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Mel Gorman 62c230bc17 mm: add support for a filesystem to activate swap files and use direct_IO for writing swap pages 
Currently swapfiles are managed entirely by the core VM by using ->bmap to
allocate space and write to the blocks directly.  This effectively ensures
that the underlying blocks are allocated and avoids the need for the swap
subsystem to locate what physical blocks store offsets within a file.

If the swap subsystem is to use the filesystem information to locate the
blocks, it is critical that information such as block groups, block
bitmaps and the block descriptor table that map the swap file were
resident in memory.  This patch adds address_space_operations that the VM
can call when activating or deactivating swap backed by a file.

  int swap_activate(struct file *);
  int swap_deactivate(struct file *);

The ->swap_activate() method is used to communicate to the file that the
VM relies on it, and the address_space should take adequate measures such
as reserving space in the underlying device, reserving memory for mempools
and pinning information such as the block descriptor table in memory.  The
->swap_deactivate() method is called on sys_swapoff() if ->swap_activate()
returned success.

After a successful swapfile ->swap_activate, the swapfile is marked
SWP_FILE and swapper_space.a_ops will proxy to
sis->swap_file->f_mappings->a_ops using ->direct_io to write swapcache
pages and ->readpage to read.

It is perfectly possible that direct_IO be used to read the swap pages but
it is an unnecessary complication.  Similarly, it is possible that
->writepage be used instead of direct_io to write the pages but filesystem
developers have stated that calling writepage from the VM is undesirable
for a variety of reasons and using direct_IO opens up the possibility of
writing back batches of swap pages in the future.

[a.p.zijlstra@chello.nl: Original patch]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Neil Brown <neilb@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-31 18:42:47 -07:00
..
ABI mm: prepare for removal of obsolete /proc/sys/vm/nr_pdflush_threads 2012-07-31 18:42:40 -07:00
accounting
acpi Update documentation for parameter *notrigger* in einj.txt 2012-03-30 03:30:19 -04:00
aoe Documentation: remove references to /etc/modprobe.conf 2012-03-30 16:03:15 -07:00
arm Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2012-07-24 13:34:56 -07:00
auxdisplay
backlight backlight: new backlight driver for LP855x devices 2012-03-23 16:58:33 -07:00
blackfin Documentation: Fix typo in multiple files in Documentation 2012-04-16 14:37:13 +02:00
block Documentation: drop as block elevator reference in switching-sched.txt 2011-11-04 12:01:48 -07:00
blockdev Documentation: remove references to /etc/modprobe.conf 2012-03-30 16:03:15 -07:00
cdrom doc: fix broken references 2011-09-27 18:08:04 +02:00
cgroups mm/memcg: complete documentation for tcp memcg files 2012-07-31 18:42:43 -07:00
connector connector: Move cn_test.c away from NLMSG_PUT(). 2012-06-26 21:19:02 -07:00
console
cpu-freq Doc: cpufreq: Fix typo and outdated line 2011-11-08 10:23:29 +01:00
cpuidle cpuidle: add a sysfs entry to disable specific C state for debug purpose. 2012-03-30 01:52:58 -04:00
cris CRIS: Update documentation 2012-04-03 13:09:18 +02:00
crypto
development-process Documentation: Update stable address 2011-12-12 14:14:31 -08:00
device-mapper dm thin: add read only and fail io modes 2012-07-27 15:08:16 +01:00
devicetree MFD bits for the 3.6 merge window. 2012-07-30 12:41:17 -07:00
DocBook Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media 2012-07-30 19:03:41 -07:00
driver-model Pin control subsystem changes for kernel 3.5: 2012-05-21 16:58:23 -07:00
dvb Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media 2012-07-30 19:03:41 -07:00
early-userspace
EDID drm: allow loading an EDID as firmware to override broken monitor 2012-03-20 10:09:28 +00:00
extcon Documentation/extcon: porting guide for Android kernel switch driver. 2012-04-20 09:24:27 -07:00
fault-injection fault-injection: add tool to run command with failslab or fail_page_alloc 2012-07-30 17:25:22 -07:00
fb Documentation: remove references to /etc/modprobe.conf 2012-03-30 16:03:15 -07:00
filesystems mm: add support for a filesystem to activate swap files and use direct_IO for writing swap pages 2012-07-31 18:42:47 -07:00
firmware_class
frv doc: fix broken references 2011-09-27 18:08:04 +02:00
hid HID: uhid: add documentation 2012-06-18 13:42:03 +02:00
hwmon hwmon: Honeywell Humidicon HIH-6130/HIH-6131 humidity and temperature sensor driver 2012-07-21 21:48:44 -07:00
i2c i2c-i801: Enable IRQ for SMBus transactions 2012-07-24 14:13:58 +02:00
i2o Documentation: Fix multiple typo in Documentation 2012-03-07 16:08:24 +01:00
ia64
ide Documentation: remove references to /etc/modprobe.conf 2012-03-30 16:03:15 -07:00
infiniband
input Input: add driver for FT5x06 based EDT displays 2012-07-24 23:55:03 -07:00
ioctl mei: update Documentation/ioctl/ioctl-number.txt 2012-05-09 14:00:31 -07:00
isdn Documentation: remove references to /etc/modprobe.conf 2012-03-30 16:03:15 -07:00
ja_JP
kbuild Merge branch 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2012-05-28 10:37:56 -07:00
kdump kexec: update URL of kexec homepage 2012-07-18 18:35:57 -07:00
ko_KR driver-core: documentation: fix up Greg's email address 2012-02-15 14:48:01 -08:00
laptops Documentation: asus-laptop.txt references an obsolete Kconfig item 2012-06-28 12:04:16 +02:00
leds LEDS: add BlinkM RGB LED driver, documentation and update MAINTAINERS 2012-07-24 16:00:51 +08:00
m68k
make
memory-devices memory: emif: add basic infrastructure for EMIF driver 2012-05-02 00:10:49 -07:00
mips
misc-devices mei: mei.txt: minor grammar fixes 2012-06-13 13:38:25 -07:00
mmc mmc: core: Fixup delayed work clock gating patch 2012-01-11 23:58:43 -05:00
mn10300
mtd
namespaces
netlabel
networking net-next: minor cleanups for bonding documentation 2012-07-22 12:44:01 -07:00
nfc NFC: Error management documentation 2012-07-09 16:42:11 -04:00
parisc Documentation: Fix typo in multiple files in Documentation 2012-04-16 14:37:13 +02:00
PCI doc: fix broken references 2011-09-27 18:08:04 +02:00
pcmcia
power Merge branch 'pm-doc' 2012-07-19 00:03:46 +02:00
powerpc Revert "powerpc/hw-breakpoint: Use generic hw-breakpoint interfaces for new PPC ptrace flags" 2012-05-22 14:37:24 +10:00
pps
prctl security: Minor improvements to no_new_privs documentation 2012-07-08 00:25:48 +10:00
pti
ptp
rapidio RapidIO: documentation update 2011-11-02 16:07:02 -07:00
RCU rcu: Update documentation to cover call_srcu() and srcu_barrier(). 2012-07-02 12:34:03 -07:00
s390 Documentation: remove references to /etc/modprobe.conf 2012-03-30 16:03:15 -07:00
scheduler sched: Remove stale power aware scheduling remnants and dysfunctional knobs 2012-05-17 13:48:56 +02:00
scsi Merge branch 'delete-mca' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux 2012-05-23 17:12:06 -07:00
security Smack: allow for significantly longer Smack labels v4 2012-05-14 22:48:38 -07:00
serial serial: delete the MCA specific 8250 support. 2012-05-17 19:02:14 -04:00
sh
sound Sound update for 3.6-rc1 2012-07-24 13:37:37 -07:00
spi spi: create a message queueing infrastructure 2012-03-07 19:19:48 -07:00
sysctl mm, oom: replace some information in tasklist dump 2012-07-31 18:42:42 -07:00
target Documentation: Fix typo in tcm_mod_builder.py 2012-02-10 09:52:18 +01:00
telephony
thermal Thermal: Documentation update 2012-07-24 23:20:40 -04:00
timers doc: fix broken references 2011-09-27 18:08:04 +02:00
trace tracing: Fix kconfig warning due to a typo 2012-05-08 14:17:25 +02:00
usb usb: gadget: mass_storage: add documentation 2012-06-15 14:32:30 +03:00
vDSO
video4linux Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media 2012-07-30 19:03:41 -07:00
virtual KVM updates for the 3.6 merge window 2012-07-24 12:01:20 -07:00
vm mm/frontswap: cleanup doc and comment error 2012-07-23 11:16:20 -04:00
w1 w1: Add 1-wire slave device driver for DS28E04-100 2012-06-13 16:47:10 -07:00
watchdog Watchdog: DA9052/53 PMIC watchdog support 2012-05-30 07:56:12 +02:00
wimax
x86 Merge branch 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-07-26 13:13:25 -07:00
zh_CN Fix a mistake sentence in the file 'Documentation/zh_CN/magic-number.txt' 2012-05-07 17:20:27 -07:00
.gitignore
00-INDEX MCA: delete all remaining traces of microchannel bus support. 2012-05-17 19:06:13 -04:00
applying-patches.txt
atomic_ops.txt doc: Add load/store guarantees to Documentation/atomic-ops.txt 2011-12-11 10:31:58 -08:00
bad_memory.txt
basic_profiling.txt
binfmt_misc.txt
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
BUG-HUNTING
bus-virt-phys-mapping.txt doc: fix broken references 2011-09-27 18:08:04 +02:00
cachetlb.txt
Changes
circular-buffers.txt
clk.txt Documentation: common clk API 2012-03-16 20:35:01 +00:00
coccinelle.txt coccinelle.txt: update documentation to include M= option 2012-01-14 22:25:56 +01:00
CodingStyle CodingStyle: add kmalloc_array() to memory allocators 2012-05-31 17:49:26 -07:00
cpu-hotplug.txt documentation: remove references to cpu_*_map. 2012-03-29 15:38:31 +10:30
cpu-load.txt
cputopology.txt
crc32.txt crc32: move long comment about crc32 fundamentals to Documentation/ 2012-03-23 16:58:37 -07:00
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
devices.txt Doc: document max raw dev number 2012-06-03 12:05:50 +02:00
digsig.txt crypto: digital signature verification support 2011-11-09 12:10:37 +02:00
DMA-API-HOWTO.txt
DMA-API.txt include/linux/dma-mapping.h: add dma_zalloc_coherent() 2011-11-02 16:07:02 -07:00
DMA-attributes.txt common: DMA-mapping: add DMA_ATTR_SKIP_CPU_SYNC attribute 2012-07-30 12:25:47 +02:00
dma-buf-sharing.txt dma-buf: add initial vmap documentation 2012-05-25 12:51:11 +05:30
DMA-ISA-LPC.txt
dmaengine.txt Documentation: Fix multiple typo in Documentation 2012-03-07 16:08:24 +01:00
dontdiff kconfig: remove lkc_defs.h from .gitignore and dontdiff 2012-07-13 15:08:25 +02:00
dynamic-debug-howto.txt dynamic_debug: update Documentation/*, Kconfig.debug 2012-04-30 16:26:30 -04:00
edac.txt Merge branch 'devel' 2012-07-29 21:11:05 -03:00
eisa.txt MCA: delete all remaining traces of microchannel bus support. 2012-05-17 19:06:13 -04:00
email-clients.txt
feature-removal-schedule.txt mm: prepare for removal of obsolete /proc/sys/vm/nr_pdflush_threads 2012-07-31 18:42:40 -07:00
flexible-arrays.txt
futex-requeue-pi.txt
gcov.txt
gpio.txt gpio: add flags to export GPIOs when requesting 2012-04-05 21:24:06 -07:00
highuid.txt
HOWTO docs: update HOWTO for 2.6.x -> 3.x versioning 2012-04-19 19:13:08 -07:00
hw_random.txt
hwspinlock.txt hwspinlock/core: register a bank of hwspinlocks in a single API call 2011-09-21 19:45:34 +03:00
init.txt
initrd.txt Documentation/initrd.txt: Change the location of util-linux 2012-05-25 16:18:34 +02:00
Intel-IOMMU.txt
intel_txt.txt
io-mapping.txt
io_ordering.txt
iostats.txt
IPMI.txt
IRQ-affinity.txt
IRQ-domain.txt irq_domain: add documentation and MAINTAINERS entry. 2012-02-14 14:06:47 -07:00
IRQ.txt
irqflags-tracing.txt
isapnp.txt
java.txt
kernel-doc-nano-HOWTO.txt
kernel-docs.txt doc: fix broken references 2011-09-27 18:08:04 +02:00
kernel-parameters.txt Merge branch 'for-linus-for-3.6-rc1' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping 2012-07-30 10:11:31 -07:00
kmemcheck.txt
kmemleak.txt kmemleak: Handle percpu memory allocation 2011-12-02 16:12:42 +00:00
kobject.txt driver-core: documentation: fix up Greg's email address 2012-02-15 14:48:01 -08:00
kprobes.txt
kref.txt
ldm.txt
local_ops.txt
lockdep-design.txt lockdep: Update documentation for lock-class leak detection 2011-12-11 10:31:23 -08:00
lockstat.txt
lockup-watchdogs.txt watchdog: Update documentation 2012-02-11 15:11:28 +01:00
logo.gif
logo.txt
magic-number.txt drivers/net: fix up stale paths from driver reorg 2012-01-30 12:54:40 -05:00
Makefile mei: move doc files Documentation/misc-devices/mei 2012-05-09 13:59:09 -07:00
ManagementStyle Documentation: ManagementStyle: fixed typo 2012-06-28 12:03:15 +02:00
md.txt md: create externally visible flags for supporting hot-replace. 2011-12-23 10:17:51 +11:00
media-framework.txt [media] media: Add link_validate() op to check links to the sink pad 2012-05-14 08:44:11 -03:00
memory-barriers.txt doc: fix broken references 2011-09-27 18:08:04 +02:00
memory-hotplug.txt Documentation: Fix typo in multiple files in Documentation 2012-04-16 14:37:13 +02:00
memory.txt
mono.txt Documentation: remove references to /etc/modprobe.conf 2012-03-30 16:03:15 -07:00
mutex-design.txt
nommu-mmap.txt
numastat.txt Doc: Update numastat.txt 2012-02-28 16:05:06 +01:00
oops-tracing.txt module,bug: Add TAINT_OOT_MODULE flag for modules not built in-tree 2011-11-07 07:54:42 +10:30
padata.txt
parport-lowlevel.txt
parport.txt Documentation: remove references to /etc/modprobe.conf 2012-03-30 16:03:15 -07:00
pi-futex.txt
pinctrl.txt pinctrl: implement devm_pinctrl_get()/put() 2012-04-18 13:53:13 +02:00
pnp.txt
preempt-locking.txt
printk-formats.txt vsprintf: add support of '%*ph[CDN]' 2012-07-30 17:25:14 -07:00
prio_tree.txt
pwm.txt pwm: Add table-based lookup for static mappings 2012-06-15 12:56:53 +02:00
ramoops.txt pstore/ram: Add ftrace messages handling 2012-07-17 10:14:17 -07:00
rbtree.txt
remoteproc.txt remoteproc: adopt the driver core's alloc/add/del/put naming 2012-07-06 00:53:27 +03:00
rfkill.txt doc: fix broken references 2011-09-27 18:08:04 +02:00
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt rpmsg: add virtio-based remote processor messaging bus 2012-02-08 22:53:58 +02:00
rt-mutex-design.txt
rt-mutex.txt
rtc.txt
SAK.txt
SecurityBugs
serial-console.txt
sgi-ioc4.txt
sgi-visws.txt
SM501.txt
sparse.txt
spinlocks.txt
stable_api_nonsense.txt
stable_kernel_rules.txt stable: Allow merging of backports for serious user-visible performance issues 2012-06-25 12:11:58 -07:00
static-keys.txt Documentation: Fix typo in multiple files in Documentation 2012-04-16 14:37:13 +02:00
SubmitChecklist
SubmittingDrivers
SubmittingPatches Documentation/SubmittingPatches: suggested the use of scripts/get_maintainer.pl 2012-05-25 16:18:30 +02:00
svga.txt
sysfs-rules.txt
sysrq.txt Documentation: sysrq: Crutcher Dunnavant is unavailable 2012-03-30 16:03:15 -07:00
unaligned-memory-access.txt
unicode.txt
unshare.txt
VGA-softcursor.txt
vgaarbiter.txt misc latin1 to utf8 conversions 2012-01-02 13:04:55 +01:00
video-output.txt
vme_api.txt VME: Move API documentation to Documentation folder 2012-05-08 16:01:34 -07:00
volatile-considered-harmful.txt
workqueue.txt workqueue: reimplement WQ_HIGHPRI using a separate worker_pool 2012-07-13 22:24:45 -07:00
xz.txt
zorro.txt