linux/Documentation
Michal Hocko c76adee347 mm, thp, proc: report THP eligibility for each vma
[ Upstream commit 7635d9cbe8 ]

Userspace falls short when trying to find out whether a specific memory
range is eligible for THP.  There are usecases that would like to know
that
http://lkml.kernel.org/r/alpine.DEB.2.21.1809251248450.50347@chino.kir.corp.google.com
: This is used to identify heap mappings that should be able to fault thp
: but do not, and they normally point to a low-on-memory or fragmentation
: issue.

The only way to deduce this now is to query for hg resp.  nh flags and
confronting the state with the global setting.  Except that there is also
PR_SET_THP_DISABLE that might change the picture.  So the final logic is
not trivial.  Moreover the eligibility of the vma depends on the type of
VMA as well.  In the past we have supported only anononymous memory VMAs
but things have changed and shmem based vmas are supported as well these
days and the query logic gets even more complicated because the
eligibility depends on the mount option and another global configuration
knob.

Simplify the current state and report the THP eligibility in
/proc/<pid>/smaps for each existing vma.  Reuse
transparent_hugepage_enabled for this purpose.  The original
implementation of this function assumes that the caller knows that the vma
itself is supported for THP so make the core checks into
__transparent_hugepage_enabled and use it for existing callers.
__show_smap just use the new transparent_hugepage_enabled which also
checks the vma support status (please note that this one has to be out of
line due to include dependency issues).

[mhocko@kernel.org: fix oops with NULL ->f_mapping]
  Link: http://lkml.kernel.org/r/20181224185106.GC16738@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20181211143641.3503-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Paul Oppenheimer <bepvte@gmail.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-12-17 20:35:45 +01:00
..
ABI x86/bugs: Add ITLB_MULTIHIT bug infrastructure 2019-11-12 19:21:36 +01:00
accelerators
accounting
acpi
admin-guide USB: documentation: flags on usb-storage versus UAS 2019-12-17 20:34:30 +01:00
aoe
arm ARM: 8833/1: Ensure that NEON code always compiles with Clang 2019-04-05 22:33:08 +02:00
arm64 arm64: docs: Document SSBS HWCAP 2019-10-11 18:21:31 +02:00
auxdisplay
backlight
block
blockdev
bpf
bus-devices
cdrom
cgroup-v1
cma
connector
console
core-api idr: Change documentation license 2018-10-15 16:31:29 -04:00
cpu-freq
cpuidle
crypto
dev-tools
device-mapper dm raid: bump target version, update comments and documentation 2018-09-06 17:07:58 -04:00
devicetree rtc: dt-binding: abx80x: fix resistance scale 2019-12-13 08:51:36 +01:00
doc-guide
driver-api USB: core: Fix bug caused by duplicate interface PM usage counter 2019-05-08 07:21:44 +02:00
driver-model
early-userspace initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
EDID
extcon
fault-injection
fb uvesafb: Fix URLs in the documentation 2018-09-26 18:11:23 +02:00
features
filesystems mm, thp, proc: report THP eligibility for each vma 2019-12-17 20:35:45 +01:00
firmware_class
fmc
fpga
gpio
gpu
hid HID: doc: fix wrong data structure reference for UHID_OUTPUT 2019-12-05 09:20:36 +01:00
hwmon hwmon: (ina2xx) fix sysfs shunt resistor read access 2018-08-26 17:45:25 -07:00
i2c i2c: i801: Add support for Intel Comet Lake 2019-05-04 09:20:15 +02:00
ia64
ide
iio
infiniband
input
ioctl
isdn
kbuild kbuild: Fix LOADLIBES rename in Documentation/kbuild/makefiles.txt 2018-08-22 23:21:42 +09:00
kdump
kernel-hacking
laptops
leds
lightnvm
livepatch
locking
m68k
maintainer
md
media media: replace ADOBERGB by OPRGB 2018-11-13 11:08:54 -08:00
memory-devices
mic
mips
misc-devices
mmc
mtd
namespaces
netlabel
networking tcp: add tcp_min_snd_mss sysctl 2019-06-17 19:51:56 +02:00
nfc
nios2
nvdimm
nvmem
openrisc
parisc
PCI
pcmcia pcmcia: remove long deprecated pcmcia_request_exclusive_irq() function 2018-08-18 12:30:42 -07:00
perf
phy
platform
power
powerpc
pps
process stable-kernel-rules.rst: add link to networking patch queue 2019-03-23 20:10:10 +01:00
pti
ptp
rapidio
RCU
riscv
s390
scheduler sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices 2019-11-12 19:20:50 +01:00
scsi scsi: documentation: add scsi_mod.use_blk_mq to scsi-parameters 2018-08-27 12:26:10 -04:00
security
serial
sh
sound
sparc
sphinx doc: Cope with Sphinx logging deprecations 2019-06-09 09:17:21 +02:00
sphinx-static
spi
sysctl bpf: add bpf_jit_limit knob to restrict unpriv allocations 2019-05-31 06:46:03 -07:00
target
thermal
timers
trace
translations
usb USB: rio500: Remove Rio 500 kernel driver 2019-10-17 13:44:47 -07:00
userspace-api Documentation: Add section about CPU vulnerabilities for Spectre 2019-07-14 08:11:17 +02:00
virtual kvm: Convert kvm_lock to a mutex 2019-11-12 19:21:40 +01:00
vm
w1
watchdog
wimax
x86 x86/speculation/taa: Add documentation for TSX Async Abort 2019-11-12 19:21:34 +01:00
xtensa
.gitignore
00-INDEX
atomic_bitops.txt
atomic_t.txt x86/atomic: Fix smp_mb__{before,after}_atomic() 2019-07-26 09:14:08 +02:00
bt8xxgpio.txt
btmrvl.txt
bus-virt-phys-mapping.txt
Changes
clearing-warn-once.txt
CodingStyle
conf.py docs: Fix conf.py for Sphinx 2.0 2019-06-09 09:17:20 +02:00
cpu-load.txt
cputopology.txt
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
digsig.txt
DMA-API-HOWTO.txt
DMA-API.txt
DMA-attributes.txt
DMA-ISA-LPC.txt
docutils.conf
dontdiff
efi-stub.txt
eisa.txt
flexible-arrays.txt
futex-requeue-pi.txt
gcc-plugins.txt
highuid.txt
hw_random.txt
hwspinlock.txt
index.rst x86/speculation/mds: Add mds_clear_cpu_buffers() 2019-05-14 19:17:54 +02:00
intel_txt.txt
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt
iostats.txt
IPMI.txt
IRQ-affinity.txt
IRQ-domain.txt
IRQ.txt
irqflags-tracing.txt
isa.txt
isapnp.txt
kernel-per-CPU-kthreads.txt
kobject.txt
kprobes.txt
kref.txt
ldm.txt
lockup-watchdogs.txt
logo.gif
logo.txt
lsm.txt
lzo.txt
mailbox.txt
Makefile
memory-barriers.txt
memory-hotplug.txt
men-chameleon-bus.txt
nommu-mmap.txt
ntb.txt
numastat.txt
padata.txt
parport-lowlevel.txt
percpu-rw-semaphore.txt
phy.txt
pi-futex.txt
pnp.txt
preempt-locking.txt
pwm.txt
rbtree.txt
remoteproc.txt
rfkill.txt
robust-futex-ABI.txt
robust-futexes.txt futex: Update comments and docs about return values of arch futex code 2019-07-03 13:14:49 +02:00
rpmsg.txt
rtc.txt
SAK.txt
sgi-ioc4.txt
siphash.txt
SM501.txt
smsc_ece1099.txt
speculation.txt
static-keys.txt
SubmittingPatches
svga.txt
switchtec.txt
sync_file.txt
tee.txt
this_cpu_ops.txt
unaligned-memory-access.txt
vfio-mediated-device.txt
vfio.txt
video-output.txt
xillybus.txt
xz.txt
zorro.txt