__module_put_and_exit() is makred noreturn in module.h declaration, but is
lacking the attribute in the definition, which makes some tools (such as
sparse) unhappy. Amend the definition with the attribute as well (and
reformat the declaration so that it uses more common format).
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Merge updates from Andrew Morton:
- a few misc bits
- ocfs2
- most(?) of MM
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (125 commits)
thp: fix comments of __pmd_trans_huge_lock()
cgroup: remove unnecessary 0 check from css_from_id()
cgroup: fix idr leak for the first cgroup root
mm: memcontrol: fix documentation for compound parameter
mm: memcontrol: remove BUG_ON in uncharge_list
mm: fix build warnings in <linux/compaction.h>
mm, thp: convert from optimistic swapin collapsing to conservative
mm, thp: fix comment inconsistency for swapin readahead functions
thp: update Documentation/{vm/transhuge,filesystems/proc}.txt
shmem: split huge pages beyond i_size under memory pressure
thp: introduce CONFIG_TRANSPARENT_HUGE_PAGECACHE
khugepaged: add support of collapse for tmpfs/shmem pages
shmem: make shmem_inode_info::lock irq-safe
khugepaged: move up_read(mmap_sem) out of khugepaged_alloc_page()
thp: extract khugepaged from mm/huge_memory.c
shmem, thp: respect MADV_{NO,}HUGEPAGE for file mappings
shmem: add huge pages support
shmem: get_unmapped_area align huge page
shmem: prepare huge= mount option and sysfs knob
mm, rmap: account shmem thp pages
...
Pull power supply and reset updates from Sebastian Reichel:
- introduce reboot mode driver
- add DT support to max8903
- add power supply support for axp221
- misc fixes
* tag 'for-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply:
power: reset: add reboot mode driver
dt-bindings: power: reset: add document for reboot-mode driver
power_supply: fix return value of get_property
power: qcom_smbb: Make an extcon for usb cable detection
max8903: adds support for initiation via device tree
max8903: adds documentation for device tree bindings.
max8903: remove unnecessary 'out of memory' error message.
max8903: removes non zero validity checks on gpios.
max8903: adds requesting of gpios.
max8903: cleans up confusing relationship between dc_valid, dok and dcm.
max8903: store pointer to pdata instead of copying it.
power_supply: bq27xxx_battery: Group register mappings into one table
docs: Move brcm,bcm21664-resetmgr.txt
power/reset: make syscon_poweroff() static
power: axp20x_usb: Add support for usb power-supply on axp22x pmics
power_supply: bq27xxx_battery: Index register numbers by enum
power_supply: bq27xxx_battery: Fix copy/paste error in header comment
MAINTAINERS: Add file patterns for power supply device tree bindings
power: reset: keystone: Enable COMPILE_TEST
Pull regulator updates from Mark Brown:
"A quiet regulator API release, a few new drivers and some fixes but
nothing too notable. There will also be some updates for the PWM
regulator coming through the PWM tree which provide much smoother
operation when taking over an already running PWM regulator after boot
using some new PWM APIs.
Summary:
- Support for configuration of the initial suspend state from DT.
- New drivers for Mediatek MT6323, Ricoh RN5T567 and X-Powers AXP809"
* tag 'regulator-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator: (38 commits)
regulator: da9053/52: Fix incorrectly stated minimum and maximum voltage limits
regulator: mt6323: Constify struct regulator_ops
regulator: mt6323: Fix module description
regulator: mt6323: Add support for MT6323 regulator
regulator: Add document for MT6323 regulator
regulator: da9210: addition of device tree support
regulator: act8865: Fix missing of_node_put() in act8865_pdata_from_dt()
regulator: qcom_smd: Avoid overlapping linear voltage ranges
regulator: s2mps11: Fix the voltage linear range for s2mps15
regulator: pwm: Fix regulator ramp delay for continuous mode
regulator: da9211: add descriptions for da9212/da9214
mfd: rn5t618: Register restart handler
mfd: rn5t618: Register power off callback optionally
regulator: rn5t618: Add RN5T567 PMIC support
mfd: rn5t618: Add Ricoh RN5T567 PMIC support
ARM: dts: meson: minix-neo-x8: define PMIC as power controller
regulator: tps65218: force set power-up/down strobe to 3 for dcdc3
regulator: tps65218: Enable suspend configuration
regulator: tps65217: Enable suspend configuration
regulator: qcom_spmi: Add support for get_mode/set_mode on switches
...
Pull regmap updates from Mark Brown:
"Several small updates and API enhancements:
- provide transparent unrolling of bulk writes into individual writes
so they can be used with devices without raw formatting.
- fix compatibility between I2C controllers supporting block commands
and devices with more than 8 bit wide registers.
- add some helpers for iopoll-like functionality and workarounds for
weird interrupt controllers"
* tag 'regmap-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap:
regmap: add iopoll-like polling macro
regmap: Support bulk writes for devices without raw formatting
regmap-i2c: Use i2c block command only if register value width is 8 bit
regmap: irq: Add support to call client specific pre/post interrupt service
regmap: Add file patterns for regmap device tree bindings
Pull media updates from Mauro Carvalho Chehab:
- new framework support for HDMI CEC and remote control support
- new encoding codec driver for Mediatek SoC
- new frontend driver: helene tuner
- added support for NetUp almost universal devices, with supports
DVB-C/S/S2/T/T2 and ISDB-T
- the mn88472 frontend driver got promoted from staging
- a new driver for RCar video input
- some soc_camera legacy drivers got removed: timb, omap1, mx2, mx3
- lots of driver cleanups, improvements and fixups
* tag 'media/v4.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (377 commits)
[media] cec: always check all_device_types and features
[media] cec: poll should check if there is room in the tx queue
[media] vivid: support monitor all mode
[media] cec: fix test for unconfigured adapter in main message loop
[media] cec: limit the size of the transmit queue
[media] cec: zero unused msg part after msg->len
[media] cec: don't set fh to NULL in CEC_TRANSMIT
[media] cec: clear all status fields before transmit and always fill in sequence
[media] cec: CEC_RECEIVE overwrote the timeout field
[media] cxd2841er: Reading SNR for DVB-C added
[media] cxd2841er: Reading BER and UCB for DVB-C added
[media] cxd2841er: fix switch-case for DVB-C
[media] cxd2841er: fix signal strength scale for ISDB-T
[media] cxd2841er: adjust the dB scale for DVB-C
[media] cxd2841er: provide signal strength for DVB-C
[media] cxd2841er: fix BER report via DVBv5 stats API
[media] mb86a20s: apply mask to val after checking for read failure
[media] airspy: fix error logic during device register
[media] s5p-cec/TODO: add TODO item
[media] cec/TODO: drop comment about sphinx documentation
...
Pull pstore subsystem updates from Kees Cook:
"This expands the supported compressors, fixes some bugs, and finally
adds DT bindings"
* tag 'pstore-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
pstore/ram: add Device Tree bindings
efi-pstore: implement efivars_pstore_exit()
pstore: drop file opened reference count
pstore: add lzo/lz4 compression support
pstore: Cleanup pstore_dump()
pstore: Enable compression on normal path (again)
ramoops: Only unregister when registered
Pull ext4 updates from Ted Ts'o:
"The major change this cycle is deleting ext4's copy of the file system
encryption code and switching things over to using the copies in
fs/crypto. I've updated the MAINTAINERS file to add an entry for
fs/crypto listing Jaeguk Kim and myself as the maintainers.
There are also a number of bug fixes, most notably for some problems
found by American Fuzzy Lop (AFL) courtesy of Vegard Nossum. Also
fixed is a writeback deadlock detected by generic/130, and some
potential races in the metadata checksum code"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (21 commits)
ext4: verify extent header depth
ext4: short-cut orphan cleanup on error
ext4: fix reference counting bug on block allocation error
MAINTAINRES: fs-crypto maintainers update
ext4 crypto: migrate into vfs's crypto engine
ext2: fix filesystem deadlock while reading corrupted xattr block
ext4: fix project quota accounting without quota limits enabled
ext4: validate s_reserved_gdt_blocks on mount
ext4: remove unused page_idx
ext4: don't call ext4_should_journal_data() on the journal inode
ext4: Fix WARN_ON_ONCE in ext4_commit_super()
ext4: fix deadlock during page writeback
ext4: correct error value of function verifying dx checksum
ext4: avoid modifying checksum fields directly during checksum verification
ext4: check for extents that wrap around
jbd2: make journal y2038 safe
jbd2: track more dependencies on transaction commit
jbd2: move lockdep tracking to journal_s
jbd2: move lockdep instrumentation for jbd2 handles
ext4: respect the nobarrier mount option in nojournal mode
...
Pull ACPI updates from Rafael Wysocki:
"The new feaures here are the support for ACPI overlays (allowing ACPI
tables to be loaded at any time from EFI variables or via configfs)
and the LPI (Low-Power Idle) support. Also notable is the ACPI-based
NUMA support for ARM64.
Apart from that we have two new drivers, for the DPTF (Dynamic Power
and Thermal Framework) power participant device and for the Intel
Broxton WhiskeyCove PMIC, some more PMIC-related changes, support for
the Boot Error Record Table (BERT) in APEI and support for
platform-initiated graceful shutdown.
Plus two new pieces of documentation and usual assorted fixes and
cleanups in quite a few places.
Specifics:
- Support for ACPI SSDT overlays allowing Secondary System
Description Tables (SSDTs) to be loaded at any time from EFI
variables or via configfs (Octavian Purdila, Mika Westerberg).
- Support for the ACPI LPI (Low-Power Idle) feature introduced in
ACPI 6.0 and allowing processor idle states to be represented in
ACPI tables in a hierarchical way (with the help of Processor
Container objects) and support for ACPI idle states management on
ARM64, based on LPI (Sudeep Holla).
- General improvements of ACPI support for NUMA and ARM64 support for
ACPI-based NUMA (Hanjun Guo, David Daney, Robert Richter).
- General improvements of the ACPI table upgrade mechanism and ARM64
support for that feature (Aleksey Makarov, Jon Masters).
- Support for the Boot Error Record Table (BERT) in APEI and
improvements of kernel messages printed by the error injection code
(Huang Ying, Borislav Petkov).
- New driver for the Intel Broxton WhiskeyCove PMIC operation region
and support for the REGS operation region on Broxton, PMIC code
cleanups (Bin Gao, Felipe Balbi, Paul Gortmaker).
- New driver for the power participant device which is part of the
Dynamic Power and Thermal Framework (DPTF) and DPTF-related code
reorganization (Srinivas Pandruvada).
- Support for the platform-initiated graceful shutdown feature
introduced in ACPI 6.1 (Prashanth Prakash).
- ACPI button driver update related to lid input events generated
automatically on initialization and system resume that have been
problematic for some time (Lv Zheng).
- ACPI EC driver cleanups (Lv Zheng).
- Documentation of the ACPICA release automation process and the
in-kernel ACPI AML debugger (Lv Zheng).
- New blacklist entry and two fixes for the ACPI backlight driver
(Alex Hung, Arvind Yadav, Ralf Gerbig).
- Cleanups of the ACPI pci_slot driver (Joe Perches, Paul Gortmaker).
- ACPI CPPC code changes to make it more robust against possible
defects in ACPI tables and new symbol definitions for PCC (Hoan
Tran).
- System reboot code modification to execute the ACPI _PTS (Prepare
To Sleep) method in addition to _TTS (Ocean He).
- ACPICA-related change to carry out lock ordering checks in ACPICA
if ACPICA debug is enabled in the kernel (Lv Zheng).
- Assorted minor fixes and cleanups (Andy Shevchenko, Baoquan He,
Bhaktipriya Shridhar, Paul Gortmaker, Rafael Wysocki)"
* tag 'acpi-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (71 commits)
ACPI: enable ACPI_PROCESSOR_IDLE on ARM64
arm64: add support for ACPI Low Power Idle(LPI)
drivers: firmware: psci: initialise idle states using ACPI LPI
cpuidle: introduce CPU_PM_CPU_IDLE_ENTER macro for ARM{32, 64}
arm64: cpuidle: drop __init section marker to arm_cpuidle_init
ACPI / processor_idle: Add support for Low Power Idle(LPI) states
ACPI / processor_idle: introduce ACPI_PROCESSOR_CSTATE
ACPI / DPTF: move int340x_thermal.c to the DPTF folder
ACPI / DPTF: Add DPTF power participant driver
ACPI / lpat: make it explicitly non-modular
ACPI / dock: make dock explicitly non-modular
ACPI / PCI: make pci_slot explicitly non-modular
ACPI / PMIC: remove modular references from non-modular code
ACPICA: Linux: Enable ACPI_MUTEX_DEBUG for Linux kernel
ACPI: Rename configfs.c to acpi_configfs.c to prevent link error
ACPI / debugger: Add AML debugger documentation
ACPI: Add documentation describing ACPICA release automation
ACPI: add support for loading SSDTs via configfs
ACPI: add support for configfs
efi / ACPI: load SSTDs from EFI variables
...
Pull power management updates from Rafael Wysocki:
"Again, the majority of changes go into the cpufreq subsystem, but
there are no big features this time. The cpufreq changes that stand
out somewhat are the governor interface rework and improvements
related to the handling of frequency tables. Apart from those, there
are fixes and new device/CPU IDs in drivers, cleanups and an
improvement of the new schedutil governor.
Next, there are some changes in the hibernation core, including a fix
for a nasty problem related to the MONITOR/MWAIT usage by CPU offline
during resume from hibernation, a few core improvements related to
memory management during resume, a couple of additional debug features
and cleanups.
Finally, we have some fixes and cleanups in the devfreq subsystem,
generic power domains framework improvements related to system
suspend/resume, support for some new chips in intel_idle and in the
power capping RAPL driver, a new version of the AnalyzeSuspend utility
and some assorted fixes and cleanups.
Specifics:
- Rework the cpufreq governor interface to make it more
straightforward and modify the conservative governor to avoid using
transition notifications (Rafael Wysocki).
- Rework the handling of frequency tables by the cpufreq core to make
it more efficient (Viresh Kumar).
- Modify the schedutil governor to reduce the number of wakeups it
causes to occur in cases when the CPU frequency doesn't need to be
changed (Steve Muckle, Viresh Kumar).
- Fix some minor issues and clean up code in the cpufreq core and
governors (Rafael Wysocki, Viresh Kumar).
- Add Intel Broxton support to the intel_pstate driver (Srinivas
Pandruvada).
- Fix problems related to the config TDP feature and to the validity
of the MSR_HWP_INTERRUPT register in intel_pstate (Jan Kiszka,
Srinivas Pandruvada).
- Make intel_pstate update the cpu_frequency tracepoint even if the
frequency doesn't change to avoid confusing powertop (Rafael
Wysocki).
- Clean up the usage of __init/__initdata in intel_pstate, mark some
of its internal variables as __read_mostly and drop an unused
structure element from it (Jisheng Zhang, Carsten Emde).
- Clean up the usage of some duplicate MSR symbols in intel_pstate
and turbostat (Srinivas Pandruvada).
- Update/fix the powernv, s3c24xx and mvebu cpufreq drivers (Akshay
Adiga, Viresh Kumar, Ben Dooks).
- Fix a regression (introduced during the 4.5 cycle) in the
pcc-cpufreq driver by reverting the problematic commit (Andreas
Herrmann).
- Add support for Intel Denverton to intel_idle, clean up Broxton
support in it and make it explicitly non-modular (Jacob Pan, Jan
Beulich, Paul Gortmaker).
- Add support for Denverton and Ivy Bridge server to the Intel RAPL
power capping driver and make it more careful about the handing of
MSRs that may not be present (Jacob Pan, Xiaolong Wang).
- Fix resume from hibernation on x86-64 by making the CPU offline
during resume avoid using MONITOR/MWAIT in the "play dead" loop
which may lead to an inadvertent "revival" of a "dead" CPU and a
page fault leading to a kernel crash from it (Rafael Wysocki).
- Make memory management during resume from hibernation more
straightforward (Rafael Wysocki).
- Add debug features that should help to detect problems related to
hibernation and resume from it (Rafael Wysocki, Chen Yu).
- Clean up hibernation core somewhat (Rafael Wysocki).
- Prevent KASAN from instrumenting the hibernation core which leads
to large numbers of false-positives from it (James Morse).
- Prevent PM (hibernate and suspend) notifiers from being called
during the cleanup phase if they have not been called during the
corresponding preparation phase which is possible if one of the
other notifiers returns an error at that time (Lianwei Wang).
- Improve suspend-related debug printout in the tasks freezer and
clean up suspend-related console handling (Roger Lu, Borislav
Petkov).
- Update the AnalyzeSuspend script in the kernel sources to version
4.2 (Todd Brandt).
- Modify the generic power domains framework to make it handle system
suspend/resume better (Ulf Hansson).
- Make the runtime PM framework avoid resuming devices synchronously
when user space changes the runtime PM settings for them and
improve its error reporting (Rafael Wysocki, Linus Walleij).
- Fix error paths in devfreq drivers (exynos, exynos-ppmu,
exynos-bus) and in the core, make some devfreq code explicitly
non-modular and change some of it into tristate (Bartlomiej
Zolnierkiewicz, Peter Chen, Paul Gortmaker).
- Add DT support to the generic PM clocks management code and make it
export some more symbols (Jon Hunter, Paul Gortmaker).
- Make the PCI PM core code slightly more robust against possible
driver errors (Andy Shevchenko).
- Make it possible to change DESTDIR and PREFIX in turbostat (Andy
Shevchenko)"
* tag 'pm-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (89 commits)
Revert "cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency"
PM / hibernate: Introduce test_resume mode for hibernation
cpufreq: export cpufreq_driver_resolve_freq()
cpufreq: Disallow ->resolve_freq() for drivers providing ->target_index()
PCI / PM: check all fields in pci_set_platform_pm()
cpufreq: acpi-cpufreq: use cached frequency mapping when possible
cpufreq: schedutil: map raw required frequency to driver frequency
cpufreq: add cpufreq_driver_resolve_freq()
cpufreq: intel_pstate: Check cpuid for MSR_HWP_INTERRUPT
intel_pstate: Update cpu_frequency tracepoint every time
cpufreq: intel_pstate: clean remnant struct element
PM / tools: scripts: AnalyzeSuspend v4.2
x86 / hibernate: Use hlt_play_dead() when resuming from hibernation
cpufreq: powernv: Replacing pstate_id with frequency table index
intel_pstate: Fix MSR_CONFIG_TDP_x addressing in core_get_max_pstate()
PM / hibernate: Image data protection during restoration
PM / hibernate: Add missing braces in __register_nosave_region()
PM / hibernate: Clean up comments in snapshot.c
PM / hibernate: Clean up function headers in snapshot.c
PM / hibernate: Add missing braces in hibernate_setup()
...
Pull device mapper updates from Mike Snitzer:
- initially based on Jens' 'for-4.8/core' (given all the flag churn)
and later merged with 'for-4.8/core' to pickup the QUEUE_FLAG_DAX
commits that DM depends on to provide its DAX support
- clean up the bio-based vs request-based DM core code by moving the
request-based DM core code out to dm-rq.[hc]
- reinstate bio-based support in the DM multipath target (done with the
idea that fast storage like NVMe over Fabrics could benefit) -- while
preserving support for request_fn and blk-mq request-based DM mpath
- SCSI and DM multipath persistent reservation fixes that were
coordinated with Martin Petersen.
- the DM raid target saw the most extensive change this cycle; it now
provides reshape and takeover support (by layering ontop of the
corresponding MD capabilities)
- DAX support for DM core and the linear, stripe and error targets
- a DM thin-provisioning block discard vs allocation race fix that
addresses potential for corruption
- a stable fix for DM verity-fec's block calculation during decode
- a few cleanups and fixes to DM core and various targets
* tag 'dm-4.8-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (73 commits)
dm: allow bio-based table to be upgraded to bio-based with DAX support
dm snap: add fake origin_direct_access
dm stripe: add DAX support
dm error: add DAX support
dm linear: add DAX support
dm: add infrastructure for DAX support
dm thin: fix a race condition between discarding and provisioning a block
dm btree: fix a bug in dm_btree_find_next_single()
dm raid: fix random optimal_io_size for raid0
dm raid: address checkpatch.pl complaints
dm: call PR reserve/unreserve on each underlying device
sd: don't use the ALL_TG_PT bit for reservations
dm: fix second blk_delay_queue() parameter to be in msec units not jiffies
dm raid: change logical functions to actually return bool
dm raid: use rdev_for_each in status
dm raid: use rs->raid_disks to avoid memory leaks on free
dm raid: support delta_disks for raid1, fix table output
dm raid: enhance reshape check and factor out reshape setup
dm raid: allow resize during recovery
dm raid: fix rs_is_recovering() to allow for lvextend
...
Randy reported below build error.
> In file included from ../include/linux/balloon_compaction.h:48:0,
> from ../mm/balloon_compaction.c:11:
> ../include/linux/compaction.h:237:51: warning: 'struct node' declared inside parameter list [enabled by default]
> static inline int compaction_register_node(struct node *node)
> ../include/linux/compaction.h:237:51: warning: its scope is only this definition or declaration, which is probably not what you want [enabled by default]
> ../include/linux/compaction.h:242:54: warning: 'struct node' declared inside parameter list [enabled by default]
> static inline void compaction_unregister_node(struct node *node)
>
It was caused by non-lru page migration which needs compaction.h but
compaction.h doesn't include any header to be standalone.
I think proper header for non-lru page migration is migrate.h rather
than compaction.h because migrate.h has already headers needed to work
non-lru page migration indirectly like isolate_mode_t, migrate_mode
MIGRATEPAGE_SUCCESS.
[akpm@linux-foundation.org: revert mm-balloon-use-general-non-lru-movable-page-feature-fix.patch temp fix]
Link: http://lkml.kernel.org/r/20160610003304.GE29779@bbox
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Gioh Kim <gi-oh.kim@profitbricks.com>
Cc: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Even if user asked to allocate huge pages always (huge=always), we
should be able to free up some memory by splitting pages which are
partly byound i_size if memory presure comes or once we hit limit on
filesystem size (-o size=).
In order to do this we maintain per-superblock list of inodes, which
potentially have huge pages on the border of file size.
Per-fs shrinker can reclaim memory by splitting such pages.
If we hit -ENOSPC during shmem_getpage_gfp(), we try to split a page to
free up space on the filesystem and retry allocation if it succeed.
Link: http://lkml.kernel.org/r/1466021202-61880-37-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch extends khugepaged to support collapse of tmpfs/shmem pages.
We share fair amount of infrastructure with anon-THP collapse.
Few design points:
- First we are looking for VMA which can be suitable for mapping huge
page;
- If the VMA maps shmem file, the rest scan/collapse operations
operates on page cache, not on page tables as in anon VMA case.
- khugepaged_scan_shmem() finds a range which is suitable for huge
page. The scan is lockless and shouldn't disturb system too much.
- once the candidate for collapse is found, collapse_shmem() attempts
to create a huge page:
+ scan over radix tree, making the range point to new huge page;
+ new huge page is not-uptodate, locked and freezed (refcount
is 0), so nobody can touch them until we say so.
+ we swap in pages during the scan. khugepaged_scan_shmem()
filters out ranges with more than khugepaged_max_ptes_swap
swapped out pages. It's HPAGE_PMD_NR/8 by default.
+ old pages are isolated, unmapped and put to local list in case
to be restored back if collapse failed.
- if collapse succeed, we retract pte page tables from VMAs where huge
pages mapping is possible. The huge page will be mapped as PMD on
next minor fault into the range.
Link: http://lkml.kernel.org/r/1466021202-61880-35-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Here's basic implementation of huge pages support for shmem/tmpfs.
It's all pretty streight-forward:
- shmem_getpage() allcoates huge page if it can and try to inserd into
radix tree with shmem_add_to_page_cache();
- shmem_add_to_page_cache() puts the page onto radix-tree if there's
space for it;
- shmem_undo_range() removes huge pages, if it fully within range.
Partial truncate of huge pages zero out this part of THP.
This have visible effect on fallocate(FALLOC_FL_PUNCH_HOLE)
behaviour. As we don't really create hole in this case,
lseek(SEEK_HOLE) may have inconsistent results depending what
pages happened to be allocated.
- no need to change shmem_fault: core-mm will map an compound page as
huge if VMA is suitable;
Link: http://lkml.kernel.org/r/1466021202-61880-30-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Provide a shmem_get_unmapped_area method in file_operations, called at
mmap time to decide the mapping address. It could be conditional on
CONFIG_TRANSPARENT_HUGEPAGE, but save #ifdefs in other places by making
it unconditional.
shmem_get_unmapped_area() first calls the usual mm->get_unmapped_area
(which we treat as a black box, highly dependent on architecture and
config and executable layout). Lots of conditions, and in most cases it
just goes with the address that chose; but when our huge stars are
rightly aligned, yet that did not provide a suitable address, go back to
ask for a larger arena, within which to align the mapping suitably.
There have to be some direct calls to shmem_get_unmapped_area(), not via
the file_operations: because of the way shmem_zero_setup() is called to
create a shmem object late in the mmap sequence, when MAP_SHARED is
requested with MAP_ANONYMOUS or /dev/zero. Though this only matters
when /proc/sys/vm/shmem_huge has been set.
Link: http://lkml.kernel.org/r/1466021202-61880-29-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds new mount option "huge=". It can have following values:
- "always":
Attempt to allocate huge pages every time we need a new page;
- "never":
Do not allocate huge pages;
- "within_size":
Only allocate huge page if it will be fully within i_size.
Also respect fadvise()/madvise() hints;
- "advise:
Only allocate huge pages if requested with fadvise()/madvise();
Default is "never" for now.
"mount -o remount,huge= /mountpoint" works fine after mount: remounting
huge=never will not attempt to break up huge pages at all, just stop
more from being allocated.
No new config option: put this under CONFIG_TRANSPARENT_HUGEPAGE, which
is the appropriate option to protect those who don't want the new bloat,
and with which we shall share some pmd code.
Prohibit the option when !CONFIG_TRANSPARENT_HUGEPAGE, just as mpol is
invalid without CONFIG_NUMA (was hidden in mpol_parse_str(): make it
explicit).
Allow enabling THP only if the machine has_transparent_hugepage().
But what about Shmem with no user-visible mount? SysV SHM, memfds,
shared anonymous mmaps (of /dev/zero or MAP_ANONYMOUS), GPU drivers' DRM
objects, Ashmem. Though unlikely to suit all usages, provide sysfs knob
/sys/kernel/mm/transparent_hugepage/shmem_enabled to experiment with
huge on those.
And allow shmem_enabled two further values:
- "deny":
For use in emergencies, to force the huge option off from
all mounts;
- "force":
Force the huge option on for all - very useful for testing;
Based on patch by Hugh Dickins.
Link: http://lkml.kernel.org/r/1466021202-61880-28-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Vladimir has noticed that we might declare memcg oom even during
readahead because read_pages only uses GFP_KERNEL (with mapping_gfp
restriction) while __do_page_cache_readahead uses
page_cache_alloc_readahead which adds __GFP_NORETRY to prevent from
OOMs. This gfp mask discrepancy is really unfortunate and easily
fixable. Drop page_cache_alloc_readahead() which only has one user and
outsource the gfp_mask logic into readahead_gfp_mask and propagate this
mask from __do_page_cache_readahead down to read_pages.
This alone would have only very limited impact as most filesystems are
implementing ->readpages and the common implementation mpage_readpages
does GFP_KERNEL (with mapping_gfp restriction) again. We can tell it to
use readahead_gfp_mask instead as this function is called only during
readahead as well. The same applies to read_cache_pages.
ext4 has its own ext4_mpage_readpages but the path which has pages !=
NULL can use the same gfp mask. Btrfs, cifs, f2fs and orangefs are
doing a very similar pattern to mpage_readpages so the same can be
applied to them as well.
[akpm@linux-foundation.org: coding-style fixes]
[mhocko@suse.com: restrict gfp mask in mpage_alloc]
Link: http://lkml.kernel.org/r/20160610074223.GC32285@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/1465301556-26431-1-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Chris Mason <clm@fb.com>
Cc: Steve French <sfrench@samba.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Jan Kara <jack@suse.cz>
Cc: Mike Marshall <hubcap@omnibond.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Changman Lee <cm224.lee@samsung.com>
Cc: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Correct the function parameters alignment, since original code already
use both tabs and white spaces together for the incorrect parameters
alignment functions.
If one line can hold one statement within 80 columns, let it in one line
(original code did not consider about the tabs/spaces for 2nd line when
a statement is separated into 2 lines).
Try to let '' aligned within one macro, since all related lines are
short enough.
Remove useless statement "idx = 0;", and always assign rgn within the
'for' statement.
Link: http://lkml.kernel.org/r/1464904899-1714-1-git-send-email-chengang@emindsoft.com.cn
Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I have noticed that frontswap.h first declares "frontswap_enabled" as
extern bool variable, and then overrides it with "#define
frontswap_enabled (1)" for CONFIG_FRONTSWAP=Y or (0) when disabled. The
bool variable isn't actually instantiated anywhere.
This all looks like an unfinished attempt to make frontswap_enabled
reflect whether a backend is instantiated. But in the current state,
all frontswap hooks call unconditionally into frontswap.c just to check
if frontswap_ops is non-NULL. This should at least be checked inline,
but we can further eliminate the overhead when CONFIG_FRONTSWAP is
enabled and no backend registered, using a static key that is initially
disabled, and gets enabled only upon first backend registration.
Thus, checks for "frontswap_enabled" are replaced with
"frontswap_enabled()" wrapping the static key check. There are two
exceptions:
- xen's selfballoon_process() was testing frontswap_enabled in code guarded
by #ifdef CONFIG_FRONTSWAP, which was effectively always true when reachable.
The patch just removes this check. Using frontswap_enabled() does not sound
correct here, as this can be true even without xen's own backend being
registered.
- in SYSCALL_DEFINE2(swapon), change the check to IS_ENABLED(CONFIG_FRONTSWAP)
as it seems the bitmap allocation cannot currently be postponed until a
backend is registered. This means that frontswap will still have some
memory overhead by being configured, but without a backend.
After the patch, we can expect that some functions in frontswap.c are
called only when frontswap_ops is non-NULL. Change the checks there to
VM_BUG_ONs. While at it, convert other BUG_ONs to VM_BUG_ONs as
frontswap has been stable for some time.
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/1463152235-9717-1-git-send-email-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, to charge a non-slab allocation to kmemcg one has to use
alloc_kmem_pages helper with __GFP_ACCOUNT flag. A page allocated with
this helper should finally be freed using free_kmem_pages, otherwise it
won't be uncharged.
This API suits its current users fine, but it turns out to be impossible
to use along with page reference counting, i.e. when an allocation is
supposed to be freed with put_page, as it is the case with pipe or unix
socket buffers.
To overcome this limitation, this patch moves charging/uncharging to
generic page allocator paths, i.e. to __alloc_pages_nodemask and
free_pages_prepare, and zaps alloc/free_kmem_pages helpers. This way,
one can use any of the available page allocation functions to get the
allocated page charged to kmemcg - it's enough to pass __GFP_ACCOUNT,
just like in case of kmalloc and friends. A charged page will be
automatically uncharged on free.
To make it possible, we need to mark pages charged to kmemcg somehow.
To avoid introducing a new page flag, we make use of page->_mapcount for
marking such pages. Since pages charged to kmemcg are not supposed to
be mapped to userspace, it should work just fine. There are other
(ab)users of page->_mapcount - buddy and balloon pages - but we don't
conflict with them.
In case kmemcg is compiled out or not used at runtime, this patch
introduces no overhead to generic page allocator paths. If kmemcg is
used, it will be plus one gfp flags check on alloc and plus one
page->_mapcount check on free, which shouldn't hurt performance, because
the data accessed are hot.
Link: http://lkml.kernel.org/r/a9736d856f895bcb465d9f257b54efe32eda6f99.1464079538.git.vdavydov@virtuozzo.com
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, we store each page's allocation stacktrace on corresponding
page_ext structure and it requires a lot of memory. This causes the
problem that memory tight system doesn't work well if page_owner is
enabled. Moreover, even with this large memory consumption, we cannot
get full stacktrace because we allocate memory at boot time and just
maintain 8 stacktrace slots to balance memory consumption. We could
increase it to more but it would make system unusable or change system
behaviour.
To solve the problem, this patch uses stackdepot to store stacktrace.
It obviously provides memory saving but there is a drawback that
stackdepot could fail.
stackdepot allocates memory at runtime so it could fail if system has
not enough memory. But, most of allocation stack are generated at very
early time and there are much memory at this time. So, failure would
not happen easily. And, one failure means that we miss just one page's
allocation stacktrace so it would not be a big problem. In this patch,
when memory allocation failure happens, we store special stracktrace
handle to the page that is failed to save stacktrace. With it, user can
guess memory usage properly even if failure happens.
Memory saving looks as following. (4GB memory system with page_owner)
(before the patch -> after the patch)
static allocation:
92274688 bytes -> 25165824 bytes
dynamic allocation after boot + kernel build:
0 bytes -> 327680 bytes
total:
92274688 bytes -> 25493504 bytes
72% reduction in total.
Note that implementation looks complex than someone would imagine
because there is recursion issue. stackdepot uses page allocator and
page_owner is called at page allocation. Using stackdepot in page_owner
could re-call page allcator and then page_owner. That is a recursion.
To detect and avoid it, whenever we obtain stacktrace, recursion is
checked and page_owner is set to dummy information if found. Dummy
information means that this page is allocated for page_owner feature
itself (such as stackdepot) and it's understandable behavior for user.
[iamjoonsoo.kim@lge.com: mm-page_owner-use-stackdepot-to-store-stacktrace-v3]
Link: http://lkml.kernel.org/r/1464230275-25791-6-git-send-email-iamjoonsoo.kim@lge.com
Link: http://lkml.kernel.org/r/1466150259-27727-7-git-send-email-iamjoonsoo.kim@lge.com
Link: http://lkml.kernel.org/r/1464230275-25791-6-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We have allowed migration for only LRU pages until now and it was enough
to make high-order pages. But recently, embedded system(e.g., webOS,
android) uses lots of non-movable pages(e.g., zram, GPU memory) so we
have seen several reports about troubles of small high-order allocation.
For fixing the problem, there were several efforts (e,g,. enhance
compaction algorithm, SLUB fallback to 0-order page, reserved memory,
vmalloc and so on) but if there are lots of non-movable pages in system,
their solutions are void in the long run.
So, this patch is to support facility to change non-movable pages with
movable. For the feature, this patch introduces functions related to
migration to address_space_operations as well as some page flags.
If a driver want to make own pages movable, it should define three
functions which are function pointers of struct
address_space_operations.
1. bool (*isolate_page) (struct page *page, isolate_mode_t mode);
What VM expects on isolate_page function of driver is to return *true*
if driver isolates page successfully. On returing true, VM marks the
page as PG_isolated so concurrent isolation in several CPUs skip the
page for isolation. If a driver cannot isolate the page, it should
return *false*.
Once page is successfully isolated, VM uses page.lru fields so driver
shouldn't expect to preserve values in that fields.
2. int (*migratepage) (struct address_space *mapping,
struct page *newpage, struct page *oldpage, enum migrate_mode);
After isolation, VM calls migratepage of driver with isolated page. The
function of migratepage is to move content of the old page to new page
and set up fields of struct page newpage. Keep in mind that you should
indicate to the VM the oldpage is no longer movable via
__ClearPageMovable() under page_lock if you migrated the oldpage
successfully and returns 0. If driver cannot migrate the page at the
moment, driver can return -EAGAIN. On -EAGAIN, VM will retry page
migration in a short time because VM interprets -EAGAIN as "temporal
migration failure". On returning any error except -EAGAIN, VM will give
up the page migration without retrying in this time.
Driver shouldn't touch page.lru field VM using in the functions.
3. void (*putback_page)(struct page *);
If migration fails on isolated page, VM should return the isolated page
to the driver so VM calls driver's putback_page with migration failed
page. In this function, driver should put the isolated page back to the
own data structure.
4. non-lru movable page flags
There are two page flags for supporting non-lru movable page.
* PG_movable
Driver should use the below function to make page movable under
page_lock.
void __SetPageMovable(struct page *page, struct address_space *mapping)
It needs argument of address_space for registering migration family
functions which will be called by VM. Exactly speaking, PG_movable is
not a real flag of struct page. Rather than, VM reuses page->mapping's
lower bits to represent it.
#define PAGE_MAPPING_MOVABLE 0x2
page->mapping = page->mapping | PAGE_MAPPING_MOVABLE;
so driver shouldn't access page->mapping directly. Instead, driver
should use page_mapping which mask off the low two bits of page->mapping
so it can get right struct address_space.
For testing of non-lru movable page, VM supports __PageMovable function.
However, it doesn't guarantee to identify non-lru movable page because
page->mapping field is unified with other variables in struct page. As
well, if driver releases the page after isolation by VM, page->mapping
doesn't have stable value although it has PAGE_MAPPING_MOVABLE (Look at
__ClearPageMovable). But __PageMovable is cheap to catch whether page
is LRU or non-lru movable once the page has been isolated. Because LRU
pages never can have PAGE_MAPPING_MOVABLE in page->mapping. It is also
good for just peeking to test non-lru movable pages before more
expensive checking with lock_page in pfn scanning to select victim.
For guaranteeing non-lru movable page, VM provides PageMovable function.
Unlike __PageMovable, PageMovable functions validates page->mapping and
mapping->a_ops->isolate_page under lock_page. The lock_page prevents
sudden destroying of page->mapping.
Driver using __SetPageMovable should clear the flag via
__ClearMovablePage under page_lock before the releasing the page.
* PG_isolated
To prevent concurrent isolation among several CPUs, VM marks isolated
page as PG_isolated under lock_page. So if a CPU encounters PG_isolated
non-lru movable page, it can skip it. Driver doesn't need to manipulate
the flag because VM will set/clear it automatically. Keep in mind that
if driver sees PG_isolated page, it means the page have been isolated by
VM so it shouldn't touch page.lru field. PG_isolated is alias with
PG_reclaim flag so driver shouldn't use the flag for own purpose.
[opensource.ganesh@gmail.com: mm/compaction: remove local variable is_lru]
Link: http://lkml.kernel.org/r/20160618014841.GA7422@leo-test
Link: http://lkml.kernel.org/r/1464736881-24886-3-git-send-email-minchan@kernel.org
Signed-off-by: Gioh Kim <gi-oh.kim@profitbricks.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: John Einar Reitan <john.reitan@foss.arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Implements freelist randomization for the SLUB allocator. It was
previous implemented for the SLAB allocator. Both use the same
configuration option (CONFIG_SLAB_FREELIST_RANDOM).
The list is randomized during initialization of a new set of pages. The
order on different freelist sizes is pre-computed at boot for
performance. Each kmem_cache has its own randomized freelist.
This security feature reduces the predictability of the kernel SLUB
allocator against heap overflows rendering attacks much less stable.
For example these attacks exploit the predictability of the heap:
- Linux Kernel CAN SLUB overflow (https://goo.gl/oMNWkU)
- Exploiting Linux Kernel Heap corruptions (http://goo.gl/EXLn95)
Performance results:
slab_test impact is between 3% to 4% on average for 100000 attempts
without smp. It is a very focused testing, kernbench show the overall
impact on the system is way lower.
Before:
Single thread testing
=====================
1. Kmalloc: Repeatedly allocate then free test
100000 times kmalloc(8) -> 49 cycles kfree -> 77 cycles
100000 times kmalloc(16) -> 51 cycles kfree -> 79 cycles
100000 times kmalloc(32) -> 53 cycles kfree -> 83 cycles
100000 times kmalloc(64) -> 62 cycles kfree -> 90 cycles
100000 times kmalloc(128) -> 81 cycles kfree -> 97 cycles
100000 times kmalloc(256) -> 98 cycles kfree -> 121 cycles
100000 times kmalloc(512) -> 95 cycles kfree -> 122 cycles
100000 times kmalloc(1024) -> 96 cycles kfree -> 126 cycles
100000 times kmalloc(2048) -> 115 cycles kfree -> 140 cycles
100000 times kmalloc(4096) -> 149 cycles kfree -> 171 cycles
2. Kmalloc: alloc/free test
100000 times kmalloc(8)/kfree -> 70 cycles
100000 times kmalloc(16)/kfree -> 70 cycles
100000 times kmalloc(32)/kfree -> 70 cycles
100000 times kmalloc(64)/kfree -> 70 cycles
100000 times kmalloc(128)/kfree -> 70 cycles
100000 times kmalloc(256)/kfree -> 69 cycles
100000 times kmalloc(512)/kfree -> 70 cycles
100000 times kmalloc(1024)/kfree -> 73 cycles
100000 times kmalloc(2048)/kfree -> 72 cycles
100000 times kmalloc(4096)/kfree -> 71 cycles
After:
Single thread testing
=====================
1. Kmalloc: Repeatedly allocate then free test
100000 times kmalloc(8) -> 57 cycles kfree -> 78 cycles
100000 times kmalloc(16) -> 61 cycles kfree -> 81 cycles
100000 times kmalloc(32) -> 76 cycles kfree -> 93 cycles
100000 times kmalloc(64) -> 83 cycles kfree -> 94 cycles
100000 times kmalloc(128) -> 106 cycles kfree -> 107 cycles
100000 times kmalloc(256) -> 118 cycles kfree -> 117 cycles
100000 times kmalloc(512) -> 114 cycles kfree -> 116 cycles
100000 times kmalloc(1024) -> 115 cycles kfree -> 118 cycles
100000 times kmalloc(2048) -> 147 cycles kfree -> 131 cycles
100000 times kmalloc(4096) -> 214 cycles kfree -> 161 cycles
2. Kmalloc: alloc/free test
100000 times kmalloc(8)/kfree -> 66 cycles
100000 times kmalloc(16)/kfree -> 66 cycles
100000 times kmalloc(32)/kfree -> 66 cycles
100000 times kmalloc(64)/kfree -> 66 cycles
100000 times kmalloc(128)/kfree -> 65 cycles
100000 times kmalloc(256)/kfree -> 67 cycles
100000 times kmalloc(512)/kfree -> 67 cycles
100000 times kmalloc(1024)/kfree -> 64 cycles
100000 times kmalloc(2048)/kfree -> 67 cycles
100000 times kmalloc(4096)/kfree -> 67 cycles
Kernbench, before:
Average Optimal load -j 12 Run (std deviation):
Elapsed Time 101.873 (1.16069)
User Time 1045.22 (1.60447)
System Time 88.969 (0.559195)
Percent CPU 1112.9 (13.8279)
Context Switches 189140 (2282.15)
Sleeps 99008.6 (768.091)
After:
Average Optimal load -j 12 Run (std deviation):
Elapsed Time 102.47 (0.562732)
User Time 1045.3 (1.34263)
System Time 88.311 (0.342554)
Percent CPU 1105.8 (6.49444)
Context Switches 189081 (2355.78)
Sleeps 99231.5 (800.358)
Link: http://lkml.kernel.org/r/1464295031-26375-3-git-send-email-thgarnie@google.com
Signed-off-by: Thomas Garnier <thgarnie@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The kernel heap allocators are using a sequential freelist making their
allocation predictable. This predictability makes kernel heap overflow
easier to exploit. An attacker can careful prepare the kernel heap to
control the following chunk overflowed.
For example these attacks exploit the predictability of the heap:
- Linux Kernel CAN SLUB overflow (https://goo.gl/oMNWkU)
- Exploiting Linux Kernel Heap corruptions (http://goo.gl/EXLn95)
***Problems that needed solving:
- Randomize the Freelist (singled linked) used in the SLUB allocator.
- Ensure good performance to encourage usage.
- Get best entropy in early boot stage.
***Parts:
- 01/02 Reorganize the SLAB Freelist randomization to share elements
with the SLUB implementation.
- 02/02 The SLUB Freelist randomization implementation. Similar approach
than the SLAB but tailored to the singled freelist used in SLUB.
***Performance data:
slab_test impact is between 3% to 4% on average for 100000 attempts
without smp. It is a very focused testing, kernbench show the overall
impact on the system is way lower.
Before:
Single thread testing
=====================
1. Kmalloc: Repeatedly allocate then free test
100000 times kmalloc(8) -> 49 cycles kfree -> 77 cycles
100000 times kmalloc(16) -> 51 cycles kfree -> 79 cycles
100000 times kmalloc(32) -> 53 cycles kfree -> 83 cycles
100000 times kmalloc(64) -> 62 cycles kfree -> 90 cycles
100000 times kmalloc(128) -> 81 cycles kfree -> 97 cycles
100000 times kmalloc(256) -> 98 cycles kfree -> 121 cycles
100000 times kmalloc(512) -> 95 cycles kfree -> 122 cycles
100000 times kmalloc(1024) -> 96 cycles kfree -> 126 cycles
100000 times kmalloc(2048) -> 115 cycles kfree -> 140 cycles
100000 times kmalloc(4096) -> 149 cycles kfree -> 171 cycles
2. Kmalloc: alloc/free test
100000 times kmalloc(8)/kfree -> 70 cycles
100000 times kmalloc(16)/kfree -> 70 cycles
100000 times kmalloc(32)/kfree -> 70 cycles
100000 times kmalloc(64)/kfree -> 70 cycles
100000 times kmalloc(128)/kfree -> 70 cycles
100000 times kmalloc(256)/kfree -> 69 cycles
100000 times kmalloc(512)/kfree -> 70 cycles
100000 times kmalloc(1024)/kfree -> 73 cycles
100000 times kmalloc(2048)/kfree -> 72 cycles
100000 times kmalloc(4096)/kfree -> 71 cycles
After:
Single thread testing
=====================
1. Kmalloc: Repeatedly allocate then free test
100000 times kmalloc(8) -> 57 cycles kfree -> 78 cycles
100000 times kmalloc(16) -> 61 cycles kfree -> 81 cycles
100000 times kmalloc(32) -> 76 cycles kfree -> 93 cycles
100000 times kmalloc(64) -> 83 cycles kfree -> 94 cycles
100000 times kmalloc(128) -> 106 cycles kfree -> 107 cycles
100000 times kmalloc(256) -> 118 cycles kfree -> 117 cycles
100000 times kmalloc(512) -> 114 cycles kfree -> 116 cycles
100000 times kmalloc(1024) -> 115 cycles kfree -> 118 cycles
100000 times kmalloc(2048) -> 147 cycles kfree -> 131 cycles
100000 times kmalloc(4096) -> 214 cycles kfree -> 161 cycles
2. Kmalloc: alloc/free test
100000 times kmalloc(8)/kfree -> 66 cycles
100000 times kmalloc(16)/kfree -> 66 cycles
100000 times kmalloc(32)/kfree -> 66 cycles
100000 times kmalloc(64)/kfree -> 66 cycles
100000 times kmalloc(128)/kfree -> 65 cycles
100000 times kmalloc(256)/kfree -> 67 cycles
100000 times kmalloc(512)/kfree -> 67 cycles
100000 times kmalloc(1024)/kfree -> 64 cycles
100000 times kmalloc(2048)/kfree -> 67 cycles
100000 times kmalloc(4096)/kfree -> 67 cycles
Kernbench, before:
Average Optimal load -j 12 Run (std deviation):
Elapsed Time 101.873 (1.16069)
User Time 1045.22 (1.60447)
System Time 88.969 (0.559195)
Percent CPU 1112.9 (13.8279)
Context Switches 189140 (2282.15)
Sleeps 99008.6 (768.091)
After:
Average Optimal load -j 12 Run (std deviation):
Elapsed Time 102.47 (0.562732)
User Time 1045.3 (1.34263)
System Time 88.311 (0.342554)
Percent CPU 1105.8 (6.49444)
Context Switches 189081 (2355.78)
Sleeps 99231.5 (800.358)
This patch (of 2):
This commit reorganizes the previous SLAB freelist randomization to
prepare for the SLUB implementation. It moves functions that will be
shared to slab_common.
The entropy functions are changed to align with the SLUB implementation,
now using get_random_(int|long) functions. These functions were chosen
because they provide a bit more entropy early on boot and better
performance when specific arch instructions are not available.
[akpm@linux-foundation.org: fix build]
Link: http://lkml.kernel.org/r/1464295031-26375-2-git-send-email-thgarnie@google.com
Signed-off-by: Thomas Garnier <thgarnie@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
