linux/include
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
..
acpi ACPI: support acpi_device_ops .notify methods 2009-04-05 02:25:07 -04:00
asm-arm
asm-frv Merge branch 'tracing/core-v2' into tracing-for-linus 2009-04-02 00:49:02 +02:00
asm-generic 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
asm-h8300
asm-m32r 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
asm-mn10300 Merge branch 'tracing/core-v2' into tracing-for-linus 2009-04-02 00:49:02 +02:00
crypto
drm drm: remove unused "can_grow" parameter from drm_crtc_helper_initial_config 2009-04-03 10:21:44 +10:00
keys
linux mm: add /proc controls for pdflush threads 2009-04-07 08:31:03 -07:00
math-emu
media V4L/DVB (11381): ivtv/cx18: remove VIDIOC_INT_S_AUDIO_ROUTING debug support. 2009-04-06 21:44:28 -03:00
mtd make MTD headers use strict integer types 2009-03-26 18:14:17 +01:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6 2009-04-02 21:05:30 -07:00
pcmcia
rdma Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6 2009-03-26 15:54:36 -07:00
rxrpc
scsi [SCSI] fcoe, libfcoe: Add support for FIP. FCoE discovery and keep-alive. 2009-04-03 09:23:08 -05:00
sound V4L/DVB (10771): tea575x-tuner: convert it to V4L2 API 2009-03-30 12:43:02 -03:00
trace kmemtrace: use tracepoints 2009-04-03 12:23:06 +02:00
video fbdev: update s1d13xxxfb to differ between revisions and production ids 2009-04-01 08:59:32 -07:00
xen
Kbuild