Christian Borntraeger
3401a61e16
stop_machine: make stop_machine_run more virtualization friendly ...
On kvm I have seen some rare hangs in stop_machine when I used more guest
cpus than hosts cpus. e.g. 32 guest cpus on 1 host cpu triggered the
hang quite often. I could also reproduce the problem on a 4 way z/VM host with
a 64 way guest.
It turned out that the guest was consuming all available cpus mostly for
spinning on scheduler locks like rq->lock. This is expected as the threads are
calling yield all the time.
The problem is now, that the host scheduling decisings together with the guest
scheduling decisions and spinlocks not being fair managed to create an
interesting scenario similar to a live lock. (Sometimes the hang resolved
itself after some minutes)
Changing stop_machine to yield the cpu to the hypervisor when yielding inside
the guest fixed the problem for me. While I am not completely happy with this
patch, I think it causes no harm and it really improves the situation for me.
I used cpu_relax for yielding to the hypervisor, does that work on all
architectures?
p.s.: If you want to reproduce the problem, cpu hotplug and kprobes use
stop_machine_run and both triggered the problem after some retries.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
CC: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-05-23 13:09:34 +10:00
genirq: reenable a nobody cared disabled irq when a new driver arrives
2008-05-02 13:40:34 +02:00
Merge branches 'release', 'acpica', 'bugzilla-10224', 'bugzilla-9772', 'bugzilla-9916', 'ec', 'eeepc', 'idle', 'misc', 'pm-legacy', 'sysfs-links-2.6.26', 'thermal', 'thinkpad' and 'video' into release
2008-04-30 13:58:00 -04:00
clocksource: allow read access to available/current_clocksource
2008-05-03 18:11:48 +02:00
Update kernel/.gitignore with new auto-generated files
2008-02-09 23:27:01 -08:00
bsd_acct: using task_struct->tgid is not right in pid-namespaces
2008-03-24 19:22:20 -07:00
[patch 1/1] audit_send_reply(): fix error-path memory leak
2008-05-17 03:30:22 -04:00
[PATCH 1/2] audit: move extern declarations to audit.h
2008-04-28 06:28:04 -04:00
[PATCH] list_for_each_rcu must die: audit
2008-05-17 03:30:23 -04:00
Merge branch 'audit.b50' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current
2008-04-29 11:41:22 -07:00
[PATCH] new predicate - AUDIT_FILETYPE
2008-04-28 06:28:37 -04:00
x86: add a simple backtrace test module
2008-01-30 13:33:08 +01:00
Add kbuild.h that contains common definitions for kbuild users
2008-04-29 08:06:29 -07:00
Add 64-bit capability support to the kernel
2008-02-05 09:44:20 -08:00
mm: bdi: add separate writeback accounting capability
2008-04-30 08:29:50 -07:00
CGroup API files: move "releasable" to cgroup_debug subsystem
2008-04-29 08:06:09 -07:00
ntp: support for TAI
2008-05-01 08:03:59 -07:00
kernel: use non-racy method for proc entries creation
2008-04-29 08:06:22 -07:00
kernel: replace remaining __FUNCTION__ occurrences
2008-04-30 08:29:54 -07:00
Fix cpuset sched_relax_domain_level control file
2008-05-08 10:46:56 -07:00
Add scaled time to taskstats based process accounting
2007-10-18 14:37:28 -07:00
kernel: use non-racy method for proc entries creation
2008-04-29 08:06:22 -07:00
whitespace fixes: execution domains
2007-10-18 14:37:26 -07:00
[PATCH] split linux/file.h
2008-05-01 13:08:16 -04:00
module: Don't report discarded init pages as kernel text.
2008-01-29 17:13:18 +11:00
[PATCH] dup_fd() fixes, part 1
2008-05-16 17:22:26 -04:00
Removal of FUTEX_FD
2008-05-05 08:18:45 -07:00
futex_compat __user annotation
2008-03-30 14:18:41 -07:00
hrtimer: remove duplicate helper function
2008-05-03 18:11:48 +02:00
ITIMER_REAL: convert to use struct pid
2008-02-08 09:22:29 -08:00
kernel: use non-racy method for proc entries creation
2008-04-29 08:06:22 -07:00
sched: high-res preemption tick
2008-01-25 21:08:29 +01:00
rcu: move PREEMPT_RCU config option back under PREEMPT
2008-03-10 18:01:20 -07:00
kexec: make extended crashkernel= syntax less confusing
2008-05-01 08:04:00 -07:00
is_power_of_2: kernel/kfifo.c
2007-07-16 09:05:50 -07:00
lib: create common ascii hex array
2008-05-14 19:11:14 -07:00
[PATCH] split linux/file.h
2008-05-01 13:08:16 -04:00
kprobes: add (un)register_jprobes for batch registration
2008-04-28 08:58:32 -07:00
Kobject: convert remaining kobject_unregister() to kobject_put()
2008-01-24 20:40:40 -08:00
Deprecate find_task_by_pid()
2008-04-30 08:29:48 -07:00
kernel: use non-racy method for proc entries creation
2008-04-29 08:06:22 -07:00
Subject: lockdep: include all lock classes in all_lock_classes
2008-02-25 23:03:02 +01:00
kernel: use non-racy method for proc entries creation
2008-04-29 08:06:22 -07:00
sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
2008-05-05 23:56:18 +02:00
make marker_debug static
2008-04-30 08:29:49 -07:00
modules: proper cleanup of kobject without CONFIG_SYSFS
2008-05-23 13:09:33 +10:00
kernel: remove fastcall in kernel/*
2008-02-08 09:22:31 -08:00
kernel: remove fastcall in kernel/*
2008-02-08 09:22:31 -08:00
ipc: re-enable msgmni automatic recomputing msgmni if set to negative
2008-04-29 08:06:13 -07:00
cgroups: kernel/ns_cgroup.c should #include <linux/nsproxy.h>
2008-04-29 08:06:07 -07:00
ipc: sysvsem: refuse clone(CLONE_SYSVSEM|CLONE_NEWIPC)
2008-04-29 08:06:14 -07:00
Taint kernel after WARN_ON(condition)
2008-04-29 08:05:59 -07:00
Add new string functions strict_strto* and convert kernel params to use them
2008-02-08 09:22:41 -08:00
pids: introduce change_pid() helper
2008-04-30 08:29:48 -07:00
pidns: make pid->level and pid_ns->level unsigned
2008-04-30 08:29:49 -07:00
pm qos infrastructure and interface
2008-02-05 09:44:22 -08:00
remove div_long_long_rem
2008-05-01 08:03:58 -07:00
signals: join send_sigqueue() with send_group_sigqueue()
2008-04-30 08:29:36 -07:00
printk: don't read beyond string arguments' terminating zero
2008-04-30 08:29:52 -07:00
kernel: use non-racy method for proc entries creation
2008-04-29 08:06:22 -07:00
make generic sys_ptrace unconditional
2008-05-01 10:21:54 -07:00
Preempt-RCU: implementation
2008-01-25 21:08:24 +01:00
rcupdate: fix comment
2008-02-13 16:21:18 -08:00
generic: reduce stack pressure in sched_affinity
2008-04-19 19:44:59 +02:00
Preempt-RCU: implementation
2008-01-25 21:08:24 +01:00
kernel: explicitly include required header files under kernel/
2008-04-29 08:06:04 -07:00
Revert "relay: fix splice problem"
2008-05-08 14:06:19 +02:00
memcgroup: add the max_usage member on the res_counter
2008-04-29 08:06:10 -07:00
kernel: use non-racy method for proc entries creation
2008-04-29 08:06:22 -07:00
Don't operate with pid_t in rtmutex tester
2008-02-08 09:22:41 -08:00
Driver core: change sysdev classes to use dynamic kobject names
2008-01-24 20:40:40 -08:00
hrtimer: more hrtimer_init_sleeper() fallout.
2008-02-13 15:45:36 +01:00
Don't operate with pid_t in rtmutex tester
2008-02-08 09:22:41 -08:00
sched: mark rwsem functions as __sched for wchan/profiling
2007-12-18 15:21:13 +01:00
cgroups: fix compile warning
2008-05-14 19:11:14 -07:00
sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
2008-05-05 23:56:18 +02:00
sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
2008-05-05 23:56:18 +02:00
sched: fix weight calculations
2008-05-08 17:00:42 +02:00
sched: /debug/sched_features
2008-04-19 19:45:00 +02:00
sched: make rt_sched_class, idle_sched_class static
2008-05-05 23:56:17 +02:00
sched: fix RT task-wakeup logic
2008-05-05 23:56:18 +02:00
cpumask: use new cpus_scnprintf function
2008-04-19 19:44:59 +02:00
make seccomp zerocost in schedule
2007-07-16 09:05:50 -07:00
Revert "semaphore: fix"
2008-05-10 20:43:22 -07:00
signals: add set_restore_sigmask
2008-04-30 08:29:37 -07:00
Fix cpu hotplug problem in softirq code
2008-05-01 08:03:58 -07:00
softlockup: fix task state setting
2008-02-29 18:46:53 +01:00
spinlock: lockbreak cleanup
2008-01-30 13:31:20 +01:00
make srcu_readers_active() static
2008-02-06 10:41:02 -08:00
stop_machine: make stop_machine_run more virtualization friendly
2008-05-23 13:09:34 +10:00
pids: sys_getpgid: fix unsafe *pid usage, s/tasklist/rcu/
2008-04-30 08:29:49 -07:00
timerfd: new timerfd API
2008-02-05 09:44:07 -08:00
[PATCH] avoid multiplication overflows and signedness issues for max_fds
2008-05-16 17:22:52 -04:00
constify tables in kernel/sysctl_check.c
2008-02-08 09:22:31 -08:00
Use find_task_by_vpid in taskstats
2008-04-30 08:29:48 -07:00
kprobes: kretprobe user entry-handler
2008-02-06 10:41:11 -08:00
Make constants in kernel/timeconst.h fixed 64 bits
2008-05-02 16:18:42 -07:00
Make constants in kernel/timeconst.h fixed 64 bits
2008-05-02 16:18:42 -07:00
debugobjects: add timer specific object debugging code
2008-04-30 08:29:53 -07:00
Add scaled time to taskstats based process accounting
2007-10-18 14:37:28 -07:00
asmlinkage_protect replaces prevent_tail_call
2008-04-10 17:28:26 -07:00
alloc_uid: cleanup
2008-04-30 08:29:53 -07:00
eCryptfs: make key module subsystem respect namespaces
2008-04-29 08:06:07 -07:00
kernel: explicitly include required header files under kernel/
2008-04-29 08:06:04 -07:00
Isolate the UTS namespace's domainname and hostname back
2007-11-29 09:24:53 -08:00
kernel: remove fastcall in kernel/*
2008-02-08 09:22:31 -08:00
workqueue: remove redundant function invocation
2008-05-01 08:04:02 -07:00
3401a61e16