Miklos Szeredi 53da1d9456 fix ptrace slowness ... This patch fixes bug #12208: Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=12208 Subject : uml is very slow on 2.6.28 host This turned out to be not a scheduler regression, but an already existing problem in ptrace being triggered by subtle scheduler changes. The problem is this: - task A is ptracing task B - task B stops on a trace event - task A is woken up and preempts task B - task A calls ptrace on task B, which does ptrace_check_attach() - this calls wait_task_inactive(), which sees that task B is still on the runq - task A goes to sleep for a jiffy - ... Since UML does lots of the above sequences, those jiffies quickly add up to make it slow as hell. This patch solves this by not rescheduling in read_unlock() after ptrace_stop() has woken up the tracer. Thanks to Oleg Nesterov and Ingo Molnar for the feedback. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> CC: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2009-03-23 09:22:31 -07:00
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irq
power	PM: Split up sysdev_[suspend|resume] from device_power_[down|up]	2009-02-22 10:33:44 -08:00
time
trace	tracing: limit the number of loops the ring buffer self test can make	2009-02-18 22:50:01 -05:00
.gitignore
acct.c
async.c	async: use list_move_tail	2009-02-08 10:00:26 -08:00
audit.c
audit.h
audit_tree.c
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
cgroup.c	cgroups: fix possible use after free	2009-02-18 15:37:54 -08:00
cgroup_debug.c
cgroup_freezer.c
compat.c
configs.c
cpu.c
cpuset.c
cred-internals.h
cred.c
delayacct.c
dma-coherent.c
dma.c
exec_domain.c
exit.c
extable.c
fork.c	copy_process: fix CLONE_PARENT && parent_exec_id interaction	2009-03-09 13:23:25 -07:00
freezer.c
futex.c	futex: fix reference leak	2009-02-11 18:24:08 +01:00
futex_compat.c
hrtimer.c
itimer.c
kallsyms.c
Kconfig.freezer
Kconfig.hz
Kconfig.preempt
kexec.c	PM: Split up sysdev_[suspend|resume] from device_power_[down|up]	2009-02-22 10:33:44 -08:00
kfifo.c
kgdb.c
kmod.c
kprobes.c
ksysfs.c
kthread.c
latencytop.c
lockdep.c
lockdep_internals.h
lockdep_proc.c
Makefile	PM: fix build for CONFIG_PM unset	2009-02-21 14:17:17 -08:00
marker.c
module.c	module: fix refptr allocation and release order	2009-03-18 09:31:21 +10:30
mutex-debug.c
mutex-debug.h
mutex.c
mutex.h
notifier.c
ns_cgroup.c
nsproxy.c
panic.c
params.c
pid.c
pid_namespace.c
pm_qos_params.c
posix-cpu-timers.c	timers: more consistently use clock vs timer	2009-02-13 13:04:05 +01:00
posix-timers.c
printk.c	PM: Fix suspend_console and resume_console to use only one semaphore	2009-02-21 14:17:18 -08:00
profile.c	profiling: fix broken profiling regression	2009-02-10 00:50:37 +01:00
ptrace.c
rcuclassic.c	rcu: Teach RCU that idle task is not quiscent state at boot	2009-02-26 04:08:14 +01:00
rcupdate.c	rcu: Teach RCU that idle task is not quiscent state at boot	2009-02-26 04:08:14 +01:00
rcupreempt.c	rcu: Teach RCU that idle task is not quiscent state at boot	2009-02-26 04:08:14 +01:00
rcupreempt_trace.c
rcutorture.c
rcutree.c	rcu: Teach RCU that idle task is not quiscent state at boot	2009-02-26 04:08:14 +01:00
rcutree_trace.c
relay.c
res_counter.c
resource.c
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutex.h
rtmutex_common.h
rwsem.c
sched.c	sched: don't allow setuid to succeed if the user does not have rt bandwidth	2009-02-27 11:11:53 +01:00
sched_clock.c
sched_cpupri.c
sched_cpupri.h
sched_debug.c
sched_fair.c	sched: revert recent sync wakeup changes	2009-02-11 14:43:35 +01:00
sched_features.h
sched_idletask.c
sched_rt.c
sched_stats.h
seccomp.c	x86-64: seccomp: fix 32/64 syscall hole	2009-03-02 15:41:30 -08:00
semaphore.c
signal.c	fix ptrace slowness	2009-03-23 09:22:31 -07:00
smp.c
softirq.c	rcu: increment quiescent state counter in ksoftirqd()	2009-03-04 22:08:45 +01:00
softlockup.c
spinlock.c
srcu.c
stacktrace.c
stop_machine.c
sys.c	sched: don't allow setuid to succeed if the user does not have rt bandwidth	2009-02-27 11:11:53 +01:00
sys_ni.c
sysctl.c	mm: fix dirty_bytes/dirty_background_bytes sysctls on 64bit arches	2009-02-11 14:25:35 -08:00
sysctl_check.c
taskstats.c
test_kprobes.c
time.c
timeconst.pl
timer.c
tracepoint.c
tsacct.c	Fix fixpoint divide exception in acct_update_integrals	2009-03-09 08:13:35 -07:00
uid16.c
up.c
user.c	kernel/user.c: fix a memory leak when freeing up non-init usernamespaces users	2009-03-10 15:55:11 -07:00
user_namespace.c	Fix recursive lock in free_uid()/free_user_ns()	2009-02-27 16:26:21 -08:00
utsname.c
utsname_sysctl.c
wait.c	wait: prevent exclusive waiter starvation	2009-02-05 12:56:48 -08:00
workqueue.c