linux_dsm_epyc7002/drivers
Minchan Kim bb416d18b8 zram: writeback throttle
If there are lots of write IO with flash device, it could have a
wearout problem of storage. To overcome the problem, admin needs
to design write limitation to guarantee flash health
for entire product life.

This patch creates a new knob "writeback_limit" for zram.

writeback_limit's default value is 0 so that it doesn't limit
any writeback. If admin want to measure writeback count in a
certain period, he could know it via /sys/block/zram0/bd_stat's
3rd column.

If admin want to limit writeback as per-day 400M, he could do it
like below.

	MB_SHIFT=20
	4K_SHIFT=12
	echo $((400<<MB_SHIFT>>4K_SHIFT)) > \
		/sys/block/zram0/writeback_limit.

If admin want to allow further write again, he could do it like below

	echo 0 > /sys/block/zram0/writeback_limit

If admin want to see remaining writeback budget,

	cat /sys/block/zram0/writeback_limit

The writeback_limit count will reset whenever you reset zram (e.g., system
reboot, echo 1 > /sys/block/zramX/reset) so keeping how many of writeback
happened until you reset the zram to allocate extra writeback budget in
next setting is user's job.

[minchan@kernel.org: v4]
  Link: http://lkml.kernel.org/r/20181203024045.153534-8-minchan@kernel.org
Link: http://lkml.kernel.org/r/20181127055429.251614-8-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Joey Pabalinas <joeypabalinas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:49 -08:00
..
accessibility
acpi pstore improvements and refactorings 2018-12-27 11:15:21 -08:00
amba
android
ata
atm
auxdisplay
base drivers/base/memory.c: remove an unnecessary check on NR_MEM_SECTIONS 2018-12-28 12:11:48 -08:00
bcma
block zram: writeback throttle 2018-12-28 12:11:49 -08:00
bluetooth
bus
cdrom
char mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
clk
clocksource Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-12-25 15:44:08 -08:00
connector
cpufreq powerpc updates for 4.21 2018-12-27 10:43:24 -08:00
cpuidle powerpc updates for 4.21 2018-12-27 10:43:24 -08:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-12-27 13:53:32 -08:00
dax mm, devm_memremap_pages: fix shutdown handling 2018-12-28 12:11:47 -08:00
dca
devfreq
dio
dma
dma-buf
edac
eisa
extcon
firewire
firmware pstore improvements and refactorings 2018-12-27 11:15:21 -08:00
fmc
fpga
fsi
gnss
gpio regmap: Updates for v4.21 2018-12-25 14:48:06 -08:00
gpu mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
hid
hsi
hv mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
hwmon Merge branch 'x86-amd-nb-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-12-26 16:12:50 -08:00
hwspinlock
hwtracing
i2c platform-drivers-x86 for v4.21-1 2018-12-25 11:04:17 -08:00
i3c
ide powerpc updates for 4.21 2018-12-27 10:43:24 -08:00
idle
iio platform-drivers-x86 for v4.21-1 2018-12-25 11:04:17 -08:00
infiniband
input Merge branch 'parisc-4.21-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux 2018-12-26 11:14:52 -08:00
iommu
ipack
irqchip
isdn
leds LEDs for 4.21-rc1 2018-12-25 14:52:50 -08:00
lightnvm
macintosh macintosh: Use of_node_name_{eq, prefix} for node name comparisons 2018-12-22 21:29:56 +11:00
mailbox
mcb
md mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
media mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
memory
memstick
message
mfd
misc mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
mmc
mtd spi: Updates for v4.21 2018-12-25 14:43:54 -08:00
mux
net Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-12-27 13:53:32 -08:00
nfc
ntb
nubus
nvdimm mm, devm_memremap_pages: fix shutdown handling 2018-12-28 12:11:47 -08:00
nvme
nvmem
of Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-12-27 13:04:52 -08:00
opp
oprofile
parisc mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
parport
pci mm, hmm: mark hmm_devmem_{add, add_resource} EXPORT_SYMBOL_GPL 2018-12-28 12:11:48 -08:00
pcmcia
perf
phy
pinctrl
platform Here's the main MIPS pull for Linux 4.21. Core architecture changes 2018-12-26 10:45:33 -08:00
pnp
power
powercap
pps
ps3
ptp
pwm pwm: imx: Add ipg clock operation 2018-12-24 12:06:56 +01:00
rapidio
ras
regulator
remoteproc
reset
rpmsg
rtc
s390
sbus Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next 2018-12-26 10:32:18 -08:00
scsi Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-12-27 13:04:52 -08:00
sfi
sh
siox
slimbus
sn
soc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-12-27 13:04:52 -08:00
soundwire
spi spi: Updates for v4.21 2018-12-25 14:43:54 -08:00
spmi
ssb
staging mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
target Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-12-27 13:04:52 -08:00
tc
tee
thermal
thunderbolt
tty audit/stable-4.21 PR 20181224 2018-12-27 11:58:50 -08:00
uio
usb Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-12-27 13:53:32 -08:00
uwb
vfio
vhost Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-12-27 13:04:52 -08:00
video drm pull request for 4.21-rc1 2018-12-25 11:48:26 -08:00
virt
virtio
visorbus
vlynq
vme
w1
watchdog
xen mm/memory_hotplug: drop "online" parameter from add_memory_resource() 2018-12-28 12:11:48 -08:00
zorro
Kconfig
Makefile