Patchwork [v2,2/8] ext4: Add new data structures and related functions to count io types

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Submitter Zheng Liu
Date Nov. 10, 2011, 10:34 a.m.
Message ID <1320921294-30321-3-git-send-email-wenqing.lz@taobao.com>
Download mbox | patch
Permalink /patch/124846/
State Superseded
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Comments

Zheng Liu - Nov. 10, 2011, 10:34 a.m.
From: Zheng Liu <wenqing.lz@taobao.com>

A per-cpu counter is defined to store io types in ext4. We define 10 io types
in ext4, which includes 9 metadata types and 1 data type. Read and write
operations are counted separately. When checks 'Issue' flag, filesystem needs
to lock buffer.

Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Wang Shaoyan <wangshaoyan.pt@taobao.com>
---
 fs/ext4/ext4.h  |   53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/ext4/super.c |   19 +++++++++++++++++++
 2 files changed, 72 insertions(+), 0 deletions(-)
Steven Whitehouse - Nov. 11, 2011, 10:58 a.m.
Hi,

On Thu, 2011-11-10 at 18:34 +0800, Zheng Liu wrote:
> From: Zheng Liu <wenqing.lz@taobao.com>
> 
> A per-cpu counter is defined to store io types in ext4. We define 10 io types
> in ext4, which includes 9 metadata types and 1 data type. Read and write
> operations are counted separately. When checks 'Issue' flag, filesystem needs
> to lock buffer.
> 
> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
> Signed-off-by: Wang Shaoyan <wangshaoyan.pt@taobao.com>
> ---
>  fs/ext4/ext4.h  |   53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  fs/ext4/super.c |   19 +++++++++++++++++++
>  2 files changed, 72 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 5b0e26a..39a1495 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -1108,6 +1108,23 @@ struct ext4_super_block {
>  #define EXT4_MF_FS_ABORTED	0x0002	/* Fatal error detected */
>  
>  /*
> + * ext4 io types
> + */
> +enum {
> +	EXT4_IOS_SUPER_BLOCK = 0,
> +	EXT4_IOS_GROUP_DESC,
> +	EXT4_IOS_INODE_BITMAP,
> +	EXT4_IOS_BLOCK_BITMAP,
> +	EXT4_IOS_INODE_TABLE,
> +	EXT4_IOS_EXTENT_BLOCK,
> +	EXT4_IOS_INDIRECT_BLOCK,
> +	EXT4_IOS_DIR_ENTRY,
> +	EXT4_IOS_EXTENDED_ATTR,
> +	EXT4_IOS_REGULAR_DATA,
> +	EXT4_IOS_TYPE_END,
> +};
> +
> +/*
>   * fourth extended-fs super-block data in memory
>   */
>  struct ext4_sb_info {
> @@ -1284,6 +1301,11 @@ static inline void ext4_set_io_unwritten_flag(struct inode *inode,
>  	}
>  }
>  
> +static inline unsigned ext4_blocks_per_page(struct inode *inode)
> +{
> +	return PAGE_CACHE_SIZE >> inode->i_blkbits;
> +}
> +
>  /*
>   * Inode dynamic state flags
>   */
> @@ -1926,6 +1948,37 @@ extern int ext4_group_extend(struct super_block *sb,
>  				ext4_fsblk_t n_blocks_count);
>  
>  /* super.c */
> +extern void __ext4_io_stat(int, int, unsigned long);
> +#define ext4_ios_read(bh, type, count)					\
> +	do {								\
> +		if (!bh)						\
> +			break;						\
> +		lock_buffer(bh);					\
> +		if (buffer_issue(bh)) {					\
> +			clear_buffer_issue(bh);				\
> +			__ext4_io_stat(READ, type, count);		\
> +		}							\
> +		unlock_buffer(bh);					\
> +	} while (0)
Why not just test_and_clear_bit(BH_Issue) ? I don't follow why the
buffer needs to be locked and unlocked,

Steve.


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Zheng Liu - Nov. 11, 2011, 3:45 p.m.
On Fri, Nov 11, 2011 at 10:58:11AM +0000, Steven Whitehouse wrote:
> Hi,
> 
> On Thu, 2011-11-10 at 18:34 +0800, Zheng Liu wrote:
> > From: Zheng Liu <wenqing.lz@taobao.com>
> > 
> > A per-cpu counter is defined to store io types in ext4. We define 10 io types
> > in ext4, which includes 9 metadata types and 1 data type. Read and write
> > operations are counted separately. When checks 'Issue' flag, filesystem needs
> > to lock buffer.
> > 
> > Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
> > Signed-off-by: Wang Shaoyan <wangshaoyan.pt@taobao.com>
> > ---
> >  fs/ext4/ext4.h  |   53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  fs/ext4/super.c |   19 +++++++++++++++++++
> >  2 files changed, 72 insertions(+), 0 deletions(-)
> > 
> > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> > index 5b0e26a..39a1495 100644
> > --- a/fs/ext4/ext4.h
> > +++ b/fs/ext4/ext4.h
> > @@ -1108,6 +1108,23 @@ struct ext4_super_block {
> >  #define EXT4_MF_FS_ABORTED	0x0002	/* Fatal error detected */
> >  
> >  /*
> > + * ext4 io types
> > + */
> > +enum {
> > +	EXT4_IOS_SUPER_BLOCK = 0,
> > +	EXT4_IOS_GROUP_DESC,
> > +	EXT4_IOS_INODE_BITMAP,
> > +	EXT4_IOS_BLOCK_BITMAP,
> > +	EXT4_IOS_INODE_TABLE,
> > +	EXT4_IOS_EXTENT_BLOCK,
> > +	EXT4_IOS_INDIRECT_BLOCK,
> > +	EXT4_IOS_DIR_ENTRY,
> > +	EXT4_IOS_EXTENDED_ATTR,
> > +	EXT4_IOS_REGULAR_DATA,
> > +	EXT4_IOS_TYPE_END,
> > +};
> > +
> > +/*
> >   * fourth extended-fs super-block data in memory
> >   */
> >  struct ext4_sb_info {
> > @@ -1284,6 +1301,11 @@ static inline void ext4_set_io_unwritten_flag(struct inode *inode,
> >  	}
> >  }
> >  
> > +static inline unsigned ext4_blocks_per_page(struct inode *inode)
> > +{
> > +	return PAGE_CACHE_SIZE >> inode->i_blkbits;
> > +}
> > +
> >  /*
> >   * Inode dynamic state flags
> >   */
> > @@ -1926,6 +1948,37 @@ extern int ext4_group_extend(struct super_block *sb,
> >  				ext4_fsblk_t n_blocks_count);
> >  
> >  /* super.c */
> > +extern void __ext4_io_stat(int, int, unsigned long);
> > +#define ext4_ios_read(bh, type, count)					\
> > +	do {								\
> > +		if (!bh)						\
> > +			break;						\
> > +		lock_buffer(bh);					\
> > +		if (buffer_issue(bh)) {					\
> > +			clear_buffer_issue(bh);				\
> > +			__ext4_io_stat(READ, type, count);		\
> > +		}							\
> > +		unlock_buffer(bh);					\
> > +	} while (0)
> Why not just test_and_clear_bit(BH_Issue) ? I don't follow why the
> buffer needs to be locked and unlocked,

test_and_clear_bit(BH_Issue) is better. Calling lock/unlock_buffer() is
to ensure 'Issue' flag can be set or cleared atomically. It is
unnecessary after using test_and_clear_bit(BH_Issue).

Regards,
Zheng

> 
> Steve.
> 
> 
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Patch

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 5b0e26a..39a1495 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1108,6 +1108,23 @@  struct ext4_super_block {
 #define EXT4_MF_FS_ABORTED	0x0002	/* Fatal error detected */
 
 /*
+ * ext4 io types
+ */
+enum {
+	EXT4_IOS_SUPER_BLOCK = 0,
+	EXT4_IOS_GROUP_DESC,
+	EXT4_IOS_INODE_BITMAP,
+	EXT4_IOS_BLOCK_BITMAP,
+	EXT4_IOS_INODE_TABLE,
+	EXT4_IOS_EXTENT_BLOCK,
+	EXT4_IOS_INDIRECT_BLOCK,
+	EXT4_IOS_DIR_ENTRY,
+	EXT4_IOS_EXTENDED_ATTR,
+	EXT4_IOS_REGULAR_DATA,
+	EXT4_IOS_TYPE_END,
+};
+
+/*
  * fourth extended-fs super-block data in memory
  */
 struct ext4_sb_info {
@@ -1284,6 +1301,11 @@  static inline void ext4_set_io_unwritten_flag(struct inode *inode,
 	}
 }
 
+static inline unsigned ext4_blocks_per_page(struct inode *inode)
+{
+	return PAGE_CACHE_SIZE >> inode->i_blkbits;
+}
+
 /*
  * Inode dynamic state flags
  */
@@ -1926,6 +1948,37 @@  extern int ext4_group_extend(struct super_block *sb,
 				ext4_fsblk_t n_blocks_count);
 
 /* super.c */
+extern void __ext4_io_stat(int, int, unsigned long);
+#define ext4_ios_read(bh, type, count)					\
+	do {								\
+		if (!bh)						\
+			break;						\
+		lock_buffer(bh);					\
+		if (buffer_issue(bh)) {					\
+			clear_buffer_issue(bh);				\
+			__ext4_io_stat(READ, type, count);		\
+		}							\
+		unlock_buffer(bh);					\
+	} while (0)
+#define ext4_ios_write(handle, bh, type, count)				\
+	do {								\
+		if (!bh) {						\
+			__ext4_io_stat(WRITE, type, count);		\
+			break;						\
+		}							\
+		if (!handle || !ext4_handle_valid(handle)) {		\
+			if (buffer_dirty(bh))				\
+				break;					\
+		} else {						\
+			if (buffer_jbddirty(bh))			\
+				break;					\
+		}							\
+		__ext4_io_stat(WRITE, type, count);			\
+	} while(0)
+#define ext4_ios_read_one(bh, type)	ext4_ios_read(bh, type, 1)
+#define ext4_ios_write_one(handle, bh, type) \
+	ext4_ios_write(handle, bh, type, 1)
+
 extern void *ext4_kvmalloc(size_t size, gfp_t flags);
 extern void *ext4_kvzalloc(size_t size, gfp_t flags);
 extern void ext4_kvfree(void *ptr);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9953d80..3bec50c 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4940,6 +4940,25 @@  out:
 
 #endif
 
+static DEFINE_PER_CPU(unsigned long [EXT4_IOS_TYPE_END][2], ext4_ios_counters);
+
+static inline unsigned long ext4_get_ios_counter(int rw, int type)
+{
+	unsigned long sum = 0;
+	int i;
+
+	for_each_possible_cpu(i)
+		sum += per_cpu(ext4_ios_counters[type][rw], i);
+
+	return sum;
+}
+
+void __ext4_io_stat(int rw, int type, unsigned long count)
+{
+	BUG_ON(type < 0 || type >= EXT4_IOS_TYPE_END);
+	this_cpu_add(ext4_ios_counters[type][rw], count);
+}
+
 static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
 		       const char *dev_name, void *data)
 {