This patch series is based on top of "Swap-over-NBD without deadlocking v6" 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 reserves. Patch 3 adds four address_space_operations to allow a filesystem to optionally control a swapfile. The news handlers are expected to map requests to the swapspace operations to the underlying file mapping. Patch 4 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 address_space operations. Patch 5 adds some helpers for filesystems to handle swap cache pages. Patch 6 updates NFS to use the helpers from patch 5 where necessary. Patch 7 avoids setting PF_private on PG_swapcache pages within NFS. Patch 8 implements the new swapfile-related address_space operations for NFS. Patch 9 prevents page allocator recursions in NFS by using GFP_NOIO where appropriate. Patch 10 fixes a NULL pointer dereference that occurs when using swap-over-NFS. Documentation/filesystems/Locking | 23 +++++ Documentation/filesystems/vfs.txt | 21 +++++ fs/nfs/Kconfig | 8 ++ fs/nfs/file.c | 26 +++++- fs/nfs/inode.c | 6 ++ fs/nfs/internal.h | 7 +- fs/nfs/pagelist.c | 8 +- fs/nfs/read.c | 6 +- fs/nfs/write.c | 163 +++++++++++++++++++++++++-------- include/linux/fs.h | 10 ++ include/linux/mm.h | 25 +++++ include/linux/nfs_fs.h | 2 + include/linux/pagemap.h | 5 + include/linux/sunrpc/xprt.h | 3 + include/linux/swap.h | 7 ++ include/net/sock.h | 7 +- mm/page_io.c | 181 ++++++++++++++++++++++++++++++++----- mm/swap_state.c | 2 +- mm/swapfile.c | 138 ++++++++++------------------ 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 | 57 ++++++++++++ security/selinux/avc.c | 2 +- 28 files changed, 561 insertions(+), 178 deletions(-) -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
