From f6a47f9fc4dc4bb486cdac6443a58b84d23021b3 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Mon, 30 Nov 2015 16:51:29 +0100 Subject: [PATCH] btrfs: better packing of btrfs_delayed_extent_op btrfs_delayed_extent_op can be packed in a better way, it's 40 bytes now and has 8 unused bytes. Reducing the level type to u8 makes it possible to squeeze it to the padding byte after key. The bitfields were switched to bool as there's space to store the full byte without increasing the whole structure, besides that the generated assembly is smaller. struct btrfs_delayed_extent_op { struct btrfs_disk_key key; /* 0 17 */ u8 level; /* 17 1 */ bool update_key; /* 18 1 */ bool update_flags; /* 19 1 */ bool is_data; /* 20 1 */ /* XXX 3 bytes hole, try to pack */ u64 flags_to_set; /* 24 8 */ /* size: 32, cachelines: 1, members: 6 */ /* sum members: 29, holes: 1, sum holes: 3 */ /* last cacheline: 32 bytes */ }; The final size is 32 bytes which gives +26 object per slab page. text data bss dec hex filename 938811 43670 23144 1005625 f5839 fs/btrfs/btrfs.ko.before 938747 43670 23144 1005561 f57f9 fs/btrfs/btrfs.ko.after Signed-off-by: David Sterba (cherry picked from commit 35b3ad50baa4a5fc2ae616c0513d2987bfb52a85) --- fs/btrfs/delayed-ref.c | 4 ++-- fs/btrfs/delayed-ref.h | 8 ++++---- fs/btrfs/extent-tree.c | 15 ++++++--------- 3 files changed, 12 insertions(+), 15 deletions(-) diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c index 8f8ed7d20bac5..8edb3f518caf6 100644 --- a/fs/btrfs/delayed-ref.c +++ b/fs/btrfs/delayed-ref.c @@ -528,12 +528,12 @@ update_existing_head_ref(struct btrfs_delayed_ref_root *delayed_refs, memcpy(&existing_ref->extent_op->key, &ref->extent_op->key, sizeof(ref->extent_op->key)); - existing_ref->extent_op->update_key = 1; + existing_ref->extent_op->update_key = true; } if (ref->extent_op->update_flags) { existing_ref->extent_op->flags_to_set |= ref->extent_op->flags_to_set; - existing_ref->extent_op->update_flags = 1; + existing_ref->extent_op->update_flags = true; } btrfs_free_delayed_extent_op(ref->extent_op); } diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h index 5eb0892396d01..74888239c4694 100644 --- a/fs/btrfs/delayed-ref.h +++ b/fs/btrfs/delayed-ref.h @@ -60,11 +60,11 @@ struct btrfs_delayed_ref_node { struct btrfs_delayed_extent_op { struct btrfs_disk_key key; + u8 level; + bool update_key; + bool update_flags; + bool is_data; u64 flags_to_set; - int level; - unsigned int update_key:1; - unsigned int update_flags:1; - unsigned int is_data:1; }; /* diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 3f572e48e755b..6e20a69befd56 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -2957,9 +2957,9 @@ int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans, return -ENOMEM; extent_op->flags_to_set = flags; - extent_op->update_flags = 1; - extent_op->update_key = 0; - extent_op->is_data = is_data ? 1 : 0; + extent_op->update_flags = true; + extent_op->update_key = false; + extent_op->is_data = is_data ? true : false; extent_op->level = level; ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr, @@ -8085,12 +8085,9 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans, else memset(&extent_op->key, 0, sizeof(extent_op->key)); extent_op->flags_to_set = flags; - if (skinny_metadata) - extent_op->update_key = 0; - else - extent_op->update_key = 1; - extent_op->update_flags = 1; - extent_op->is_data = 0; + extent_op->update_key = skinny_metadata ? false : true; + extent_op->update_flags = true; + extent_op->is_data = false; extent_op->level = level; ret = btrfs_add_delayed_tree_ref(root->fs_info, trans, -- 2.53.0