On Tue, Dec 26, 2017 at 07:54:40PM +0300, Kirill A. Shutemov wrote:
> On Fri, Dec 15, 2017 at 02:03:35PM -0800, Matthew Wilcox wrote:
> > From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
> >
> > This results in no change in structure size on 64-bit x86 as it fits in
> > the padding between the gfp_t and the void *.
>
> The patch does more than described in the subject and commit message. At first
> I was confused why do you need to touch idr here. It took few minutes to figure
> it out.
>
> Could you please add more into commit message about lockname and xa_ locking
> interface since you introduce it here?
Sure! How's this?
xarray: Add the xa_lock to the radix_tree_root
This results in no change in structure size on 64-bit x86 as it fits in
the padding between the gfp_t and the void *.
Initialising the spinlock requires a name for the benefit of lockdep,
so RADIX_TREE_INIT() now needs to know the name of the radix tree it's
initialising, and so do IDR_INIT() and IDA_INIT().
Also add the xa_lock() and xa_unlock() family of wrappers to make it
easier to use the lock. If we could rely on -fplan9-extensions in
the compiler, we could avoid all of this syntactic sugar, but that
wasn't added until gcc 4.6.
