Re: [PATCH v2 3/7] f2fs: add tracepoint for tracing the page i/o operations

From: Namjae Jeon
Date: Sun Mar 17 2013 - 19:59:32 EST


2013/3/17, Steven Rostedt <rostedt@xxxxxxxxxxx>:
> On Sun, 2013-03-17 at 17:40 +0900, Namjae Jeon wrote:
>> From: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
>>
>> Add tracepoints for page i/o operations and block allocation
>> tracing during page read operation.
>>
>> Signed-off-by: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
>> Signed-off-by: Pankaj Kumar <pankaj.km@xxxxxxxxxxx>
>> ---
>> fs/f2fs/data.c | 11 ++++++--
>> include/trace/events/f2fs.h | 58
>> +++++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 67 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>> index 02ad450..bb9117b 100644
>> --- a/fs/f2fs/data.c
>> +++ b/fs/f2fs/data.c
>> @@ -22,6 +22,7 @@
>> #include "f2fs.h"
>> #include "node.h"
>> #include "segment.h"
>> +#include <trace/events/f2fs.h>
>>
>> /*
>> * Lock ordering for the change of data block address:
>> @@ -335,6 +336,9 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct
>> page *page,
>> bool sync = (type == READ_SYNC);
>> struct bio *bio;
>>
>> + if (page->mapping)
>> + trace_f2fs_readpage(page);
>
> Since the only thing that happens whet page->mapping is set is to trace
> the page, you can move that check into the tracepoint itself. That is,
> move the branch into the tracepoint, making the branch a nop when the
> tracepoint isn't active. That's what TRACE_EVENT_CONDITION() does. Make
> this into:
>
> trace_f2fs_readpage(page);
>
> and then see below.
>
>> +
>> /* This page can be already read by other threads */
>> if (PageUptodate(page)) {
>> if (!sync)
>> @@ -385,6 +389,7 @@ static int get_data_block_ro(struct inode *inode,
>> sector_t iblock,
>> pgoff_t pgofs;
>> int err;
>>
>> + trace_f2fs_get_data_block_enter(inode, iblock, 0);
>> /* Get the page offset from the block offset(iblock) */
>> pgofs = (pgoff_t)(iblock >> (PAGE_CACHE_SHIFT - blkbits));
>>
>> @@ -394,9 +399,10 @@ static int get_data_block_ro(struct inode *inode,
>> sector_t iblock,
>> /* When reading holes, we need its node page */
>> set_new_dnode(&dn, inode, NULL, NULL, 0);
>> err = get_dnode_of_data(&dn, pgofs, LOOKUP_NODE_RA);
>> - if (err)
>> + if (err) {
>> + trace_f2fs_get_data_block_exit(inode, iblock, err);
>> return (err == -ENOENT) ? 0 : err;
>> -
>> + }
>> /* It does not support data allocation */
>> BUG_ON(create);
>>
>> @@ -420,6 +426,7 @@ static int get_data_block_ro(struct inode *inode,
>> sector_t iblock,
>> bh_result->b_size = (i << blkbits);
>> }
>> f2fs_put_dnode(&dn);
>> + trace_f2fs_get_data_block_exit(inode, iblock, 0);
>> return 0;
>> }
>>
>> diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
>> index 0d39f58..d60f3ed 100644
>> --- a/include/trace/events/f2fs.h
>> +++ b/include/trace/events/f2fs.h
>> @@ -266,6 +266,64 @@ TRACE_EVENT(f2fs_truncate,
>> (unsigned long) __entry->ino)
>> );
>>
>> +TRACE_EVENT(f2fs_readpage,
>
> TRACE_EVENT_CONDITIO(f2fs_readpage,
>
>> + TP_PROTO(struct page *page),
>> +
>> + TP_ARGS(page),
>
> TP_CONDITION(page->mapping),
>
> That's it!
>
> Now the tracepoint will only be called if page->mapping is set, but
> checking page->mapping will be done only if the tracepoint is enabled.
> Keeping the original code untouched.
Hi Steve.
Okay :) I will fix it. Thanks for your review !
>
> -- Steve
>
>> +
>> + TP_STRUCT__entry(
>> + __field(pgoff_t, index)
>> + __field(ino_t, ino)
>> + __field(dev_t, dev)
>> +
>> + ),
>> +
>> + TP_fast_assign(
>> + __entry->index = page->index;
>> + __entry->ino = page->mapping->host->i_ino;
>> + __entry->dev = page->mapping->host->i_sb->s_dev;
>> + ),
>> +
>> + TP_printk("dev %d,%d ino %lu page_index %lu",
>> + MAJOR(__entry->dev), MINOR(__entry->dev),
>> + (unsigned long) __entry->ino,
>> + (unsigned long) __entry->index)
>> +);
>> +
>> +DECLARE_EVENT_CLASS(f2fs_data_block,
>> + TP_PROTO(struct inode *inode, sector_t block, int ret),
>> +
>> + TP_ARGS(inode, block, ret),
>> +
>> + TP_STRUCT__entry(
>> + __field(dev_t, dev)
>> + __field(ino_t, ino)
>> + __field(sector_t, block)
>> + __field(int, ret)
>> + ),
>> +
>> + TP_fast_assign(
>> + __entry->dev = inode->i_sb->s_dev;
>> + __entry->ino = inode->i_ino;
>> + __entry->block = block;
>> + __entry->ret = ret;
>> + ),
>> +
>> + TP_printk("dev %d,%d ino %lu block number %llu error %d",
>> + MAJOR(__entry->dev), MINOR(__entry->dev),
>> + (unsigned long) __entry->ino, (unsigned long long) __entry->block,
>> __entry->ret)
>> +);
>> +
>> +DEFINE_EVENT(f2fs_data_block, f2fs_get_data_block_enter,
>> + TP_PROTO(struct inode *inode, sector_t block, int ret),
>> + TP_ARGS(inode, block, ret)
>> +);
>> +
>> +DEFINE_EVENT(f2fs_data_block, f2fs_get_data_block_exit,
>> + TP_PROTO(struct inode *inode, sector_t block, int ret),
>> + TP_ARGS(inode, block, ret)
>> +);
>> +
>> #endif /* _TRACE_F2FS_H */
>>
>> /* This part must be outside protection */
>
>
>
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