linux/kernel
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
..
irq Merge branch 'tracing/core-v2' into tracing-for-linus 2009-04-02 00:49:02 +02:00
power Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-04-03 15:24:35 -07:00
time Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-03-26 16:05:42 -07:00
trace Merge branch 'kmemtrace-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-06 13:30:00 -07:00
.gitignore
acct.c [CVE-2009-0029] System call wrappers part 04 2009-01-14 14:15:19 +01:00
async.c async: remove the temporary (2.6.29) "async is off by default" code 2009-03-28 13:05:30 -07:00
audit_tree.c audit: incorrect ref counting in audit tree tag_chunk 2009-04-05 13:48:26 -04:00
audit.c Audit: remove spaces from audit_log_d_path 2009-04-05 13:49:04 -04:00
audit.h fixing audit rule ordering mess, part 1 2009-01-04 15:14:41 -05:00
auditfilter.c make the e->rule.xxx shorter in kernel auditfilter.c 2009-04-05 13:40:33 -04:00
auditsc.c Audit: remove spaces from audit_log_d_path 2009-04-05 13:49:04 -04:00
backtracetest.c
bounds.c
capability.c [CVE-2009-0029] System call wrappers part 04 2009-01-14 14:15:19 +01:00
cgroup_debug.c debug cgroup: remove unneeded cgroup_lock 2009-04-02 19:04:54 -07:00
cgroup_freezer.c freezer_cg: disable writing freezer.state of root cgroup 2008-11-12 17:17:16 -08:00
cgroup.c memcg: fix OOM killer under memcg 2009-04-02 19:04:55 -07:00
compat.c Allow times and time system calls to return small negative values 2009-01-06 15:59:13 -08:00
configs.c kernel/configs.c: remove useless comments 2008-10-20 08:52:34 -07:00
cpu.c cpumask: use set_cpu_active in init/main.c 2009-03-30 22:05:12 +10:30
cpuset.c cpusets: prevent PF_THREAD_BOUND tasks from attaching to non-root cpusets 2009-04-02 19:04:57 -07:00
cred-internals.h CRED: Inaugurate COW credentials 2008-11-14 10:39:23 +11:00
cred.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6 2009-01-09 13:59:25 -08:00
delayacct.c schedstat: consolidate per-task cpu runtime stats 2008-12-18 13:54:01 +01:00
dma-coherent.c dma-coherent: Restore dma_alloc_from_coherent() large alloc fall back policy. 2009-01-21 18:51:53 +09:00
dma.c kernel/dma.c: remove a CVS keyword 2008-10-16 11:21:30 -07:00
exec_domain.c Get rid of indirect include of fs_struct.h 2009-03-31 23:00:27 -04:00
exit.c exit_notify: kill the wrong capable(CAP_KILL) check 2009-04-06 14:57:23 -07:00
extable.c 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
fork.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-04-02 21:09:10 -07:00
freezer.c freezer_cg: use thaw_process() in unfreeze_cgroup() 2008-10-30 11:38:45 -07:00
futex_compat.c CRED: Use RCU to access another task's creds and to release a task's own creds 2008-11-14 10:39:19 +11:00
futex.c futex: remove the pointer math from double_unlock_hb, fix 2009-03-13 10:32:07 +01:00
hrtimer.c hrtimer: fix rq->lock inversion (again) 2009-03-31 14:52:52 +02:00
itimer.c timers: split process wide cpu clocks/timers 2009-02-05 13:04:33 +01:00
kallsyms.c Ksplice: Add functions for walking kallsyms symbols 2009-03-31 13:05:32 +10:30
Kconfig.freezer container freezer: implement freezer cgroup subsystem 2008-10-20 08:52:34 -07:00
Kconfig.hz
Kconfig.preempt rcu: provide RCU options on non-preempt architectures too 2008-12-25 09:31:28 +01:00
kexec.c kexec: vmcoreinfo_data[] can become static 2009-04-02 19:05:04 -07:00
kfifo.c
kgdb.c kgdb: call touch_softlockup_watchdog on resume 2008-10-06 13:50:59 -05:00
kmod.c module: create a request_module_nowait() 2009-03-31 13:05:35 +10:30
kprobes.c kprobes: Fix locking imbalance in kretprobes 2009-03-18 12:51:16 +01:00
ksysfs.c kernel/ksysfs.c:fix dependence on CONFIG_NET 2009-01-06 10:44:31 -08:00
kthread.c cpumask: remove dangerous CPU_MASK_ALL_PTR, &CPU_MASK_ALL 2009-03-30 22:05:11 +10:30
latencytop.c sched, latencytop: incorporate review feedback from Andrew Morton 2009-02-11 10:18:04 +01:00
lockdep_internals.h lockdep: get_user_chars() redo 2009-02-14 23:28:22 +01:00
lockdep_proc.c lockstat: warn about disabled lock debugging 2009-02-14 23:28:28 +01:00
lockdep_states.h lockdep: move state bit definitions around 2009-02-14 23:27:59 +01:00
lockdep.c Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-06 13:37:30 -07:00
Makefile Create a dynamically sized pool of threads for doing very slow work items 2009-04-03 16:42:35 +01:00
marker.c markers/tracpoints: fix non-modular build 2008-11-16 09:52:03 +01:00
module.c Revert "module: remove the SHF_ALLOC flag on the __versions section." 2009-04-07 17:12:43 +09:30
mutex-debug.c mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
mutex-debug.h mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
mutex.c mutex: adaptive spinnning, performance tweaks 2009-01-14 19:03:54 +01:00
mutex.h mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
notifier.c Merge commit 'v2.6.28-rc6' into core/debug 2008-11-26 08:22:50 +01:00
ns_cgroup.c cgroups: relax ns_can_attach checks to allow attaching to grandchild cgroups 2009-04-02 19:04:53 -07:00
nsproxy.c User namespaces: set of cleanups (v2) 2008-11-24 18:57:41 -05:00
panic.c panic: clean up kernel/panic.c 2009-03-13 11:25:53 +01:00
params.c param: fix charp parameters set via sysfs 2009-03-31 13:05:30 +10:30
pid_namespace.c signals: zap_pid_ns_process() should use force_sig() 2009-04-02 19:04:58 -07:00
pid.c pids: refactor vnr/nr_ns helpers to make them safe 2009-04-02 19:05:02 -07:00
pm_qos_params.c
posix-cpu-timers.c posix timers: fix RLIMIT_CPU && fork() 2009-03-23 20:43:35 +01:00
posix-timers.c [CVE-2009-0029] System call wrappers part 05 2009-01-14 14:15:20 +01:00
printk.c Merge branch 'printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-05 10:23:25 -07:00
profile.c profiling: fix broken profiling regression 2009-02-10 00:50:37 +01:00
ptrace.c Merge branch 'core-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-03 17:35:06 -07:00
rcuclassic.c kmemtrace, rcu: fix linux/rcutree.h and linux/rcuclassic.h dependencies 2009-04-03 12:23:02 +02:00
rcupdate.c rcu: rcu_barrier VS cpu_hotplug: Ensure callbacks in dead cpu are migrated to online cpu 2009-03-31 00:09:37 +02:00
rcupreempt_trace.c "Tree RCU": scalable classic RCU implementation 2008-12-18 21:56:04 +01:00
rcupreempt.c kmemtrace, rcu: fix rcupreempt.c data structure dependencies 2009-04-03 12:23:04 +02:00
rcutorture.c cpumask: convert rcutorture.c 2009-03-30 22:05:16 +10:30
rcutree_trace.c kmemtrace, rcu: fix rcu_tree_trace.c data structure dependencies 2009-04-03 12:23:03 +02:00
rcutree.c kmemtrace, rcu: fix rcu_tree_trace.c data structure dependencies 2009-04-03 12:23:03 +02:00
rcutree.h kmemtrace, rcu: fix rcu_tree_trace.c data structure dependencies 2009-04-03 12:23:03 +02:00
relay.c 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
res_counter.c memcg: memory cgroup resource counters for hierarchy 2009-01-08 08:31:05 -08:00
resource.c resources: fix parameter name and kernel-doc 2009-01-15 16:39:38 -08:00
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutex.h
rwsem.c
sched_clock.c Merge branch 'tracing/core-v2' into tracing-for-linus 2009-04-02 00:49:02 +02:00
sched_cpupri.c sched: fix section mismatch 2009-01-06 11:07:15 +01:00
sched_cpupri.h cpumask: remove cpumask_t from core 2009-03-30 22:05:17 +10:30
sched_debug.c sched: remove unused fields from struct rq 2009-03-24 23:16:51 +01:00
sched_fair.c Merge branch 'sched/urgent'; commit 'v2.6.29-rc5' into sched/core 2009-02-15 21:15:16 +01:00
sched_features.h Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-03-30 17:17:35 -07:00
sched_idletask.c sched: add CONFIG_SMP consistency 2008-10-22 10:01:52 +02:00
sched_rt.c Merge branch 'core/percpu' into percpu-cpumask-x86-for-linus-2 2009-03-27 17:28:43 +01:00
sched_stats.h sched: remove unused fields from struct rq 2009-03-24 23:16:51 +01:00
sched.c Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-06 13:37:30 -07:00
seccomp.c x86-64: seccomp: fix 32/64 syscall hole 2009-03-02 15:41:30 -08:00
semaphore.c
signal.c signals: SI_USER: Masquerade si_pid when crossing pid ns boundary 2009-04-02 19:04:58 -07:00
slow-work.c Document the slow work thread pool 2009-04-03 16:42:35 +01:00
smp.c generic-ipi: eliminate WARN_ON()s during oops/panic 2009-03-13 10:47:34 +01:00
softirq.c Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-06 13:37:30 -07:00
softlockup.c softlock: fix false panic which can occur if softlockup_thresh is reduced 2009-01-14 11:48:07 +01:00
spinlock.c Allow rwlocks to re-enable interrupts 2009-04-02 19:05:11 -07:00
srcu.c
stacktrace.c stacktrace: provide save_stack_trace_tsk() weak alias 2008-12-25 11:44:43 +01:00
stop_machine.c cpumask: remove cpumask_t from core 2009-03-30 22:05:17 +10:30
sys_ni.c [CVE-2009-0029] Make sys_syslog a conditional system call 2009-01-14 14:15:16 +01:00
sys.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2009-04-02 21:09:10 -07:00
sysctl_check.c net: add ARP notify option for devices 2009-02-01 01:04:33 -08:00
sysctl.c mm: add /proc controls for pdflush threads 2009-04-07 08:31:03 -07:00
taskstats.c cpumask: convert rest of files in kernel/ 2009-01-01 10:12:28 +10:30
test_kprobes.c kprobes: add tests for register_kprobes 2009-01-06 15:59:20 -08:00
time.c [CVE-2009-0029] System call wrappers part 01 2009-01-14 14:15:18 +01:00
timeconst.pl
timer.c Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-03-30 17:17:35 -07:00
tracepoint.c tracepoints: dont update zero-sized tracepoint sections 2009-03-18 19:55:00 +01:00
tsacct.c Fix fixpoint divide exception in acct_update_integrals 2009-03-09 08:13:35 -07:00
uid16.c [CVE-2009-0029] System call wrappers part 19 2009-01-14 14:15:26 +01:00
up.c smp_call_function_single(): be slightly less stupid, fix #2 2009-01-12 16:04:37 +01:00
user_namespace.c Fix recursive lock in free_uid()/free_user_ns() 2009-02-27 16:26:21 -08:00
user.c Merge branch 'master' into next 2009-03-24 10:52:46 +11:00
utsname_sysctl.c proc_sysctl: use CONFIG_PROC_SYSCTL around ipc and utsname proc_handlers 2009-04-02 19:05:01 -07:00
utsname.c
wait.c wait: prevent exclusive waiter starvation 2009-02-05 12:56:48 -08:00
workqueue.c 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