[PATCH 0/3] RFC improvements to radix-tree related to DAX

From: NeilBrown <neilb@suse.com>
To: Ross Zwisler <ross.zwisler@linux.intel.com>,
	Matthew Wilcox <matthew.r.wilcox@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Jan Kara <jack@suse.cz>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org
Subject: [PATCH 0/3] RFC improvements to radix-tree related to DAX
Date: Sun, 28 Feb 2016 16:09:29 +1100	[thread overview]
Message-ID: <145663588892.3865.9987439671424028216.stgit@notabene> (raw)

Hi,

While pondering some issues with DAX and how it uses the radix tree I
conceived the following patches.  I don't know if they'll be useful
but I thought I would post them in case they are helpful.

The first is quite independent of the others - it removes some DAX
specific #defines from radix-tree.h which is a generic ADT.

The second makes an extra bit available when exception data is
stored in the radix tree.

The third uses this bit to provide a sleeping lock.  With this
it should be possible to delete exceptional entries from the radix
tree in a race-free way without external locking.
Like the page lock it requires an external set of wait_queue_heads.
The same ones used for page_lock would be suitable.

Note that this code is only compile tested.

NeilBrown

---

NeilBrown (3):
      DAX: move RADIX_DAX_ definitions to dax.c
      radix-tree: make 'indirect' bit available to exception entries.
      radix-tree: support locking of individual exception entries.

 fs/dax.c                   |    9 ++
 include/linux/radix-tree.h |   28 +++++---
 lib/radix-tree.c           |  160 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 185 insertions(+), 12 deletions(-)

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