11 Feb, 2009
1 commit
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When we check if a task has been switched out since the last scan, we might
have a race condition on the following scenario:- the task is freshly created and scheduled
- it puts its state to TASK_UNINTERRUPTIBLE and is not yet switched out
- check_hung_task() scans this task and will report a false positive because
t->nvcsw + t->nivcsw == t->last_switch_count == 0Add a check for such cases.
Signed-off-by: Frederic Weisbecker
Acked-by: Mandeep Singh Baines
Signed-off-by: Ingo Molnar
09 Feb, 2009
1 commit
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Impact: saves sizeof(long) bytes per task_struct
By guaranteeing that sysctl_hung_task_timeout_secs have elapsed between
tasklist scans we can avoid using timestamps.Signed-off-by: Mandeep Singh Baines
Signed-off-by: Ingo Molnar
06 Feb, 2009
2 commits
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Since the tasklist is protected by rcu list operations, it is safe
to convert the read_lock()s to rcu_read_lock().Suggested-by: Peter Zijlstra
Signed-off-by: Mandeep Singh Baines
Signed-off-by: Ingo Molnar -
Impact: extend the scope of hung-task checks
Changed the default value of hung_task_check_count to PID_MAX_LIMIT.
hung_task_batch_count added to put an upper bound on the critical
section. Every hung_task_batch_count checks, the rcu lock is never
held for a too long time.Keeping the critical section small minimizes time preemption is disabled
and keeps rcu grace periods small.To prevent following a stale pointer, get_task_struct is called on g and t.
To verify that g and t have not been unhashed while outside the critical
section, the task states are checked.The design was proposed by Frédéric Weisbecker.
Signed-off-by: Mandeep Singh Baines
Suggested-by: Frédéric Weisbecker
Acked-by: Andrew Morton
Signed-off-by: Ingo Molnar
19 Jan, 2009
1 commit
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Impact: fix potential false panic
A potential race exists if sysctl_hung_task_timeout_secs is reset to 0
while inside check_hung_uniterruptible_tasks(). If check_task() is
entered, a comparison with 0 will result in a false hung_task being
detected.If sysctl_hung_task_panic is set, the system will panic.
Signed-off-by: Mandeep Singh Baines
Signed-off-by: Ingo Molnar
17 Jan, 2009
1 commit
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Fixes the following compile error:
kernel/fork.c:1049: error: 'struct task_struct' has no member named 'last_switch_count'
kernel/fork.c:1050: error: 'struct task_struct' has no member named 'last_switch_timestamp'Signed-off-by: Mandeep Singh Baines
Signed-off-by: Ingo Molnar
16 Jan, 2009
1 commit
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Decoupling allows:
* hung tasks check to happen at very low priority
* hung tasks check and softlockup to be enabled/disabled independently
at compile and/or run-time* individual panic settings to be enabled disabled independently
at compile and/or run-time* softlockup threshold to be reduced without increasing hung tasks
poll frequency (hung task check is expensive relative to softlock watchdog)* hung task check to be zero over-head when disabled at run-time
Signed-off-by: Mandeep Singh Baines
Signed-off-by: Ingo Molnar
14 Jan, 2009
3 commits
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At run-time, if softlockup_thresh is changed to a much lower value,
touch_timestamp is likely to be much older than the new softlock_thresh.This will cause a false softlockup to be detected. If softlockup_panic
is enabled, the system will panic.The fix is to touch all watchdogs before changing softlockup_thresh.
Signed-off-by: Mandeep Singh Baines
Signed-off-by: Ingo Molnar -
Impact: reduce memory footprint
add __cpuinit to rcu_init_percpu_data(), and this function's text
will be discarded after boot when !CONFIG_HOTPLUG_CPU.Signed-off-by: Lai Jiangshan
Signed-off-by: Ingo Molnar -
…/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
smp_call_function_single(): be slightly less stupid, fix #2
lockdep, mm: fix might_fault() annotation
13 Jan, 2009
2 commits
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At 37000 feet somewhere near Greenland I woke up from a half-sleep with the
realisation that __lowest_in_progress() is buggy. After landing I checked
and there were indeed 2 problems with it; this patch fixes both:
* The order of the list checks was wrong
* The locking was not correct.Signed-off-by: Arjan van de Ven
Signed-off-by: Linus Torvalds -
…l/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
kernel/sched.c: add missing forward declaration for 'double_rq_lock'
sched: partly revert "sched debug: remove NULL checking in print_cfs_rt_rq()"
cpumask: fix CONFIG_NUMA=y sched.c
12 Jan, 2009
1 commit
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fix m68k build failure:
tip/kernel/up.c: In function 'smp_call_function_single':
tip/kernel/up.c:16: error: dereferencing pointer to incomplete type
make[2]: *** [kernel/up.o] Error 1Signed-off-by: Ingo Molnar
11 Jan, 2009
6 commits
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Impact: build fix on certain configs
Added 'double_rq_lock' forward declaration, allowing double_rq_lock
to be used in _double_lock_balance().Signed-off-by: Steven Noonan
Signed-off-by: Ingo Molnar -
Impact: build fix on Alpha
kernel/up.c: In function 'smp_call_function_single':
kernel/up.c:12: error: 'cpuid' undeclared (first use in this function)
kernel/up.c:12: error: (Each undeclared identifier is reported only once
kernel/up.c:12: error: for each function it appears in.)The typo didnt show up on x86 because 'cpuid' happens to be a
function address as well ...Signed-off-by: Ingo Molnar
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If you do
smp_call_function_single(expression-with-side-effects, ...)
then expression-with-side-effects never gets evaluated on UP builds.
As always, implementing it in C is the correct thing to do.
While we're there, uninline it for size and possible header dependency
reasons.And create a new kernel/up.c, as a place in which to put
uniprocessor-specific code and storage. It should mirror kernel/smp.c.Signed-off-by: Andrew Morton
Signed-off-by: Ingo Molnar -
Impact: avoid accessing NULL tg.css->cgroup
In commit 0a0db8f5c9d4bbb9bbfcc2b6cb6bce2d0ef4d73d, I removed checking
NULL tg.css->cgroup, but I realized I was wrong when I found reading
/proc/sched_debug can race with cgroup_create().Signed-off-by: Li Zefan
Signed-off-by: Ingo Molnar -
Impact: fix panic on ia64 with NR_CPUS=1024
struct sched_domain is now a dangling structure; where we really want
static ones, we need to use static_sched_domain.(As the FIXME in this file says, cpumask_var_t would be better, but
this code is hairy enough without trying to add initialization code to
the right places).Reported-by: Mike Travis
Signed-off-by: Rusty Russell
Signed-off-by: Ingo Molnar
10 Jan, 2009
8 commits
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* git://git.kernel.org/pub/scm/linux/kernel/git/arjan/linux-2.6-async-2:
async: make async a command line option for now
partial revert of asynchronous inode delete -
* git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-nommu:
NOMMU: Support XIP on initramfs
NOMMU: Teach kobjsize() about VMA regions.
FLAT: Don't attempt to expand the userspace stack to fill the space allocated
FDPIC: Don't attempt to expand the userspace stack to fill the space allocated
NOMMU: Improve procfs output using per-MM VMAs
NOMMU: Make mmap allocation page trimming behaviour configurable.
NOMMU: Make VMAs per MM as for MMU-mode linux
NOMMU: Delete askedalloc and realalloc variables
NOMMU: Rename ARM's struct vm_region
NOMMU: Fix cleanup handling in ramfs_nommu_get_umapped_area() -
…s/security-testing-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6:
CRED: Fix commit_creds() on a process that has no mm -
... and have it default off.
This does allow people to work with it for testing.Signed-off-by: Arjan van de Ven
-
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rric/oprofile: (31 commits)
powerpc/oprofile: fix whitespaces in op_model_cell.c
powerpc/oprofile: IBM CELL: add SPU event profiling support
powerpc/oprofile: fix cell/pr_util.h
powerpc/oprofile: IBM CELL: cleanup and restructuring
oprofile: make new cpu buffer functions part of the api
oprofile: remove #ifdef CONFIG_OPROFILE_IBS in non-ibs code
ring_buffer: fix ring_buffer_event_length()
oprofile: use new data sample format for ibs
oprofile: add op_cpu_buffer_get_data()
oprofile: add op_cpu_buffer_add_data()
oprofile: rework implementation of cpu buffer events
oprofile: modify op_cpu_buffer_read_entry()
oprofile: add op_cpu_buffer_write_reserve()
oprofile: rename variables in add_ibs_begin()
oprofile: rename add_sample() in cpu_buffer.c
oprofile: rename variable ibs_allowed to has_ibs in op_model_amd.c
oprofile: making add_sample_entry() inline
oprofile: remove backtrace code for ibs
oprofile: remove unused ibs macro
oprofile: remove unused components in struct oprofile_cpu_buffer
... -
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (94 commits)
ACPICA: hide private headers
ACPICA: create acpica/ directory
ACPI: fix build warning
ACPI : Use RSDT instead of XSDT by adding boot option of "acpi=rsdt"
ACPI: Avoid array address overflow when _CST MWAIT hint bits are set
fujitsu-laptop: Simplify SBLL/SBL2 backlight handling
fujitsu-laptop: Add BL power, LED control and radio state information
ACPICA: delete utcache.c
ACPICA: delete acdisasm.h
ACPICA: Update version to 20081204.
ACPICA: FADT: Update error msgs for consistency
ACPICA: FADT: set acpi_gbl_use_default_register_widths to TRUE by default
ACPICA: FADT parsing changes and fixes
ACPICA: Add ACPI_MUTEX_TYPE configuration option
ACPICA: Fixes for various ACPI data tables
ACPICA: Restructure includes into public/private
ACPI: remove private acpica headers from driver files
ACPI: reboot.c: use new acpi_reset interface
ACPICA: New: acpi_reset interface - write to reset register
ACPICA: Move all public H/W interfaces to new hwxface
... -
The newly allocated creds in prepare_kernel_cred() must be initialised
before get_uid() and get_group_info() can access them. They should be
copied from the old credentials.Reported-by: Steve Dickson
Signed-off-by: David Howells
Acked-by: Steve Dickson
Signed-off-by: Linus Torvalds -
Missing put_cred() in the error handling path of prepare_kernel_cred().
Signed-off-by: David Howells
Acked-by: Steve Dickson
Signed-off-by: Linus Torvalds
09 Jan, 2009
13 commits
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turns out that there are real problems with allowing async
tasks that are scheduled from async tasks to run after
the async_synchronize_full() returns.This patch makes the _full more strict and a complete
synchronization. Later I might need to add back a lighter
form of synchronization for other uses.. but not right now.Signed-off-by: Arjan van de Ven
Signed-off-by: Linus Torvalds -
Use the new generic implementation.
Signed-off-by: Wu Fengguang
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Currently task_active_pid_ns is not safe to call after a task becomes a
zombie and exit_task_namespaces is called, as nsproxy becomes NULL. By
reading the pid namespace from the pid of the task we can trivially solve
this problem at the cost of one extra memory read in what should be the
same cacheline as we read the namespace from.When moving things around I have made task_active_pid_ns out of line
because keeping it in pid_namespace.h would require adding includes of
pid.h and sched.h that I don't think we want.This change does make task_active_pid_ns unsafe to call during
copy_process until we attach a pid on the task_struct which seems to be a
reasonable trade off.Signed-off-by: Eric W. Biederman
Signed-off-by: Sukadev Bhattiprolu
Cc: Oleg Nesterov
Cc: Roland McGrath
Cc: Bastian Blank
Cc: Pavel Emelyanov
Cc: Nadia Derbey
Acked-by: Serge Hallyn
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Impact: cleanups, use new cpumask API
Final trivial cleanups: mainly s/cpumask_t/struct cpumask
Note there is a FIXME in generate_sched_domains(). A future patch will
change struct cpumask *doms to struct cpumask *doms[].
(I suppose Rusty will do this.)Signed-off-by: Li Zefan
Cc: Ingo Molnar
Cc: Rusty Russell
Acked-by: Mike Travis
Cc: Paul Menage
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Impact: use new cpumask API
This patch mainly does the following things:
- change cs->cpus_allowed from cpumask_t to cpumask_var_t
- call alloc_bootmem_cpumask_var() for top_cpuset in cpuset_init_early()
- call alloc_cpumask_var() for other cpusets
- replace cpus_xxx() to cpumask_xxx()Signed-off-by: Li Zefan
Cc: Ingo Molnar
Cc: Rusty Russell
Acked-by: Mike Travis
Cc: Paul Menage
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Impact: cleanups, reduce stack usage
This patch prepares for the next patch. When we convert
cpuset.cpus_allowed to cpumask_var_t, (trialcs = *cs) no longer works.Another result of this patch is reducing stack usage of trialcs.
sizeof(*cs) can be as large as 148 bytes on x86_64, so it's really not
good to have it on stack.Signed-off-by: Li Zefan
Cc: Ingo Molnar
Cc: Rusty Russell
Acked-by: Mike Travis
Cc: Paul Menage
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Impact: reduce stack usage
Allocate a global cpumask_var_t at boot, and use it in cpuset_attach(), so
we won't fail cpuset_attach().Signed-off-by: Li Zefan
Cc: Ingo Molnar
Cc: Rusty Russell
Acked-by: Mike Travis
Cc: Paul Menage
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Impact: reduce stack usage
Just use cs->cpus_allowed, and no need to allocate a cpumask_var_t.
Signed-off-by: Li Zefan
Cc: Ingo Molnar
Cc: Rusty Russell
Acked-by: Mike Travis
Cc: Paul Menage
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This patchset converts cpuset to use new cpumask API, and thus
remove on stack cpumask_t to reduce stack usage.Before:
# cat kernel/cpuset.c include/linux/cpuset.h | grep -c cpumask_t
21
After:
# cat kernel/cpuset.c include/linux/cpuset.h | grep -c cpumask_t
0This patch:
Impact: reduce stack usage
It's safe to call cpulist_scnprintf inside callback_mutex, and thus we can
just remove the cpumask_t and no need to allocate a cpumask_var_t.Signed-off-by: Li Zefan
Cc: Ingo Molnar
Cc: Rusty Russell
Acked-by: Mike Travis
Cc: Paul Menage
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
I found a bug on my dual-cpu box. I created a sub cpuset in top cpuset
and assign 1 to its cpus. And then we attach some tasks into this sub
cpuset. After this, we offline CPU1. Now, the tasks in this new cpuset
are moved into top cpuset automatically because there is no cpu in sub
cpuset. Then we online CPU1, we find all the tasks which doesn't belong
to top cpuset originally just run on CPU0.We fix this bug by setting task's cpu_allowed to cpu_possible_map when
attaching it into top cpuset. This method needn't modify the current
behavior of cpusets on CPU hotplug, and all of tasks in top cpuset use
cpu_possible_map to initialize their cpu_allowed.Signed-off-by: Miao Xie
Cc: Paul Menage
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
task_cs() calls task_subsys_state().
We must use rcu_read_lock() to protect cgroup_subsys_state().
It's correct that top_cpuset is never freed, but cgroup_subsys_state()
accesses css_set, this css_set maybe freed when task_cs() called.We use use rcu_read_lock() to protect it.
Signed-off-by: Lai Jiangshan
Acked-by: Paul Menage
Cc: KAMEZAWA Hiroyuki
Cc: Pavel Emelyanov
Cc: Balbir Singh
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
