(inode)) { > > i_size_write(inode, pos + copied); > > mark_inode_dirty(inode); > > - update_inode_page(inode); > > } > > > > + if (f2fs_has_inline_data(inode) && > > + is_inode_flag_set(F2FS_I(inode), FI_DATA_EXIST)) { > > + int err = f2fs_write_inline_data(inode, page); > > Oh, I'm sure this can fix that issue, but IMO: > a) this implementation has side-effect, it triggers inline data copying > between data page and node page whenever user write inline datas, so if > user updates inline data frequently, write-through approach would cause > memory copy overhead. Agreed. > b) inline storm should be a rare case, as we didn't get any report about > problem for long time until Dave's, and write_end is a hot path, I think > it's better to be cautious to change our inline data cache policy for > fixing a rare issue in hot path. > > What about delaying the merge operation? like: > 1) as I proposed before, merging inline page into inode page when > detecting free_sections <= (node_secs + 2 * dent_secs + inline_secs). > 2) merge inline page into inode page before writeback inode page in > sync_node_pages. Okay, I'm thinking more general way where we can get rid of every inlien_data write when we flush node pages. I've been testing this patch. >From ebddf607c64da691fef08cf68a8ecadafd5d896b Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> Date: Mon, 25 Jan 2016 05:57:05 -0800 Subject: [PATCH] f2fs: avoid multiple node page writes due to inline_data The sceanrio is: 1. create fully node blocks 2. flush node blocks 3. write inline_data for all the node blocks again 4. flush node blocks redundantly So, this patch tries to flush inline_data when flushing node blocks. Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> --- fs/f2fs/data.c | 1 + fs/f2fs/inline.c | 2 ++ fs/f2fs/node.c | 35 +++++++++++++++++++++++++++++++++++ fs/f2fs/node.h | 15 +++++++++++++++ 4 files changed, 53 insertions(+) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 6925c10..9043ecf 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -1464,6 +1464,7 @@ restart: if (pos + len <= MAX_INLINE_DATA) { read_inline_data(page, ipage); set_inode_flag(F2FS_I(inode), FI_DATA_EXIST); + set_inline_node(ipage); sync_inode_page(&dn); } else { err = f2fs_convert_inline_page(&dn, page); diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c index 8df13e5..fc4d298 100644 --- a/fs/f2fs/inline.c +++ b/fs/f2fs/inline.c @@ -159,6 +159,7 @@ no_update: /* clear inline data and flag after data writeback */ truncate_inline_inode(dn->inode_page, 0); + clear_inline_node(dn->inode_page); clear_out: stat_dec_inline_inode(dn->inode); f2fs_clear_inline_inode(dn->inode); @@ -233,6 +234,7 @@ int f2fs_write_inline_data(struct inode *inode, struct page *page) set_inode_flag(F2FS_I(inode), FI_DATA_EXIST); sync_inode_page(&dn); + clear_inline_node(dn.inode_page); f2fs_put_dnode(&dn); return 0; } diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index 23b800d..1c5023e 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -1154,6 +1154,33 @@ void sync_inode_page(struct dnode_of_data *dn) dn->node_changed = ret ? true: false; } +static void flush_inline_data(struct f2fs_sb_info *sbi, nid_t ino) +{ + struct inode *inode; + struct page *page; + + inode = ilookup(sbi->sb, ino); + if (!inode) + return; + + page = find_lock_page(inode->i_mapping, 0); + if (!page) + goto iput_out; + + if (!PageDirty(page)) + goto put_page_out; + + if (!clear_page_dirty_for_io(page)) + goto put_page_out; + + if (!f2fs_write_inline_data(inode, page)) + inode_dec_dirty_pages(inode); +put_page_out: + f2fs_put_page(page, 1); +iput_out: + iput(inode); +} + int sync_node_pages(struct f2fs_sb_info *sbi, nid_t ino, struct writeback_control *wbc) { @@ -1221,6 +1248,14 @@ continue_unlock: goto continue_unlock; } + /* flush inline_data */ + if (!ino && is_inline_node(page)) { + clear_inline_node(page); + unlock_page(page); + flush_inline_data(sbi, ino_of_node(page)); + continue; + } + if (!clear_page_dirty_for_io(page)) goto continue_unlock; diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h index 23bd992..1f4f9d4 100644 --- a/fs/f2fs/node.h +++ b/fs/f2fs/node.h @@ -379,6 +379,21 @@ static inline int is_node(struct page *page, int type) #define is_fsync_dnode(page) is_node(page, FSYNC_BIT_SHIFT) #define is_dent_dnode(page) is_node(page, DENT_BIT_SHIFT) +static inline int is_inline_node(struct page *page) +{ + return PageChecked(page); +} + +static inline void set_inline_node(struct page *page) +{ + SetPageChecked(page); +} + +static inline void clear_inline_node(struct page *page) +{ + ClearPageChecked(page); +} + static inline void set_cold_node(struct inode *inode, struct page *page) { struct f2fs_node *rn = F2FS_NODE(page); -- 2.6.3 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
