[PATCH 3/3] vfs: Add a trace point in the mark_inode_dirty function

Leann Ogasawara leann.ogasawara at canonical.com
Fri Sep 10 01:03:03 BST 2010


This patch doesn't apply cleanly to the current Ubuntu Maverick linux
kernel as it appears we're already carrying a version of this patch:

commit ce3cdc8812cc8a6f5645a9c372c7d6227676a7e5
Author: Arjan van de Ven <arjan at linux.intel.com>
Date:   Sun Oct 25 15:37:04 2009 -0700

    UBUNTU: SAUCE: vfs: Add a trace point in the mark_inode_dirty function

There's only a 1 line discrepancy (see below) between what we currently
have in the Maverick Ubuntu kernel and the patch inlined below.  Care to
re-send an updated patch to only add the additional one line change?
Care to also include your SOB on the patch?

Thanks,
Leann

On Thu, 2010-09-09 at 19:20 +0800, yong.shen at linaro.org wrote:
> From: Arjan van de Ven <arjan at linux.intel.com>
> 
> PowerTOP would like to be able to show who is keeping the disk
> busy by dirtying data. The most logical spot for this is in the vfs
> in the mark_inode_dirty() function, doing this on the block level
> is not possible because by the time the IO hits the block layer the
> guilty party can no longer be found ("kjournald" and "pdflush" are not
> useful answers to "who caused this file to be dirty).
> 
> The trace point follows the same logic/style as the block_dump code
> and pretty much dumps the same data, just not to dmesg (and thus to
> /var/log/messages) but via the trace events streams.
> 
> Signed-of-by: Arjan van de Ven <arjan at linux.intel.com>
> ---
>  fs/fs-writeback.c          |    4 +++
>  fs/inode.c                 |    4 +++
>  include/trace/events/vfs.h |   53 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 61 insertions(+), 0 deletions(-)
>  create mode 100644 include/trace/events/vfs.h
> 
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> index d5be169..6a2af1d 100644
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -26,6 +26,7 @@
>  #include <linux/blkdev.h>
>  #include <linux/backing-dev.h>
>  #include <linux/buffer_head.h>
> +#include <trace/events/vfs.h>
>  #include "internal.h"
>  
>  #define inode_to_bdi(inode)	((inode)->i_mapping->backing_dev_info)
> @@ -900,6 +901,9 @@ void __mark_inode_dirty(struct inode *inode, int flags)
>  			sb->s_op->dirty_inode(inode);
>  	}
>  
> +	if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES))

Looks like the above line is the only additional change from what we
already have.

> +		trace_dirty_inode(inode, current);
> +
>  	/*
>  	 * make sure that changes are seen by all cpus before we test i_state
>  	 * -- mikulas
> diff --git a/fs/inode.c b/fs/inode.c
> index 722860b..a06184f 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -1626,3 +1626,7 @@ void inode_init_owner(struct inode *inode, const struct inode *dir,
>  	inode->i_mode = mode;
>  }
>  EXPORT_SYMBOL(inode_init_owner);
> +
> +#define CREATE_TRACE_POINTS  
> +#include <trace/events/vfs.h>
> +
> diff --git a/include/trace/events/vfs.h b/include/trace/events/vfs.h
> new file mode 100644
> index 0000000..21cf9fb
> --- /dev/null
> +++ b/include/trace/events/vfs.h
> @@ -0,0 +1,53 @@
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM vfs
> +
> +#if !defined(_TRACE_VFS_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_VFS_H
> +
> +/*
> + * Tracepoint for dirtying an inode:
> + */
> +TRACE_EVENT(dirty_inode,
> +
> +	TP_PROTO(struct inode *inode, struct task_struct *task),
> +
> +	TP_ARGS(inode, task),
> +
> +	TP_STRUCT__entry(
> +		__array( char,	comm,	TASK_COMM_LEN	)
> +		__field( pid_t,	pid			)
> +		__array( char,  dev,    16		)
> +		__array( char,  file,   32		)
> +	),
> +
> +	TP_fast_assign(
> +		if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) {
> +                	struct dentry *dentry;
> +                	const char *name = "?";
> +
> +			dentry = d_find_alias(inode);
> +			if (dentry) {
> +				spin_lock(&dentry->d_lock);
> +				name = (const char *) dentry->d_name.name;
> +			}
> +
> +			memcpy(__entry->comm, task->comm, TASK_COMM_LEN);
> +			__entry->pid = task->pid;
> +			strlcpy(__entry->file, name, 32);
> +			strlcpy(__entry->dev, inode->i_sb->s_id, 16);
> +
> +			if (dentry) {
> +				spin_unlock(&dentry->d_lock);
> +				dput(dentry);
> +			}
> +		}
> +	),
> +
> +	TP_printk("task=%i (%s) file=%s dev=%s",
> +		__entry->pid, __entry->comm, __entry->file, __entry->dev)
> +);
> +
> +#endif /* _TRACE_VFS_H */
> +
> +/* This part must be outside protection */
> +#include <trace/define_trace.h>
> -- 
> 1.6.3.3
> 
> 





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