On Thu, Sep 27, 2012 at 11:54 AM, Dave Chinner [off-list ref] wrote:

On Sun, Sep 23, 2012 at 08:56:31PM +0800, zwu.kernel@gmail.com wrote:

quoted

From: Zhi Yong Wu <redacted>

  Miscellaneous features that implement hot data tracking
and generally make the hot data functions a bit more friendly.

Signed-off-by: Zhi Yong Wu <redacted>
---
 fs/direct-io.c               |   10 ++++++++++
 include/linux/hot_tracking.h |   11 +++++++++++
 mm/filemap.c                 |    8 ++++++++
 mm/page-writeback.c          |   21 +++++++++++++++++++++
 mm/readahead.c               |    9 +++++++++
 5 files changed, 59 insertions(+), 0 deletions(-)

diff --git a/fs/direct-io.c b/fs/direct-io.c
index f86c720..3773f44 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c

@@ -37,6 +37,7 @@
 #include <linux/uio.h>
 #include <linux/atomic.h>
 #include <linux/prefetch.h>
+#include "hot_tracking.h"

 /*
  * How many user pages to map in one call to get_user_pages().  This determines

@@ -1297,6 +1298,15 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
      prefetch(bdev->bd_queue);
      prefetch((char *)bdev->bd_queue + SMP_CACHE_BYTES);

+     /* Hot data tracking */
+     if (TRACK_THIS_INODE(iocb->ki_filp->f_mapping->host)
+                     && iov_length(iov, nr_segs) > 0) {
+             hot_rb_update_freqs(iocb->ki_filp->f_mapping->host,
+                             (u64)offset,
+                             (u64)iov_length(iov, nr_segs),
+                             rw & WRITE);
+     }

That's a bit messy. I'd prefer a static inline function that hides
all this. e.g.

Do you think of moving the condition into hot_inode_udate_freqs(), not
adding another new function?

track_hot_inode_ranges(inode, offset, length, rw)
{
        if (inode->i_sb->s_flags & MS_HOT_TRACKING)
                hot_inode_freq_update(inode, offset, length, rw);
}

quoted

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 5ad5ce2..552c861 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c

@@ -35,6 +35,7 @@
 #include <linux/buffer_head.h> /* __set_page_dirty_buffers */
 #include <linux/pagevec.h>
 #include <linux/timer.h>
+#include <linux/hot_tracking.h>
 #include <trace/events/writeback.h>

 /*

@@ -1895,13 +1896,33 @@ EXPORT_SYMBOL(generic_writepages);
 int do_writepages(struct address_space *mapping, struct writeback_control *wbc)
 {
      int ret;
+     pgoff_t start = 0;
+     u64 prev_count = 0, count = 0;

      if (wbc->nr_to_write <= 0)
              return 0;
+
+     /* Hot data tracking */
+     if (TRACK_THIS_INODE(mapping->host)
+             && wbc->range_cyclic) {
+             start = mapping->writeback_index << PAGE_CACHE_SHIFT;
+             prev_count = (u64)wbc->nr_to_write;
+     }

Why only wbc->range_cyclic? This won't record things like
synchronous writes or fsync-triggered writes, are are far more
likely to be to hot ranges in a file...

sorry, i don't undersand what  wbc->range_cyclic means. OK, i will fix
it in next version.

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com

-- 
Regards,

Zhi Yong Wu