|| ||Mel Gorman <firstname.lastname@example.org> |
|| ||Linux-MM <email@example.com> |
|| ||[PATCH 00/11] Swap-over-NFS without deadlocking V2 |
|| ||Mon, 6 Feb 2012 22:56:30 +0000|
|| ||Linux-Netdev <firstname.lastname@example.org>,
Andrew Morton <email@example.com>,
David Miller <firstname.lastname@example.org>,
Trond Myklebust <Trond.Myklebust@netapp.com>,
Neil Brown <email@example.com>,
Christoph Hellwig <firstname.lastname@example.org>,
Peter Zijlstra <email@example.com>,
Mel Gorman <firstname.lastname@example.org>|
|| ||Article, Thread
This patch series is based on top of "Swap-over-NBD without deadlocking v8"
as it depends on the same reservation of PF_MEMALLOC reserves logic.
When a user or administrator requires swap for their application, they
create a swap partition and file, format it with mkswap and activate it with
swapon. In diskless systems this is not an option so if swap if required
then swapping over the network is considered. The two likely scenarios
are when blade servers are used as part of a cluster where the form factor
or maintenance costs do not allow the use of disks and thin clients.
The Linux Terminal Server Project recommends the use of the Network
Block Device (NBD) for swap but this is not always an option. There is
no guarantee that the network attached storage (NAS) device is running
Linux or supports NBD. However, it is likely that it supports NFS so there
are users that want support for swapping over NFS despite any performance
concern. Some distributions currently carry patches that support swapping
over NFS but it would be preferable to support it in the mainline kernel.
Patch 1 avoids a stream-specific deadlock that potentially affects TCP.
Patch 2 is a small modification to SELinux to avoid using PFMEMALLOC
Patch 3 adds three helpers for filesystems to handle swap cache pages.
For example, page_file_mapping() returns page->mapping for
file-backed pages and the address_space of the underlying
swap file for swap cache pages.
Patch 4 adds two address_space_operations to allow a filesystem
to pin all metadata relevant to a swapfile in memory. Upon
successful activation, the swapfile is marked SWP_FILE and
the address space operation ->direct_IO is used for writing
and ->readpage for reading in swap pages.
Patch 5 notes that patch 3 is bolting
filesystem-specific-swapfile-support onto the side and that
the default handlers have different information to what
is available to the filesystem. This patch refactors the
code so that there are generic handlers for each of the new
Patch 6 adds an API to allow a vector of kernel addresses to be
translated to struct pages and pinned for IO.
Patch 7 updates NFS to use the helpers from patch 3 where necessary.
Patch 8 avoids setting PF_private on PG_swapcache pages within NFS.
Patch 9 implements the new swapfile-related address_space operations
for NFS and teaches the direct IO handler how to manage
Patch 10 prevents page allocator recursions in NFS by using GFP_NOIO
Patch 11 fixes a NULL pointer dereference that occurs when using
Documentation/filesystems/Locking | 13 ++++
Documentation/filesystems/vfs.txt | 12 +++
fs/nfs/Kconfig | 8 ++
fs/nfs/direct.c | 94 ++++++++++++++++--------
fs/nfs/file.c | 28 ++++++--
fs/nfs/inode.c | 6 ++
fs/nfs/internal.h | 7 +-
fs/nfs/pagelist.c | 8 +-
fs/nfs/read.c | 6 +-
fs/nfs/write.c | 93 ++++++++++++++----------
include/linux/blk_types.h | 2 +
include/linux/fs.h | 9 +++
include/linux/mm.h | 29 ++++++++
include/linux/nfs_fs.h | 4 +-
include/linux/pagemap.h | 5 ++
include/linux/sunrpc/xprt.h | 3 +
include/linux/swap.h | 8 ++
include/net/sock.h | 7 +-
mm/memory.c | 53 ++++++++++++++
mm/page_io.c | 144 +++++++++++++++++++++++++++++++++++++
mm/swap_state.c | 2 +-
mm/swapfile.c | 142 ++++++++++++++----------------------
net/caif/caif_socket.c | 2 +-
net/core/sock.c | 2 +-
net/ipv4/tcp_input.c | 12 ++--
net/sctp/ulpevent.c | 2 +-
net/sunrpc/Kconfig | 5 ++
net/sunrpc/clnt.c | 2 +
net/sunrpc/sched.c | 7 ++-
net/sunrpc/xprtsock.c | 53 ++++++++++++++
security/selinux/avc.c | 2 +-
31 files changed, 580 insertions(+), 190 deletions(-)
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