Minchan Kim
86d820b7ea
BACKPORT: zram: support idle/huge page writeback ...
Add a new feature "zram idle/huge page writeback". In the zram-swap use
case, zram usually has many idle/huge swap pages. It's pointless to keep
them in memory (ie, zram).
To solve this problem, this feature introduces idle/huge page writeback to
the backing device so the goal is to save more memory space on embedded
systems.
Normal sequence to use idle/huge page writeback feature is as follows,
while (1) {
# mark allocated zram slot to idle
echo all > /sys/block/zram0/idle
# leave system working for several hours
# Unless there is no access for some blocks on zram,
# they are still IDLE marked pages.
echo "idle" > /sys/block/zram0/writeback
or/and
echo "huge" > /sys/block/zram0/writeback
# write the IDLE or/and huge marked slot into backing device
# and free the memory.
}
Per the discussion at
https://lore.kernel.org/lkml/20181122065926.GG3441@jagdpanzerIV/T/#u ,
This patch removes direct incommpressibe page writeback feature
(d2afd25114f4 ("zram: write incompressible pages to backing device")).
Below concerns from Sergey:
== &< ==
"IDLE writeback" is superior to "incompressible writeback".
"incompressible writeback" is completely unpredictable and uncontrollable;
it depens on data patterns and compression algorithms. While "IDLE
writeback" is predictable.
I even suspect, that, *ideally*, we can remove "incompressible writeback".
"IDLE pages" is a super set which also includes "incompressible" pages.
So, technically, we still can do "incompressible writeback" from "IDLE
writeback" path; but a much more reasonable one, based on a page idling
period.
I understand that you want to keep "direct incompressible writeback"
around. ZRAM is especially popular on devices which do suffer from flash
wearout, so I can see "incompressible writeback" path becoming a dead
code, long term.
== &< ==
Below concerns from Minchan:
== &< ==
My concern is if we enable CONFIG_ZRAM_WRITEBACK in this implementation,
both hugepage/idlepage writeck will turn on. However someuser want to
enable only idlepage writeback so we need to introduce turn on/off knob
for hugepage or new CONFIG_ZRAM_IDLEPAGE_WRITEBACK for those usecase. I
don't want to make it complicated *if possible*.
Long term, I imagine we need to make VM aware of new swap hierarchy a
little bit different with as-is. For example, first high priority swap
can return -EIO or -ENOCOMP, swap try to fallback to next lower priority
swap device. With that, hugepage writeback will work tranparently.
So we could regard it as regression because incompressible pages doesn't
go to backing storage automatically. Instead, user should do it via "echo
huge" > /sys/block/zram/writeback" manually.
== &< ==
Link: http://lkml.kernel.org/r/20181127055429.251614-6-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Joey Pabalinas <joeypabalinas@gmail.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit a939888ec38bf1f33e4a903056677e92a4844244)
Conflicts:
drivers/block/zram/zram_drv.c
Fix usage of bio_init()
Bug: 117683045
Change-Id: I82afe541fdb60b24cde74f42de4d6b3dd6d8266c
Signed-off-by: Srinivas Paladugu <srnvs@google.com>
2019-02-01 09:26:15 +00:00
docs-rst: sphinxify 802.11 documentation
2016-10-11 16:19:17 -06:00
BACKPORT: zram: support idle/huge page writeback
2019-02-01 09:26:15 +00:00
tools: move accounting tool from Documentation
2016-09-23 13:07:15 -06:00
Merge branches 'acpi-button', 'acpi-battery' and 'acpi-doc'
2016-10-02 01:40:20 +02:00
linux-kselftest-4.9-rc1-update
2016-10-14 15:17:12 -07:00
arm64: Add work around for Arm Cortex-A55 Erratum 1024718
2018-05-16 10:08:42 +02:00
samples: move auxdisplay example code from Documentation
2016-09-23 11:52:32 -06:00
samples: move blackfin gptimers-example from Documentation
2016-10-10 07:12:02 -06:00
ANDROID: mmc: Add CONFIG_MMC_SIMULATE_MAX_SPEED
2017-01-27 13:54:59 -08:00
BACKPORT: zram: support idle/huge page writeback
2019-02-01 09:26:15 +00:00
Three fixes for the docs build, including removing an annoying warning on
2016-08-07 10:23:17 -04:00
samples: connector: from Documentation to samples directory
2016-04-28 07:47:35 -06:00
FROMLIST: cpufreq: Add android's 'interactive' governor
2017-01-31 10:47:32 -08:00
crypto: doc - Fix typo
2016-05-31 16:41:55 +08:00
mm: kmemleak: avoid using __va() on addresses that don't have a lowmem mapping
2016-10-11 15:06:33 -07:00
docs-rst: add inter-document cross references
2016-09-21 15:43:09 -06:00
BACKPORT: dm crypt: optionally support larger encryption sector size
2018-12-13 09:34:59 -08:00
This is the 4.9.134 stable release
2018-10-18 19:18:13 +02:00
dmaengine: documentation to the new callback mechanism
2016-08-08 08:11:42 +05:30
A single commit converting the mac80211 DocBook template over to Sphinx.
2016-10-14 14:11:22 -07:00
docs: Don't format internal MPT docs
2016-09-06 09:15:48 -06:00
power supply and reset changes for the v4.9 series
2016-10-06 18:21:15 -07:00
Documentation: fb: fix spelling mistakes
2016-05-10 12:05:27 +03:00
Documentation: MIPS supports HAVE_REGS_AND_STACK_ACCESS_API
2016-10-13 17:19:19 +02:00
This is the 4.9.153 stable release
2019-01-26 12:03:01 +01:00
Documentation: fix common spelling mistakes
2016-04-28 07:51:59 -06:00
gpio/board.txt: point to gpiod_set_value
2016-10-20 14:14:11 +02:00
UPSTREAM: drm/fences: add DOC: for explicit fencing
2017-05-23 15:47:18 -07:00
Documentation: HID: Intel ISH HID document
2016-08-17 11:13:07 +02:00
hwmon: (ina2xx) fix sysfs shunt resistor read access
2018-10-03 17:01:52 -07:00
i2c: Documentation: i2c-topology: fix minor whitespace nit
2016-11-10 21:18:56 +01:00
selftests: move ia64 tests from Documentation/ia64
2016-09-20 09:58:12 -06:00
iio: Documentation: Correct the path used to create triggers.
2016-10-01 00:49:58 -06:00
IB/hfi1: Document new sysfs entries for hfi1 driver
2016-10-02 08:42:19 -04:00
UPSTREAM: HID: sony: Report DS4 motion sensors through a separate device
2018-10-24 17:03:59 -07:00
BACKPORT: tee: generic TEE subsystem
2017-12-05 14:00:37 +00:00
Documentatio: HOWTO: remove regression postings info from translations
2016-04-16 10:49:08 -06:00
Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild
2016-10-14 14:26:58 -07:00
Documentation: kdump: Add description of enable multi-cpus support
2016-09-20 18:02:54 -06:00
locking/Documentation: Add Korean translation
2016-08-12 08:24:14 +02:00
tools: move laptops dslm tool from Documentation
2016-09-23 13:07:21 -06:00
Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds
2016-10-04 10:25:53 -07:00
Documentation: livepatch: add section about arch-specific code
2016-08-18 23:41:56 +02:00
locking/lglock: Remove lglock implementation
2016-09-22 15:25:56 +02:00
videodev2.h: go back to limited range Y'CbCr for SRGB and, ADOBERGB
2017-02-23 17:44:37 +01:00
samples: move mic/mpssd example code from Documentation
2016-09-20 12:38:48 -06:00
samples: move misc-devices/mei example code from Documentation
2016-09-23 11:51:43 -06:00
mmc: core: Extend sysfs with DSR register
2016-07-25 10:34:51 +02:00
This is the 4.9.134 stable release
2018-10-18 19:18:13 +02:00
libnvdimm, btt: update the usage section in Documentation
2016-06-17 16:23:23 -07:00
PCI changes for the v4.9 merge window:
2016-10-07 11:46:37 -07:00
tools: move pcmcia crc32hash tool from Documentation
2016-09-23 13:07:27 -06:00
perf: xgene: Add APM X-Gene SoC Performance Monitoring Unit driver
2016-09-15 11:20:55 -07:00
power supply and reset changes for the v4.9 series
2016-10-06 18:21:15 -07:00
powerpc updates for 4.9
2016-10-07 20:19:31 -07:00
Documentation: pps: fix spelling mistake
2016-04-28 07:23:59 -06:00
selftests: move prctl tests from Documentation/prctl
2016-09-20 09:09:09 -06:00
selftests: move ptp tests from Documentation/ptp
2016-09-20 09:54:38 -06:00
rapidio/documentation/mport_cdev: add missing parameter description
2016-09-01 17:52:02 -07:00
kthread: kthread worker API cleanup
2016-10-11 15:06:33 -07:00
s390/Documentation: improve sort command for trace buffer
2016-06-13 15:58:23 +02:00
ANDROID: sched/tune: add detailed documentation
2017-01-31 10:46:34 -08:00
scsi: g_NCR5380: Stop using scsi_module.c
2016-09-29 21:52:43 -04:00
f2fs: catch up to v4.14-rc1
2017-10-13 11:27:08 +00:00
Documentation: rs485: Do not define manually the ioctl
2016-08-18 11:08:33 -06:00
ASoC: Updates for v4.8
2016-07-26 10:35:31 +02:00
docs: sphinx-extensions: make rstFlatTable work with docutils 0.13
2017-01-09 08:32:18 +01:00
This is the documentation update pull for the 4.9 merge window.
2016-10-04 13:54:07 -07:00
Doc: update 00-INDEX files to reflect the runnable code move
2016-10-10 07:12:09 -06:00
This is the 4.9.142 stable release
2018-12-01 10:00:35 +01:00
target: make close_session optional
2016-05-10 01:19:26 -07:00
thermal: Add support for hardware-tracked trip points
2016-09-27 14:02:16 +08:00
Doc: update 00-INDEX files to reflect the runnable code move
2016-10-10 07:12:09 -06:00
tpm: Add documentation for the tpm_vtpm_proxy device driver
2016-06-25 17:26:35 +03:00
UPSTREAM: trace: Update documentation for mono, mono_raw and boot clock
2017-01-27 13:55:48 -08:00
Documentation: tiny typo fix in usb/gadget_multi.txt
2016-06-23 08:09:10 -06:00
KVM: x86: Add a framework for supporting MSR-based features
2018-08-15 18:14:52 +02:00
Three fixes for the docs build, including removing an annoying warning on
2016-08-07 10:23:17 -04:00
w1: add ability to set (SRAM) and store (EEPROM) configuration for temp sensors like DS18B20
2016-05-01 14:37:49 -07:00
linux-kselftest-4.9-rc1-update
2016-10-14 15:17:12 -07:00
x86/pti: Document fix wrong index
2018-01-23 19:57:10 +01:00
xtensa: cleanup MMU setup and kernel layout macros
2016-07-24 06:33:58 +03:00
docs: deprecate kernel-doc-nano-HOWTO.txt
2016-07-20 16:45:37 -06:00
Add .pyc files to .gitignore
2016-06-30 13:07:33 -06:00
BACKPORT: Documentation: tee subsystem and op-tee driver
2017-12-05 14:00:47 +00:00
documentation: trivial typo: adding-syscalls.txt: s/statat/fstatat/
2016-04-18 11:31:49 -06:00
ANDROID: pstore: Update Documentation/android.txt
2017-01-27 13:52:20 -08:00
docs: Clean up bare :: lines
2016-09-20 18:46:36 -06:00
bcache: documentation formatting, edited for clarity, stripe alignment notes
2016-06-23 07:58:38 -06:00
binfmt_misc: add F option description to documentation
2016-03-30 14:12:22 -07:00
kbuild: verify that $DEPMOD is installed
2018-08-17 20:59:29 +02:00
Documentation: clk: update file names containing referenced structures
2016-08-14 12:12:36 -06:00
URL changed for Linux Foundation TAB
2016-10-01 00:57:13 -06:00
docs: Remove space-before-label guidance from CodingStyle
2016-09-21 15:53:31 -06:00
docs-rst: fix LaTeX \DURole renewcommand with Sphinx 1.3+
2017-01-12 11:39:32 +01:00
topology/sysfs: provide drawer id and siblings attributes
2016-06-13 15:58:27 +02:00
Documentation: update the devices.txt documentation
2016-03-29 10:11:44 -07:00
Documentation: DMA-API-HOWTO: Fix a typo
2016-09-20 17:58:46 -06:00
dma-mapping: add dma_{map,unmap}_resource
2016-09-26 22:16:41 +05:30
dma-mapping: introduce the DMA_ATTR_NO_WARN attribute
2016-10-11 15:06:32 -07:00
doc-rst: add docutils config file
2016-08-14 11:52:40 -06:00
GCC plugin infrastructure
2016-06-07 22:57:10 +02:00
Documentation/email-clients.txt: convert it to ReST markup
2016-09-21 15:41:50 -06:00
GCC plugin infrastructure
2016-06-07 22:57:10 +02:00
docs: Clean up bare :: lines
2016-09-20 18:46:36 -06:00
Documentation: Add section about CPU vulnerabilities
2018-08-15 18:14:51 +02:00
Documentation/IRQ-domain.txt: Document irq_domain_create_{linear, tree}
2016-03-31 00:32:59 -06:00
Documentation: Add ISA bus driver documentation
2016-05-02 09:32:04 -07:00
docs: deprecate kernel-doc-nano-HOWTO.txt
2016-07-20 16:45:37 -06:00
Documentation/kernel-docs.txt: reorder based on timestamp
2016-09-20 18:54:42 -06:00
This is the documentation update pull for the 4.9 merge window.
2016-10-04 13:54:07 -07:00
This is the 4.9.136 stable release
2018-11-23 10:47:24 +01:00
Documenation: update cgroup's document path
2016-08-03 15:43:58 -06:00
Documentation: kprobes: Document jprobes stack copying limitations
2016-08-15 10:19:11 -06:00
kselftest: kselftest documentation improvement
2016-09-20 08:58:27 -06:00
KVM: VMX: Tell the nested hypervisor to skip L1D flush on vmentry
2018-08-15 18:14:53 +02:00
Documentation: lzo: fix spelling mistakes
2016-04-28 07:23:11 -06:00
samples: move blackfin gptimers-example from Documentation
2016-10-10 07:12:02 -06:00
doc-rst: generic way to build PDF of sub-folders
2016-09-01 08:49:23 -06:00
Documentation/HOWTO: add cross-references to other documents
2016-09-20 18:41:04 -06:00
md-cluster: change array_sectors and update size are not supported
2016-05-04 12:39:35 -07:00
Documentation: fix wrong value in md.txt
2016-06-23 08:08:36 -06:00
locking/Documentation: Fix a typo of example result
2016-08-12 08:24:13 +02:00
memory_hotplug: introduce CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
2016-05-19 19:12:14 -07:00
Documentation/module-signing.txt: Note need for version info if reusing a key
2016-07-27 12:38:00 +09:30
phy: core: Allow children node to be overridden
2016-04-29 16:39:39 +02:00
pinctrl: Flag strict is a field in struct pinmux_ops
2016-06-23 10:50:10 +02:00
lib/vsprintf: Remove atomic-unsafe support for %pCr
2018-07-03 11:23:06 +02:00
pwm: Update documentation
2016-05-17 14:48:04 +02:00
ramoops: use DT reserved-memory bindings
2016-08-05 11:21:36 -07:00
remoteproc: Split driver and consumer dereferencing
2016-10-02 22:50:21 -07:00
Documentation: robust-futexes: fix spelling mistakes
2016-04-28 07:26:41 -06:00
rpmsg: use module_rpmsg_driver in existing drivers and examples
2016-05-06 11:09:01 -07:00
Documentation/HOWTO: add cross-references to other documents
2016-09-20 18:41:04 -06:00
Documentation/spec_ctrl: Do some minor cleanups
2018-05-22 16:58:02 +02:00
Documentation: Document array_index_nospec
2018-02-13 12:35:59 +01:00
Documentation/HOWTO: add cross-references to other documents
2016-09-20 18:41:04 -06:00
Documentation: stable-kernel-rules: fix stable-tag format
2017-04-12 12:41:15 +02:00
jump_labels: Allow array initialisers
2016-09-07 09:41:11 +01:00
docs-rst: add inter-document cross references
2016-09-21 15:43:09 -06:00
docs-rst: add inter-document cross references
2016-09-21 15:43:09 -06:00
docs-rst: add inter-document cross references
2016-09-21 15:43:09 -06:00
ANDROID: sync: add Documentation/sync.txt
2017-01-27 13:51:38 -08:00
Documentation: add doc for sync_file_get_fence()
2016-08-11 15:33:24 +05:30
Doc: correct the location of sysrq.c
2016-04-28 08:02:36 -06:00
BACKPORT: tee.txt: standardize document format
2018-01-12 16:44:40 +00:00
vme: Update documentation to match api
2016-08-31 13:20:16 +02:00
workqueue: Fix a typo in workqueue.txt
2016-07-06 02:37:38 -06:00
Documentation: xillybus: fix spelling mistake
2016-04-28 07:44:54 -06:00
86d820b7ea
