linux/Documentation
Mel Gorman 24512228b7 mm: do not boost watermarks to avoid fragmentation for the DISCONTIG memory model
Mikulas Patocka reported that commit 1c30844d2d ("mm: reclaim small
amounts of memory when an external fragmentation event occurs") "broke"
memory management on parisc.

The machine is not NUMA but the DISCONTIG model creates three pgdats
even though it's a UMA machine for the following ranges

        0) Start 0x0000000000000000 End 0x000000003fffffff Size   1024 MB
        1) Start 0x0000000100000000 End 0x00000001bfdfffff Size   3070 MB
        2) Start 0x0000004040000000 End 0x00000040ffffffff Size   3072 MB

Mikulas reported:

	With the patch 1c30844d2, the kernel will incorrectly reclaim the
	first zone when it fills up, ignoring the fact that there are two
	completely free zones. Basiscally, it limits cache size to 1GiB.

	For example, if I run:
	# dd if=/dev/sda of=/dev/null bs=1M count=2048

	- with the proper kernel, there should be "Buffers - 2GiB"
	when this command finishes. With the patch 1c30844d2, buffers
	will consume just 1GiB or slightly more, because the kernel was
	incorrectly reclaiming them.

The page allocator and reclaim makes assumptions that pgdats really
represent NUMA nodes and zones represent ranges and makes decisions on
that basis.  Watermark boosting for small pgdats leads to unexpected
results even though this would have behaved reasonably on SPARSEMEM.

DISCONTIG is essentially deprecated and even parisc plans to move to
SPARSEMEM so there is no need to be fancy, this patch simply disables
watermark boosting by default on DISCONTIGMEM.

Link: http://lkml.kernel.org/r/20190419094335.GJ18914@techsingularity.net
Fixes: 1c30844d2d ("mm: reclaim small amounts of memory when an external fragmentation event occurs")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Tested-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-04-26 09:18:05 -07:00
..
ABI device-dax for 5.1 2019-03-16 13:05:32 -07:00
accelerators
accounting psi: clarify the units used in pressure files 2019-04-05 16:02:31 -10:00
acpi ACPI: Documentation: Fix path for acpidbg tool 2019-03-07 11:28:33 +01:00
admin-guide for-5.1/block-post-20190315 2019-03-16 12:36:39 -07:00
aoe
arm ARM: 8833/1: Ensure that NEON code always compiles with Clang 2019-02-12 15:20:09 +00:00
arm64 arm64 updates for 5.1: 2019-03-10 10:17:23 -07:00
auxdisplay
backlight
block block: document usage of bio iterator helpers 2019-02-15 08:40:12 -07:00
blockdev zram: idle writeback fixes and cleanup 2019-01-08 17:15:10 -08:00
bpf bpf, doc: fix BTF docs reflow of bullet list 2019-03-26 13:13:42 -07:00
bus-devices
cdrom Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
cgroup-v1 A fairly routine cycle for docs - lots of typo fixes, some new documents, 2019-03-09 09:56:17 -08:00
cma
connector
console Documentation: corrections to console/console.txt 2018-08-10 16:09:40 -06:00
core-api Merge branch 'akpm' (patches from Andrew) 2019-03-12 10:39:53 -07:00
cpu-freq Documentation: cpu-freq: Frequencies aren't always sorted 2018-11-07 13:29:04 +01:00
crypto crypto: skcipher - remove remnants of internal IV generators 2018-12-23 11:52:45 +08:00
dev-tools Documentation/dev-tools: Use gcc version number instead svn revision number 2019-01-14 17:25:41 -07:00
device-mapper dm cache: add support for discard passdown to the origin device 2019-03-05 14:53:52 -05:00
devicetree dt-bindings: add an explanation for internal phy-mode 2019-04-21 11:24:08 -07:00
doc-guide docs: kernel-doc: typo "if ... if" -> "if ... is" 2019-02-17 15:38:47 -07:00
driver-api dmaengine updates for v5.1-rc1 2019-03-14 09:11:54 -07:00
driver-model Merge branches 'clk-optional', 'clk-devm-clkdev-register', 'clk-allwinner', 'clk-meson' and 'clk-renesas' into clk-next 2019-03-08 10:27:21 -08:00
early-userspace Correct gen_init_cpio tool's documentation 2018-11-25 12:25:53 -07:00
EDID Docs/EDID: Calculate CRC while building the code 2018-11-06 07:36:22 -07:00
extcon
fault-injection doc: fault-injection: fix macro name in example 2019-01-07 15:36:11 -07:00
fb fbdev: fbmem: convert CONFIG_FB_LOGO_CENTER into a cmd line option 2019-01-16 17:42:35 +01:00
features Documentation/features: Add csky kernel features 2019-01-07 22:22:16 +08:00
filesystems vfs: Update mount API docs 2019-03-28 08:54:20 -07:00
firmware_class
fmc Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
fpga docs: fpga: add a document for FPGA Device Feature List (DFL) Framework Overview 2018-07-15 13:55:44 +02:00
gpio Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
gpu Merge drm/drm-next into drm-misc-next 2019-02-11 10:35:35 +01:00
hid HID: doc: fix wrong data structure reference for UHID_OUTPUT 2018-12-18 14:55:22 +01:00
hwmon A fairly routine cycle for docs - lots of typo fixes, some new documents, 2019-03-09 09:56:17 -08:00
i2c i2c: i801: Add support for Intel Comet Lake 2019-03-20 17:42:23 +01:00
ia64
ide Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
iio
infiniband Documentation/infiniband: update from locked to pinned_vm 2019-02-07 12:56:23 -07:00
input doc: Change LXR references to elixir.bootlin.com 2019-02-01 16:05:03 -07:00
interconnect interconnect: Add generic on-chip interconnect API 2019-01-22 13:37:25 +01:00
ioctl seccomp: add a return code to trap to userspace 2018-12-11 16:28:41 -08:00
isdn Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
kbuild kbuild: force all architectures except um to include mandatory-y 2019-03-17 12:56:32 +09:00
kdump kdump: Document kernel data exported in the vmcoreinfo note 2019-01-15 11:05:28 +01:00
kernel-hacking doc:it_IT: translation for kernel-hacking 2018-07-26 16:21:09 -06:00
laptops Documentation: fix lg-laptop.rst warnings 2019-02-11 08:27:47 -07:00
leds Documentation: Use "while" instead of "whilst" 2018-11-20 09:30:43 -07:00
lightnvm
livepatch livepatch: Remove signal sysfs attribute 2019-01-16 22:09:33 +01:00
locking Documentation/locking/lockdep: Drop last two chars of sample states 2019-03-04 12:55:18 -07:00
m68k Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
maintainer
md
media Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2019-04-19 10:28:27 -07:00
memory-devices
mic
mips Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
misc-devices Documentation: add ibmvmc to toctree(index) and fix warnings 2019-01-14 08:37:17 -07:00
mmc Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
mtd Documentation: mtd: remove stale pxa3xx NAND controller documentation 2018-09-04 23:37:38 +02:00
namespaces
netlabel Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
networking Documentation: decnet: remove reference to CONFIG_DECNET_ROUTE_FWMARK 2019-04-21 11:25:11 -07:00
nfc
nios2
nvdimm libnvdimm/security: Add documentation for nvdimm security support 2018-12-21 12:44:41 -08:00
nvmem Documentation: nvmem: document cell tables and lookup entries 2018-09-28 15:14:54 +02:00
openrisc
parisc Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
PCI pci-v4.20-changes 2018-10-25 06:50:48 -07:00
pcmcia pcmcia: remove long deprecated pcmcia_request_exclusive_irq() function 2018-08-18 12:30:42 -07:00
perf Documentation: perf: Add documentation for ThunderX2 PMU uncore driver 2018-12-06 12:29:47 +00:00
phy
platform
power PM/EM: Document the Energy Model framework 2019-01-27 12:29:37 +01:00
powerpc powerpc/fadump: Reservationless firmware assisted dump 2018-12-21 11:32:49 +11:00
pps
process A fairly routine cycle for docs - lots of typo fixes, some new documents, 2019-03-09 09:56:17 -08:00
pti
ptp
rapidio
RCU A fairly routine cycle for docs - lots of typo fixes, some new documents, 2019-03-09 09:56:17 -08:00
riscv
s390 Documentation: Use "while" instead of "whilst" 2018-11-20 09:30:43 -07:00
scheduler sched/doc: Document Energy Aware Scheduling 2019-01-27 12:29:37 +01:00
scsi scsi: ufs-bsg: Allow reading descriptors 2019-02-27 09:00:02 -05:00
security doc: security: Add kern-doc for lsm_hooks.h 2019-02-22 08:54:09 -07:00
serial Documentation: Use "while" instead of "whilst" 2018-11-20 09:30:43 -07:00
sh sh: remove board_time_init() callback 2018-12-18 16:13:04 +01:00
sound ASoC: More changes for v5.1 2019-02-28 13:30:55 +01:00
sparc
sphinx Documentation/sphinx: allow "functions" with no parameters 2018-06-30 07:52:42 -06:00
sphinx-static docs: improve readability for people with poorer eyesight 2018-10-07 09:16:50 -06:00
spi pxa2xx: replace spi_master with spi_controller 2019-01-23 10:59:56 +00:00
sysctl mm: do not boost watermarks to avoid fragmentation for the DISCONTIG memory model 2019-04-26 09:18:05 -07:00
target scsi: target/core: Remove the write_pending_status() callback function 2019-02-04 21:23:59 -05:00
thermal Documentation: Use "while" instead of "whilst" 2018-11-20 09:30:43 -07:00
timers Docs: Correct /proc/stat path 2019-02-22 08:50:17 -07:00
trace doc: trace: Fix documentation for uprobe_profile 2019-02-21 10:28:55 -05:00
translations A fairly routine cycle for docs - lots of typo fixes, some new documents, 2019-03-09 09:56:17 -08:00
usb usb: core: add option of only authorizing internal devices 2019-02-22 09:27:55 +01:00
userspace-api x86/speculation: Add PR_SPEC_DISABLE_NOEXEC 2019-01-29 22:11:49 +01:00
virtual Documentation: kvm: clarify KVM_SET_USER_MEMORY_REGION 2019-03-28 17:30:11 +01:00
vm docs: Use underscore not hyphen in label 2019-02-01 16:04:01 -07:00
w1 Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00
watchdog Documentation/watchdog: Add documentation mlx-wdt driver 2019-03-02 15:28:20 +01:00
wimax
x86 x86/resctrl: Avoid confusion over the new X86_RESCTRL config 2019-02-02 10:34:52 +01:00
xilinx Documentation: xilinx: Add documentation for eemi APIs 2018-10-09 13:26:05 +02:00
xtensa xtensa: document boot parameter passing 2019-02-03 18:06:19 -08:00
.gitignore
atomic_bitops.txt
atomic_t.txt
bt8xxgpio.txt
btmrvl.txt
bus-virt-phys-mapping.txt
Changes
clearing-warn-once.txt
CodingStyle
conf.py This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
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 Documentation/DMA-API-HOWTO: update dma_mask sections 2019-02-20 07:29:47 -07:00
DMA-API.txt virtio: fixes, cleanups 2019-03-10 12:47:57 -07:00
DMA-attributes.txt
DMA-ISA-LPC.txt Documentation/DMA-ISA-LPC: fix an incorrect reference 2019-02-11 08:23:07 -07:00
docutils.conf
dontdiff kernel/configs: use .incbin directive to embed config_data.gz 2019-03-07 18:32:02 -08:00
efi-stub.txt efi_stub: update documentation on dtb= parameter 2018-09-09 14:46:44 -06:00
eisa.txt
futex-requeue-pi.txt
gcc-plugins.txt
highuid.txt
hw_random.txt
hwspinlock.txt
index.rst Documentation: add ibmvmc to toctree(index) and fix warnings 2019-01-14 08:37:17 -07:00
intel_txt.txt
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt
iostats.txt block: Track DISCARD statistics and output them in stat and diskstat 2018-07-18 08:44:22 -06:00
IPMI.txt
IRQ-affinity.txt
IRQ-domain.txt
IRQ.txt
irqflags-tracing.txt
isa.txt
isapnp.txt
kernel-per-CPU-kthreads.txt doc: Update removal of RCU-bh/sched update machinery 2018-08-30 10:59:48 -07:00
kobject.txt kref/kobject: Improve documentation 2018-12-06 13:57:03 +01:00
kprobes.txt
kref.txt
ldm.txt
lockup-watchdogs.txt
logo.gif
logo.txt
lsm.txt
lzo.txt lib/lzo: fix bugs for very short or empty input 2019-04-05 16:02:30 -10:00
mailbox.txt
Makefile kbuild: Add support for DT binding schema checks 2018-12-13 09:41:32 -06:00
memory-barriers.txt Documentation: Use "while" instead of "whilst" 2018-11-20 09:30:43 -07:00
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 Documentation: preempt-locking: Use better example 2018-10-12 11:35:47 -06:00
pwm.txt
rbtree.txt
remoteproc.txt
rfkill.txt
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt
rtc.txt
SAK.txt
sgi-ioc4.txt
siphash.txt
SM501.txt
smsc_ece1099.txt
speculation.txt
static-keys.txt static_keys.txt: Fix trivial spelling mistake 2019-02-06 16:44:16 -07:00
SubmittingPatches
svga.txt
switchtec.txt NTB: switchtec_ntb: Update switchtec documentation with prerequisites for NTB 2018-10-11 11:28:53 -05:00
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