On Sun, Sep 23, 2012 at 08:56:31PM +0800, zwu.kernel@xxxxxxxxx wrote:
> From: Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx>
>
> Miscellaneous features that implement hot data tracking
> and generally make the hot data functions a bit more friendly.
>
> Signed-off-by: Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx>
> ---
> 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.
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);
}
> 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...
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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