Re: [f2fs-dev] [PATCH 1/2] f2fs: avoid multiple node page writes due to inline_data

2016-01-26 Thread Jaegeuk Kim 
Hi Chao,

On Tue, Jan 26, 2016 at 02:58:53PM +0800, Chao Yu wrote:
> Hi Jaegeuk,
> 
> > -Original Message-
> > From: Jaegeuk Kim [mailto:jaeg...@kernel.org]
> > Sent: Tuesday, January 26, 2016 3:18 AM
> > To: Chao Yu
> > Cc: linux-kernel@vger.kernel.org; linux-fsde...@vger.kernel.org;
> > linux-f2fs-de...@lists.sourceforge.net
> > Subject: Re: [f2fs-dev] [PATCH 1/2] f2fs: avoid multiple node page writes 
> > due to inline_data
> > 
> > Hi Chao,
> > 
> > On Mon, Jan 25, 2016 at 05:42:40PM +0800, Chao Yu wrote:
> > > Hi Jaegeuk,
> > >
> > > > -Original Message-
> > > > From: Jaegeuk Kim [mailto:jaeg...@kernel.org]
> > > > Sent: Sunday, January 24, 2016 4:16 AM
> > > > To: linux-kernel@vger.kernel.org; linux-fsde...@vger.kernel.org;
> > > > linux-f2fs-de...@lists.sourceforge.net
> > > > 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 
> > > > ---
> > > >  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 encountered deadlock issue, could you have a look at it?

Yeah, I've been stablizing this for a while.
Please check f2fs.git/dev-test.

Thanks,

> 
> ==
>  [ INFO: possible circular locking dependency detected ]
>  4.5.0-rc1 #45 Tainted: G   O
>  ---
>  fstrim/15301 is trying to acquire lock:
>   (sb_internal#2){..}, at: [] __sb_start_write+0xda/0xf0
> 
>  but task is already holding lock:
>   (>cp_rwsem){..}, at: [] 
> block_operations+0x82/0x130 [f2fs]
> 
>  which lock already depends on the new lock.
> 
> 
>  the existing dependency chain (in reverse order) is:
> 
>  -> #1 (>cp_rwsem){..}:
> [] lock_acquire+0xb7/0x130
> [] down_read+0x39/0x50
> [] f2fs_evict_inode+0x26f/0x370 [f2fs]
> [] evict+0xdd/0x1d0
> [] iput+0x19f/0x250
> [] do_unlinkat+0x20d/0x310
> [] Sy

Re: [f2fs-dev] [PATCH 1/2] f2fs: avoid multiple node page writes due to inline_data

2016-01-26 Thread Jaegeuk Kim 
Hi Chao,

On Tue, Jan 26, 2016 at 02:58:53PM +0800, Chao Yu wrote:
> Hi Jaegeuk,
> 
> > -Original Message-
> > From: Jaegeuk Kim [mailto:jaeg...@kernel.org]
> > Sent: Tuesday, January 26, 2016 3:18 AM
> > To: Chao Yu
> > Cc: linux-kernel@vger.kernel.org; linux-fsde...@vger.kernel.org;
> > linux-f2fs-de...@lists.sourceforge.net
> > Subject: Re: [f2fs-dev] [PATCH 1/2] f2fs: avoid multiple node page writes 
> > due to inline_data
> > 
> > Hi Chao,
> > 
> > On Mon, Jan 25, 2016 at 05:42:40PM +0800, Chao Yu wrote:
> > > Hi Jaegeuk,
> > >
> > > > -Original Message-
> > > > From: Jaegeuk Kim [mailto:jaeg...@kernel.org]
> > > > Sent: Sunday, January 24, 2016 4:16 AM
> > > > To: linux-kernel@vger.kernel.org; linux-fsde...@vger.kernel.org;
> > > > linux-f2fs-de...@lists.sourceforge.net
> > > > 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 <jaeg...@kernel.org>
> > > > ---
> > > >  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 encountered deadlock issue, could you have a look at it?

Yeah, I've been stablizing this for a while.
Please check f2fs.git/dev-test.

Thanks,

> 
> ==
>  [ INFO: possible circular locking dependency detected ]
>  4.5.0-rc1 #45 Tainted: G   O
>  ---
>  fstrim/15301 is trying to acquire lock:
>   (sb_internal#2){..}, at: [] __sb_start_write+0xda/0xf0
> 
>  but task is already holding lock:
>   (>cp_rwsem){..}, at: [] 
> block_operations+0x82/0x130 [f2fs]
> 
>  which lock already depends on the new lock.
> 
> 
>  the existing dependency chain (in reverse order) is:
> 
>  -> #1 (>cp_rwsem){..}:
> [] lock_acquire+0xb7/0x130
> [] down_read+0x39/0x50
> [] f2fs_evict_inode+0x26f/0x370 [f2fs]
> [] evict+0xdd/0x1d0
> [] iput+0x19f/0x250
> [] do_unlinkat+0x20d

RE: [f2fs-dev] [PATCH 1/2] f2fs: avoid multiple node page writes due to inline_data

2016-01-25 Thread Chao Yu 
Hi Jaegeuk,

> -Original Message-
> From: Jaegeuk Kim [mailto:jaeg...@kernel.org]
> Sent: Tuesday, January 26, 2016 3:18 AM
> To: Chao Yu
> Cc: linux-kernel@vger.kernel.org; linux-fsde...@vger.kernel.org;
> linux-f2fs-de...@lists.sourceforge.net
> Subject: Re: [f2fs-dev] [PATCH 1/2] f2fs: avoid multiple node page writes due 
> to inline_data
> 
> Hi Chao,
> 
> On Mon, Jan 25, 2016 at 05:42:40PM +0800, Chao Yu wrote:
> > Hi Jaegeuk,
> >
> > > -Original Message-
> > > From: Jaegeuk Kim [mailto:jaeg...@kernel.org]
> > > Sent: Sunday, January 24, 2016 4:16 AM
> > > To: linux-kernel@vger.kernel.org; linux-fsde...@vger.kernel.org;
> > > linux-f2fs-de...@lists.sourceforge.net
> > > 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 
> > > ---
> > >  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 encountered deadlock issue, could you have a look at it?

==
 [ INFO: possible circular locking dependency detected ]
 4.5.0-rc1 #45 Tainted: G   O
 ---
 fstrim/15301 is trying to acquire lock:
  (sb_internal#2){..}, at: [] __sb_start_write+0xda/0xf0

 but task is already holding lock:
  (>cp_rwsem){..}, at: [] 
block_operations+0x82/0x130 [f2fs]

 which lock already depends on the new lock.


 the existing dependency chain (in reverse order) is:

 -> #1 (>cp_rwsem){..}:
[] lock_acquire+0xb7/0x130
[] down_read+0x39/0x50
[] f2fs_evict_inode+0x26f/0x370 [f2fs]
[] evict+0xdd/0x1d0
[] iput+0x19f/0x250
[] do_unlinkat+0x20d/0x310
[] SyS_unlinkat+0x22/0x40
[] entry_SYSCALL_64_fastpath+0x12/0x6f

 -> #0 (sb_internal#2){..}:
[] __lock_acquire+0x132b/0x1770
[] lock_acquire+0xb7/0x130
[] percpu_down_read+0x3c/0x80
[] __sb_start_write+0xda/0xf0
[] f2fs_evict_inode+0x221/0x370 [f2fs]
[] evict+0xdd/0x1d0
[] iput+0x19f/0x250
[] sync_node_pages+0x703/0x900 [f2fs]
[] block_operations+0x10a/0x130 [f2fs]
[] write_checkpoint+0xc4/0xb80 [f2fs]
[] f2fs_trim_fs+0x122/0x1d0 [f2fs]
[] f2fs_ioctl+0x7fa/0x9d0 [f2fs]
[] vfs_ioctl+0x18/0x40
[] do_vfs_ioctl+0x96/0x680
[] SyS_ioctl+0x92/0xa0
[] entry_SYSCALL_64_fastpath+0x12/0x6f

 other info that might help us debug this:

  Possible un

Re: [f2fs-dev] [PATCH 1/2] f2fs: avoid multiple node page writes due to inline_data

2016-01-25 Thread Jaegeuk Kim 
Hi Chao,

On Mon, Jan 25, 2016 at 05:42:40PM +0800, Chao Yu wrote:
> Hi Jaegeuk,
> 
> > -Original Message-
> > From: Jaegeuk Kim [mailto:jaeg...@kernel.org]
> > Sent: Sunday, January 24, 2016 4:16 AM
> > To: linux-kernel@vger.kernel.org; linux-fsde...@vger.kernel.org;
> > linux-f2fs-de...@lists.sourceforge.net
> > 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 
> > ---
> >  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 
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 
---
 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();
} else {
err = f2fs_convert_inline_page(, 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();
+   clear_inline_node(dn.inode_page);
f2fs_put_dnode();
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,

RE: [f2fs-dev] [PATCH 1/2] f2fs: avoid multiple node page writes due to inline_data

2016-01-25 Thread Chao Yu 
Hi Jaegeuk,

> -Original Message-
> From: Jaegeuk Kim [mailto:jaeg...@kernel.org]
> Sent: Sunday, January 24, 2016 4:16 AM
> To: linux-kernel@vger.kernel.org; linux-fsde...@vger.kernel.org;
> linux-f2fs-de...@lists.sourceforge.net
> 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 
> ---
>  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.
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.

Thanks,

> + if (err)
> + set_page_dirty(page);
> + } else {
> + set_page_dirty(page);
> + }
> +
> + f2fs_write_inode(inode, NULL);
> +
>   f2fs_put_page(page, 1);
>   f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
>   return copied;
> --
> 2.6.3
> 
> 
> --
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> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

RE: [f2fs-dev] [PATCH 1/2] f2fs: avoid multiple node page writes due to inline_data

2016-01-25 Thread Chao Yu 
Hi Jaegeuk,

> -Original Message-
> From: Jaegeuk Kim [mailto:jaeg...@kernel.org]
> Sent: Tuesday, January 26, 2016 3:18 AM
> To: Chao Yu
> Cc: linux-kernel@vger.kernel.org; linux-fsde...@vger.kernel.org;
> linux-f2fs-de...@lists.sourceforge.net
> Subject: Re: [f2fs-dev] [PATCH 1/2] f2fs: avoid multiple node page writes due 
> to inline_data
> 
> Hi Chao,
> 
> On Mon, Jan 25, 2016 at 05:42:40PM +0800, Chao Yu wrote:
> > Hi Jaegeuk,
> >
> > > -Original Message-
> > > From: Jaegeuk Kim [mailto:jaeg...@kernel.org]
> > > Sent: Sunday, January 24, 2016 4:16 AM
> > > To: linux-kernel@vger.kernel.org; linux-fsde...@vger.kernel.org;
> > > linux-f2fs-de...@lists.sourceforge.net
> > > 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 <jaeg...@kernel.org>
> > > ---
> > >  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 encountered deadlock issue, could you have a look at it?

==
 [ INFO: possible circular locking dependency detected ]
 4.5.0-rc1 #45 Tainted: G   O
 ---
 fstrim/15301 is trying to acquire lock:
  (sb_internal#2){..}, at: [] __sb_start_write+0xda/0xf0

 but task is already holding lock:
  (>cp_rwsem){..}, at: [] 
block_operations+0x82/0x130 [f2fs]

 which lock already depends on the new lock.


 the existing dependency chain (in reverse order) is:

 -> #1 (>cp_rwsem){..}:
[] lock_acquire+0xb7/0x130
[] down_read+0x39/0x50
[] f2fs_evict_inode+0x26f/0x370 [f2fs]
[] evict+0xdd/0x1d0
[] iput+0x19f/0x250
[] do_unlinkat+0x20d/0x310
[] SyS_unlinkat+0x22/0x40
[] entry_SYSCALL_64_fastpath+0x12/0x6f

 -> #0 (sb_internal#2){..}:
[] __lock_acquire+0x132b/0x1770
[] lock_acquire+0xb7/0x130
[] percpu_down_read+0x3c/0x80
[] __sb_start_write+0xda/0xf0
[] f2fs_evict_inode+0x221/0x370 [f2fs]
[] evict+0xdd/0x1d0
[] iput+0x19f/0x250
[] sync_node_pages+0x703/0x900 [f2fs]
[] block_operations+0x10a/0x130 [f2fs]
[] write_checkpoint+0xc4/0xb80 [f2fs]
[] f2fs_trim_fs+0x122/0x1d0 [f2fs]
[] f2fs_ioctl+0x7fa/0x9d0 [f2fs]
[] vfs_ioctl+0x18/0x40
[] do_vfs_ioctl+0x96/0x680
[] SyS_ioctl+0x92/0xa0
[] entry_SYSCALL_64_fastpath+0x12/0x6f

 other info that might help

Re: [f2fs-dev] [PATCH 1/2] f2fs: avoid multiple node page writes due to inline_data

2016-01-25 Thread Jaegeuk Kim 
Hi Chao,

On Mon, Jan 25, 2016 at 05:42:40PM +0800, Chao Yu wrote:
> Hi Jaegeuk,
> 
> > -Original Message-
> > From: Jaegeuk Kim [mailto:jaeg...@kernel.org]
> > Sent: Sunday, January 24, 2016 4:16 AM
> > To: linux-kernel@vger.kernel.org; linux-fsde...@vger.kernel.org;
> > linux-f2fs-de...@lists.sourceforge.net
> > 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 
> > ---
> >  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 
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 
---
 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();
} else {
err = f2fs_convert_inline_page(, 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();
+   clear_inline_node(dn.inode_page);
f2fs_put_dnode();
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

RE: [f2fs-dev] [PATCH 1/2] f2fs: avoid multiple node page writes due to inline_data

2016-01-25 Thread Chao Yu 
Hi Jaegeuk,

> -Original Message-
> From: Jaegeuk Kim [mailto:jaeg...@kernel.org]
> Sent: Sunday, January 24, 2016 4:16 AM
> To: linux-kernel@vger.kernel.org; linux-fsde...@vger.kernel.org;
> linux-f2fs-de...@lists.sourceforge.net
> 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 
> ---
>  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.
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.

Thanks,

> + if (err)
> + set_page_dirty(page);
> + } else {
> + set_page_dirty(page);
> + }
> +
> + f2fs_write_inode(inode, NULL);
> +
>   f2fs_put_page(page, 1);
>   f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
>   return copied;
> --
> 2.6.3
> 
> 
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