From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 26 Dec 2017 19:43:40 -0800 From: Matthew Wilcox To: "Kirill A. Shutemov" Cc: linux-kernel@vger.kernel.org, Matthew Wilcox , Ross Zwisler , David Howells , Shaohua Li , Jens Axboe , Rehas Sachdeva , Marc Zyngier , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-nilfs@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-xfs@vger.kernel.org, linux-usb@vger.kernel.org, linux-raid@vger.kernel.org Subject: Re: [PATCH v5 03/78] xarray: Add the xa_lock to the radix_tree_root Message-ID: <20171227034340.GC24828@bombadil.infradead.org> References: <20171215220450.7899-1-willy@infradead.org> <20171215220450.7899-4-willy@infradead.org> <20171226165440.tv6inwa2fgk3bfy6@node.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171226165440.tv6inwa2fgk3bfy6@node.shutemov.name> Sender: owner-linux-mm@kvack.org List-ID: 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 > > > > 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. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org