| Message ID | 1536860682-41012-1-git-send-email-bo.liu@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] Btrfs: skip set_page_dirty if eb is dirty | expand |
On 13.09.2018 20:44, Liu Bo wrote: > As long as @eb is marked with EXTENT_BUFFER_DIRTY, all of its pages > are dirty, so no need to set pages dirty again. > > Ftrace showed that the loop took 10us on my dev box, so removing this > can save us at least 10us if eb is already dirty. > > Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> > --- > v2: Update the patch's description. > > fs/btrfs/extent_io.c | 11 +++++++---- > fs/btrfs/extent_io.h | 2 +- > 2 files changed, 8 insertions(+), 5 deletions(-) > > diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c > index 628f1aef34b0..fb2bf50134a1 100644 > --- a/fs/btrfs/extent_io.c > +++ b/fs/btrfs/extent_io.c > @@ -5165,11 +5165,11 @@ void clear_extent_buffer_dirty(struct extent_buffer *eb) > WARN_ON(atomic_read(&eb->refs) == 0); > } > > -int set_extent_buffer_dirty(struct extent_buffer *eb) > +bool set_extent_buffer_dirty(struct extent_buffer *eb) > { > int i; > int num_pages; > - int was_dirty = 0; > + bool was_dirty; > > check_buffer_tree_ref(eb); > > @@ -5179,8 +5179,11 @@ int set_extent_buffer_dirty(struct extent_buffer *eb) > WARN_ON(atomic_read(&eb->refs) == 0); > WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)); > > - for (i = 0; i < num_pages; i++) > - set_page_dirty(eb->pages[i]); > + if (!was_dirty) { > + for (i = 0; i < num_pages; i++) > + set_page_dirty(eb->pages[i]); > + } > + > return was_dirty; > } > > diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h > index b4d03e677e1d..f2ab42d57f02 100644 > --- a/fs/btrfs/extent_io.h > +++ b/fs/btrfs/extent_io.h > @@ -479,7 +479,7 @@ void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start, > void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start, > unsigned long pos, unsigned long len); > void clear_extent_buffer_dirty(struct extent_buffer *eb); > -int set_extent_buffer_dirty(struct extent_buffer *eb); > +bool set_extent_buffer_dirty(struct extent_buffer *eb); > void set_extent_buffer_uptodate(struct extent_buffer *eb); > void clear_extent_buffer_uptodate(struct extent_buffer *eb); > int extent_buffer_under_io(struct extent_buffer *eb); >
On Fri, Sep 14, 2018 at 01:44:42AM +0800, Liu Bo wrote: > As long as @eb is marked with EXTENT_BUFFER_DIRTY, all of its pages > are dirty, so no need to set pages dirty again. > > Ftrace showed that the loop took 10us on my dev box, so removing this > can save us at least 10us if eb is already dirty. > > Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com> Reviewed-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 628f1aef34b0..fb2bf50134a1 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -5165,11 +5165,11 @@ void clear_extent_buffer_dirty(struct extent_buffer *eb) WARN_ON(atomic_read(&eb->refs) == 0); } -int set_extent_buffer_dirty(struct extent_buffer *eb) +bool set_extent_buffer_dirty(struct extent_buffer *eb) { int i; int num_pages; - int was_dirty = 0; + bool was_dirty; check_buffer_tree_ref(eb); @@ -5179,8 +5179,11 @@ int set_extent_buffer_dirty(struct extent_buffer *eb) WARN_ON(atomic_read(&eb->refs) == 0); WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)); - for (i = 0; i < num_pages; i++) - set_page_dirty(eb->pages[i]); + if (!was_dirty) { + for (i = 0; i < num_pages; i++) + set_page_dirty(eb->pages[i]); + } + return was_dirty; } diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h index b4d03e677e1d..f2ab42d57f02 100644 --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h @@ -479,7 +479,7 @@ void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start, void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start, unsigned long pos, unsigned long len); void clear_extent_buffer_dirty(struct extent_buffer *eb); -int set_extent_buffer_dirty(struct extent_buffer *eb); +bool set_extent_buffer_dirty(struct extent_buffer *eb); void set_extent_buffer_uptodate(struct extent_buffer *eb); void clear_extent_buffer_uptodate(struct extent_buffer *eb); int extent_buffer_under_io(struct extent_buffer *eb);
As long as @eb is marked with EXTENT_BUFFER_DIRTY, all of its pages are dirty, so no need to set pages dirty again. Ftrace showed that the loop took 10us on my dev box, so removing this can save us at least 10us if eb is already dirty. Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com> --- v2: Update the patch's description. fs/btrfs/extent_io.c | 11 +++++++---- fs/btrfs/extent_io.h | 2 +- 2 files changed, 8 insertions(+), 5 deletions(-)