The dellaloc work is not frequently used, the delayed status is once set
and read so it looks quite safe to drop the member and store the status
in the lowest bit of the inode pointer.
Combined with the removal of 'wait' we got +2 objects per 4k slab.
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
---
fs/btrfs/ctree.h | 5 ++++-
fs/btrfs/inode.c | 11 +++++++++--
2 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index a61c53bce162..d5e250a65725 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3901,8 +3901,11 @@ void btrfs_extent_item_to_extent_map(struct inode *inode,
/* inode.c */
struct btrfs_delalloc_work {
+ /*
+ * Note: lowest bit of inode tracks if the iput is delayed,
+ * do not access the pointer directly.
+ */
struct inode *inode;
- int delay_iput;
struct completion completion;
struct list_head list;
struct btrfs_work work;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 15b29e879ffc..529a53b80ca0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -9436,16 +9436,21 @@ static void btrfs_run_delalloc_work(struct btrfs_work *work)
{
struct btrfs_delalloc_work *delalloc_work;
struct inode *inode;
+ int delay_iput;
delalloc_work = container_of(work, struct btrfs_delalloc_work,
work);
inode = delalloc_work->inode;
+ /* Lowest bit of inode pointer tracks the delayed status */
+ delay_iput = ((unsigned long)inode & 1UL);
+ inode = (struct inode *)((unsigned long)inode & ~1UL);
+
filemap_flush(inode->i_mapping);
if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
&BTRFS_I(inode)->runtime_flags))
filemap_flush(inode->i_mapping);
- if (delalloc_work->delay_iput)
+ if (delay_iput)
btrfs_add_delayed_iput(inode);
else
iput(inode);
@@ -9464,7 +9469,9 @@ struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
init_completion(&work->completion);
INIT_LIST_HEAD(&work->list);
work->inode = inode;
- work->delay_iput = delay_iput;
+ /* Lowest bit of inode pointer tracks the delayed status */
+ if (delay_iput)
+ *((unsigned long *)work->inode) |= 1UL;
WARN_ON_ONCE(!inode);
btrfs_init_work(&work->work, btrfs_flush_delalloc_helper,
btrfs_run_delalloc_work, NULL, NULL);
--
2.6.2
--
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