linux/Documentation
Peter W Morreale fafd688e4c mm: add /proc controls for pdflush threads
Add /proc entries to give the admin the ability to control the minimum and
maximum number of pdflush threads.  This allows finer control of pdflush
on both large and small machines.

The rationale is simply one size does not fit all.  Admins on large and/or
small systems may want to tune the min/max pdflush thread count to best
suit their needs.  Right now the min/max is hardcoded to 2/8.  While
probably a fair estimate for smaller machines, large machines with large
numbers of CPUs and large numbers of filesystems/block devices may benefit
from larger numbers of threads working on different block devices.

Even if the background flushing algorithm is radically changed, it is
still likely that multiple threads will be involved and admins would still
desire finer control on the min/max other than to have to recompile the
kernel.

The patch adds '/proc/sys/vm/nr_pdflush_threads_min' and
'/proc/sys/vm/nr_pdflush_threads_max' with r/w permissions.

The minimum value for nr_pdflush_threads_min is 1 and the maximum value is
the current value of nr_pdflush_threads_max.  This minimum is required
since additional thread creation is performed in a pdflush thread itself.

The minimum value for nr_pdflush_threads_max is the current value of
nr_pdflush_threads_min and the maximum value can be 1000.

Documentation/sysctl/vm.txt is also updated.

[akpm@linux-foundation.org: fix comment, fix whitespace, use __read_mostly]
Signed-off-by: Peter W Morreale <pmorreale@novell.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:03 -07:00
..
ABI Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-05 11:04:19 -07:00
accounting Documentation/accounting/getdelays.c: fix endless loop 2009-01-15 16:39:37 -08:00
acpi ACPI: update debug parameter documentation 2008-11-07 21:45:29 -05:00
aoe
arm Merge branch 'next-s3c-pm' of git://aeryn.fluff.org.uk/bjdooks/linux into devel 2009-03-26 22:44:43 +00:00
auxdisplay .gitignore updates 2008-10-30 11:38:45 -07:00
blackfin Blackfin arch: Add document about bfin-gpio 2009-01-07 23:14:38 +08:00
block block: Repeated lines in switching-sched.txt 2009-03-26 11:01:28 +01:00
blockdev Create/use more directory structure in the Documentation/ tree. 2008-11-14 17:28:53 +00:00
cdrom doc/cdrom: Trvial documentation error, file not present 2008-10-10 08:22:44 +02:00
cgroups Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-04-03 15:24:35 -07:00
connector Documentation/connector/cn_test.c: don't use gfp_any() 2009-02-12 16:47:01 -08:00
console
cpu-freq [CPUFREQ] ondemand/conservative: sanitize sampling_rate restrictions 2009-02-24 22:47:31 -05:00
cpuidle
cris fix random typos 2008-10-16 11:21:30 -07:00
crypto async_tx, dmaengine: document channel allocation and api rework 2009-01-05 18:10:19 -07:00
development-process Fix a typo in the development process document. 2009-01-08 16:32:13 -07:00
device-mapper dm crypt: add documentation 2008-04-25 13:27:03 +01:00
DocBook docbook: fix fatal filename error 2009-04-06 13:43:42 -07:00
driver-model PATCH [1/2] Documentation/driver-model/device.txt: fix struct device_attribute 2009-02-22 09:27:15 -08:00
dvb V4L/DVB (11138): get_dvb_firmware: add support for downloading the cx2584x firmware for pvrusb2 2009-03-30 12:43:31 -03:00
early-userspace Documentation: Remove last references to BitKeeper. 2008-04-21 22:19:05 +00:00
fault-injection
fb fbdev: remove cyblafb driver 2009-04-01 08:59:33 -07:00
filesystems Merge branch 'for-2.6.30' of git://linux-nfs.org/~bfields/linux 2009-04-06 13:25:56 -07:00
firmware_class firmware_sample_driver.c: fix coding style 2008-04-21 22:23:30 +00:00
frv
hwmon hwmon: Add LTC4215 driver 2009-04-01 08:59:21 -07:00
i2c Move the pcf8591 driver to hwmon 2009-03-30 21:46:43 +02:00
i2o
ia64 trivial: Fix misspelling of firmware 2009-03-30 15:21:59 +02:00
ide ide: update warm-plug HOWTO 2009-01-06 17:21:00 +01:00
infiniband
input Merge commit 'v2.6.28-rc9' into next 2008-12-20 04:54:54 -05:00
ioctl V4L/DVB (10870a): remove all references for video_decoder.h 2009-03-30 12:43:15 -03:00
isdn gigaset: documentation update 2009-04-06 17:07:57 -07:00
ja_JP Sync patch for jp_JP/stable_kernel_rules.txt 2009-01-28 15:55:48 -08:00
kbuild kbuild: fix kbuild.txt typos 2009-01-14 21:42:51 +01:00
kdump powerpc: Support for relocatable kdump kernel 2008-10-22 15:01:22 +11:00
ko_KR
laptops Merge branch 'thinkpad-acpi' into release 2009-04-05 01:42:09 -04:00
lguest lguest: barrier me harder 2009-03-30 21:55:26 +10:30
m68k
make
mips ide: remove unused CONFIG_BLK_DEV_IDE_AU1XXX_SEQTS_PER_RQ 2009-01-14 19:19:03 +01:00
misc-devices drivers/misc/isl29003.c: driver for the ISL29003 ambient light sensor 2009-04-01 08:59:18 -07:00
mn10300
mtd [MTD] [NAND] nand_ecc.c: rewrite for improved performance 2008-08-16 10:55:33 +01:00
namespaces
netlabel
networking Neterion: Driver help file 2009-04-02 00:33:39 -07:00
parisc
PCI PCI MSI: Add example request loop to MSI-HOWTO.txt 2009-03-20 11:35:04 -07:00
pcmcia .gitignore updates 2008-10-30 11:38:45 -07:00
power pm: document use of RTC in pm_trace 2008-10-16 11:21:29 -07:00
powerpc Merge git://git.infradead.org/mtd-2.6 2009-04-06 14:56:26 -07:00
prctl generic, x86: add tests for prctl PR_GET_TSC and PR_SET_TSC 2008-04-19 19:19:55 +02:00
RCU Doc: Fix spelling in RCU/rculist_nulls.txt. 2009-04-02 01:33:51 -07:00
s390 documentation: update s390 header file paths 2009-01-06 15:59:28 -08:00
scheduler trivial: fix where cgroup documentation is not correctly referred to 2009-03-30 15:22:02 +02:00
scsi [SCSI] aacraid driver update 2009-04-03 09:23:11 -05:00
serial Create/use more directory structure in the Documentation/ tree. 2008-11-14 17:28:53 +00:00
sh sh: Kill off remaining CONFIG_SH_KGDB bits. 2008-12-22 18:44:05 +09:00
sound Merge branch 'topic/oxygen' into for-linus 2009-03-24 00:36:17 +01:00
sparc sparc: Remove Documentation/sparc/sbus_drivers.txt 2008-08-29 02:15:25 -07:00
spi hwmon: (lm70) Code streamlining and cleanup 2009-01-07 16:37:34 +01:00
sysctl mm: add /proc controls for pdflush threads 2009-04-07 08:31:03 -07:00
telephony remove mention of CONFIG_KMOD from documentation 2008-07-22 19:24:29 +10:00
thermal thermal: update the documentation 2008-04-29 02:49:47 -04:00
timers hpet: /dev/hpet - fixes and cleanup 2008-07-31 18:45:41 +02:00
tracers doc: mmiotrace.txt, buffer size control change 2009-02-15 20:05:13 +01:00
uml
usb USB: usbmon: Add binary API v1 2009-03-24 16:20:36 -07:00
video4linux V4L/DVB (11373): v4l2-common: add explicit v4l2_device pointer as first arg to new_(probed)_subdev 2009-04-06 21:44:24 -03:00
vm Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-05 11:04:19 -07:00
w1 w1: send status messages after command processing 2009-01-08 08:31:14 -08:00
watchdog .gitignore updates 2008-10-30 11:38:45 -07:00
wimax i2400m: documentation and instructions for usage 2009-01-07 10:00:18 -08:00
x86 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-04-03 15:24:35 -07:00
zh_CN
00-INDEX trivial: fix where cgroup documentation is not correctly referred to 2009-03-30 15:22:02 +02:00
applying-patches.txt
atomic_ops.txt
bad_memory.txt Document handling of bad memory 2008-12-03 16:09:53 -07:00
basic_profiling.txt
binfmt_misc.txt
braille-console.txt Basic braille screen reader support 2008-04-30 08:29:52 -07:00
bt8xxgpio.txt gpio: add bt8xxgpio driver 2008-07-25 10:53:30 -07:00
BUG-HUNTING
c2port.txt Add c2 port support 2008-11-12 17:17:18 -08:00
cachetlb.txt
Changes Documentation/Changes: add required versions for new filesystems 2009-01-29 18:19:30 -08:00
CodingStyle fix emacs indenting howto filename expansion 2009-01-29 18:19:29 -08:00
cpu-hotplug.txt x86: use possible_cpus=NUM to extend the possible cpus allowed 2008-12-18 12:08:05 +01:00
cpu-load.txt
cputopology.txt cpumask: Use topology_core_cpumask()/topology_thread_cpumask() 2009-01-11 19:12:49 +01:00
credentials.txt CRED: Documentation 2008-11-14 10:39:26 +11:00
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt firewire: fw-ohci: add option for remote debugging 2008-04-18 17:55:33 +02:00
dell_rbu.txt trivial: fix an -> a typos in documentation and comments 2009-01-06 11:28:07 +01:00
devices.txt LANANA: Fix dates 2009-04-06 14:54:17 -07:00
DMA-API.txt dma-debug: Documentation update 2009-03-17 12:56:47 +01:00
DMA-attributes.txt powerpc/cell: Add DMA_ATTR_WEAK_ORDERING dma attribute and use in Cell IOMMU code 2008-07-22 10:39:36 +10:00
DMA-ISA-LPC.txt
DMA-mapping.txt documentation: update header file paths 2009-01-06 15:59:28 -08:00
dmaengine.txt async_tx, dmaengine: document channel allocation and api rework 2009-01-05 18:10:19 -07:00
dontdiff dontdiff: Fix asm exclude 2009-03-26 15:45:43 -07:00
dynamic-debug-howto.txt Dynamic debug: allow simple quoting of words 2009-03-24 16:38:27 -07:00
edac.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
eisa.txt
email-clients.txt Documentation/email-clients.txt: add some info about gmail 2008-11-06 15:41:19 -08:00
exception.txt
feature-removal-schedule.txt i2c: Deprecate client_register and client_unregister methods 2009-04-06 18:12:24 +02:00
ftrace.txt ftrace: fix documentation typo s/trace_max_latency/tracing_max_latency/ 2009-03-08 16:50:07 +01:00
gpio.txt gpio: gpio_{request,free}() now required (feature removal) 2009-04-02 19:04:51 -07:00
highuid.txt [SPARC]: Remove SunOS and Solaris binary support. 2008-04-21 15:10:15 -07:00
HOWTO Remove Andrew Morton's http://www.zip.com.au/~akpm/ 2008-10-16 11:21:32 -07:00
hw_random.txt hw_random doc updates 2008-03-24 19:22:19 -07:00
ics932s401 ics932s401: new clock generator chip driver 2008-11-12 17:17:18 -08:00
initrd.txt
Intel-IOMMU.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
IO-mapping.txt Documentation: move DMA-mapping.txt to Doc/PCI/ 2009-01-29 18:19:29 -08:00
io-mapping.txt io mapping: improve documentation 2008-11-03 18:21:44 +01:00
io_ordering.txt
iostats.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
IPMI.txt
IRQ-affinity.txt genirq: Expose default irq affinity mask (take 3) 2008-06-05 15:18:30 +02:00
IRQ.txt
irqflags-tracing.txt
isapnp.txt
java.txt
kernel-doc-nano-HOWTO.txt kernel-doc: preferred ending marker and examples 2009-02-11 14:25:36 -08:00
kernel-docs.txt doc: update to URL and status of kernel-docs.txt entry 2008-06-06 11:29:10 -07:00
kernel-parameters.txt docs: alphabetize entries in kernel-parameters.txt 2009-04-06 13:43:43 -07:00
keys-request-key.txt keys: allow the callout data to be passed as a blob rather than a string 2008-04-29 08:06:16 -07:00
keys.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
kobject.txt kobject: Make Documentation/kobject.txt a little more coherent. 2009-01-06 10:44:32 -08:00
kprobes.txt kprobes: support probing module __exit function 2009-01-06 15:59:21 -08:00
kref.txt
ldm.txt
leds-class.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
local_ops.txt documentation: local_ops fix on_each_cpu 2008-12-01 13:51:26 +01:00
lockdep-design.txt lockdep: get_user_chars() redo 2009-02-14 23:28:22 +01:00
lockstat.txt lockstat: contend with points 2008-10-20 15:43:10 +02:00
logo.svg linux.conf.au 2009: Tuz 2009-03-16 07:55:37 -07:00
logo.txt linux.conf.au 2009: Tuz 2009-03-16 07:55:37 -07:00
magic-number.txt documentation: update header file paths 2009-01-06 15:59:28 -08:00
Makefile docsrc: build Documentation/ sources 2008-08-12 16:07:30 -07:00
ManagementStyle docs: fix ManagementStyle book name 2008-10-30 11:38:46 -07:00
markers.txt markers: comment marker_synchronize_unregister() on data dependency 2008-11-28 16:47:41 +01:00
mca.txt The ps2esdi driver was marked as BROKEN more than two years ago due to being 2008-03-17 09:03:05 +01:00
md.txt Documentation/md.txt update 2009-03-31 15:18:37 +11:00
memory-barriers.txt read_barrier_depends arch fixlets 2008-05-14 10:05:18 -07:00
memory-hotplug.txt mm: show node to memory section relationship with symlinks in sysfs 2009-01-06 15:59:00 -08:00
memory.txt
mono.txt
mutex-design.txt
nmi_watchdog.txt x86, nmi-watchdog: update procfs nmi_watchdog file documentation v2 2008-10-30 19:07:04 +01:00
nommu-mmap.txt NOMMU: Make mmap allocation page trimming behaviour configurable. 2009-01-08 12:04:47 +00:00
numastat.txt
oops-tracing.txt Taint kernel after WARN_ON(condition) 2008-04-29 08:05:59 -07:00
parport-lowlevel.txt
parport.txt
pi-futex.txt
pnp.txt
preempt-locking.txt
printk-formats.txt DOC: add printk-formats.txt 2008-11-12 17:17:17 -08:00
prio_tree.txt
rbtree.txt
rfkill.txt rfkill: add master_switch_mode and EPO lock to rfkill and rfkill-input 2008-10-31 19:00:09 -04:00
robust-futex-ABI.txt
robust-futexes.txt
rt-mutex-design.txt
rt-mutex.txt
rtc.txt
SAK.txt Remove Andrew Morton's old email accounts 2008-10-16 11:21:32 -07:00
SecurityBugs
SELinux.txt selinux: add support for installing a dummy policy (v2) 2008-08-27 08:54:08 +10:00
serial-console.txt
sgi-ioc4.txt
sgi-visws.txt
slow-work.txt Document the slow work thread pool 2009-04-03 16:42:35 +01:00
SM501.txt
Smack.txt smack: Add a new '-CIPSO' option to the network address label configuration 2009-03-28 15:01:37 +11:00
sparse.txt kbuild: sparse needs CF not CHECKFLAGS 2008-07-25 22:12:39 +02:00
spinlocks.txt Add additional examples in Documentation/spinlocks.txt 2008-04-11 13:21:14 -06:00
stable_api_nonsense.txt
stable_kernel_rules.txt Update stable tree documentation 2008-10-29 15:03:49 -07:00
SubmitChecklist documentation: explain memory barriers 2008-10-16 11:21:32 -07:00
SubmittingDrivers Remove Andrew Morton's old email accounts 2008-10-16 11:21:32 -07:00
SubmittingPatches Merge branch 'docs' of git://git.lwn.net/linux-2.6 2008-10-16 12:18:16 -07:00
svga.txt
sysfs-rules.txt sysfs-rules.txt: reword API stability statement 2008-07-21 21:54:59 -07:00
sysrq.txt Merge branch 'tracing/core-v2' into tracing-for-linus 2009-04-02 00:49:02 +02:00
tracepoints.txt tracing: Documentation / sample code fixes for tracepoints 2009-03-24 22:32:12 +01:00
unaligned-memory-access.txt introduce HAVE_EFFICIENT_UNALIGNED_ACCESS Kconfig symbol 2008-07-25 10:53:27 -07:00
unicode.txt
unshare.txt
VGA-softcursor.txt
video-output.txt
volatile-considered-harmful.txt Documentation cleanup: trivial misspelling, punctuation, and grammar corrections. 2008-07-26 12:00:06 -07:00
voyager.txt
zorro.txt