Thread (95 messages) 95 messages, 4 authors, 2018-01-03

Re: [PATCH v5 03/78] xarray: Add the xa_lock to the radix_tree_root

From: Kirill A. Shutemov <hidden>
Date: 2017-12-27 10:17:18
Also in: linux-f2fs-devel, linux-fsdevel, linux-mm, linux-usb, linux-xfs, lkml

On Tue, Dec 26, 2017 at 07:43:40PM -0800, Matthew Wilcox wrote:
On Tue, Dec 26, 2017 at 07:54:40PM +0300, Kirill A. Shutemov wrote:
quoted
On Fri, Dec 15, 2017 at 02:03:35PM -0800, Matthew Wilcox wrote:
quoted
From: Matthew Wilcox <redacted>

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.
Looks great, thanks.

-- 
 Kirill A. Shutemov

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