On Fri, Mar 02, 2018 at 09:34:02AM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@xxxxxxxxxx>
>
> Noticed when looking at why cycling 600k inodes/s through the inode
> cache was taking a total of 8% cpu in memset() during inode
> initialisation. There is no need to zero the inode.i_data structure
> twice.
>
> This increases single threaded bulkstat throughput from ~200,000
> inodes/s to ~220,000 inodes/s, so we save a substantial amount of
> CPU time per inode init by doing this.
>
> Signed-Off-By: Dave Chinner <dchinner@xxxxxxxxxx>
Looks good to me.
Reviewed-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx>
> ---
> fs/inode.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/fs/inode.c b/fs/inode.c
> index 6295f1415761..b153aeaa61ea 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -346,9 +346,8 @@ void inc_nlink(struct inode *inode)
> }
> EXPORT_SYMBOL(inc_nlink);
>
> -void address_space_init_once(struct address_space *mapping)
> +static void __address_space_init_once(struct address_space *mapping)
> {
> - memset(mapping, 0, sizeof(*mapping));
> INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC | __GFP_ACCOUNT);
> spin_lock_init(&mapping->tree_lock);
> init_rwsem(&mapping->i_mmap_rwsem);
> @@ -356,6 +355,12 @@ void address_space_init_once(struct address_space *mapping)
> spin_lock_init(&mapping->private_lock);
> mapping->i_mmap = RB_ROOT_CACHED;
> }
> +
> +void address_space_init_once(struct address_space *mapping)
> +{
> + memset(mapping, 0, sizeof(*mapping));
> + __address_space_init_once(mapping);
> +}
> EXPORT_SYMBOL(address_space_init_once);
>
> /*
> @@ -371,7 +376,7 @@ void inode_init_once(struct inode *inode)
> INIT_LIST_HEAD(&inode->i_io_list);
> INIT_LIST_HEAD(&inode->i_wb_list);
> INIT_LIST_HEAD(&inode->i_lru);
> - address_space_init_once(&inode->i_data);
> + __address_space_init_once(&inode->i_data);
> i_size_ordered_init(inode);
> }
> EXPORT_SYMBOL(inode_init_once);
> --
> 2.16.1
>
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--
Carlos
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