inode: don't memset the inode address space twice (ae23395d) · Commits · 戴 / test

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@redhat.com> Reviewed-by:

Jan Kara <jack@suse.cz> Reviewed-by:

Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by:

Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by:

Darrick J. Wong <darrick.wong@oracle.com>

fs/inode.c

+8 −3

Original line number	Diff line number	Diff line
		@@ -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);

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