request_irq() calls into proc code via __setup_irq() which is not safe
in an atomic context, so request_irq() can itself use the more
reliable GFP_KERNEL allocation for the action descriptor.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
I enabled all cgroup subsystems when compiling kernel, and then:
# mount -t cgroup -o net_cls xxx /mnt
# mkdir /mnt/0
This showed up immediately:
BUG: MAX_LOCKDEP_SUBCLASSES too low!
turning off the locking correctness validator.
It's caused by the cgroup hierarchy lock:
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
if (ss->root == root)
mutex_lock_nested(&ss->hierarchy_mutex, i);
}
Now we have 9 cgroup subsystems, and the above 'i' for net_cls is 8, but
MAX_LOCKDEP_SUBCLASSES is 8.
This patch uses different lockdep keys for different subsystems.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We need to pass an unsigned long as the minimum, because it gets casted
to an unsigned long in the sysctl handler. If we pass an int, we'll
access four more bytes on 64bit arches, resulting in a random minimum
value.
[rientjes@google.com: fix type of `old_bytes']
Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Catalin noticed that (38d47c1b7075: futex: rely on get_user_pages() for
shared futexes) caused an mm_struct leak.
Some tracing with the function graph tracer quickly pointed out that
futex_wait() has exit paths with unbalanced reference counts.
This regression was discovered by kmemleak.
Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
timers: fix TIMER_ABSTIME for process wide cpu timers
timers: split process wide cpu clocks/timers, fix
x86: clean up hpet timer reinit
timers: split process wide cpu clocks/timers, remove spurious warning
timers: split process wide cpu clocks/timers
signal: re-add dead task accumulation stats.
x86: fix hpet timer reinit for x86_64
sched: fix nohz load balancer on cpu offline
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
ptrace, x86: fix the usage of ptrace_fork()
i8327: fix outb() parameter order
x86: fix math_emu register frame access
x86: math_emu info cleanup
x86: include correct %gs in a.out core dump
x86, vmi: put a missing paravirt_release_pmd in pgd_dtor
x86: find nr_irqs_gsi with mp_ioapic_routing
x86: add clflush before monitor for Intel 7400 series
x86: disable intel_iommu support by default
x86: don't apply __supported_pte_mask to non-present ptes
x86: fix grammar in user-visible BIOS warning
x86/Kconfig.cpu: make Kconfig help readable in the console
x86, 64-bit: print DMI info in the oops trace
Intel reported a 10% regression (mysql+sysbench) on a 16-way machine
with these patches:
1596e29: sched: symmetric sync vs avg_overlap
d942fb6: sched: fix sync wakeups
Revert them.
Reported-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Bisected-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The POSIX timer interface allows for absolute time expiry values through the
TIMER_ABSTIME flag, therefore we have to synchronize the timer to the clock
every time we start it.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
To decrease the chance of a missed enable, always enable the timer when we
sample it, we'll always disable it when we find that there are no active timers
in the jiffy tick.
This fixes a flood of warnings reported by Mike Galbraith.
Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
I noticed by pure accident we have ptrace_fork() and friends. This was
added by "x86, bts: add fork and exit handling", commit
bf53de907dfdaac178c92d774aae7370d7b97d20.
I can't test this, ds_request_bts() returns -EOPNOTSUPP, but I strongly
believe this needs the fix. I think something like this program
int main(void)
{
int pid = fork();
if (!pid) {
ptrace(PTRACE_TRACEME, 0, NULL, NULL);
kill(getpid(), SIGSTOP);
fork();
} else {
struct ptrace_bts_config bts = {
.flags = PTRACE_BTS_O_ALLOC,
.size = 4 * 4096,
};
wait(NULL);
ptrace(PTRACE_SETOPTIONS, pid, NULL, PTRACE_O_TRACEFORK);
ptrace(PTRACE_BTS_CONFIG, pid, &bts, sizeof(bts));
ptrace(PTRACE_CONT, pid, NULL, NULL);
sleep(1);
}
return 0;
}
should crash the kernel.
If the task is traced by its natural parent ptrace_reparented() returns 0
but we should clear ->btsxxx anyway.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Andrew had some suggestions for the latencytop file; this patch takes care
of most of these:
* Add documentation
* Turn account_scheduler_latency into an inline function
* Don't report negative values to userspace
* Make the file operations struct const
* Fix a few checkpatch.pl warnings
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix broken /proc/profile on UP machines
Commit c309b917cab55799ea489d7b5f1b77025d9f8462 "cpumask: convert
kernel/profile.c" broke profiling. prof_cpu_mask was previously
initialized to CPU_MASK_ALL, but left uninitialized in that commit.
We need to copy cpu_possible_mask (cpu_online_mask is not enough).
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: no default -fno-stack-protector if stackp is enabled, cleanup
Stackprotector make rules had the following problems.
* cc support test and warning are scattered across makefile and
kernel/panic.c.
* -fno-stack-protector was always added regardless of configuration.
Update such that cc support test and warning are contained in makefile
and -fno-stack-protector is added iff stackp is turned off. While at
it, prepare for 32bit support.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
ELF core dump is used for both user land core dump and kernel crash
dump. Depending on architecture, register might need to be accessed
differently for userland and kernel. Allow architectures to define
ELF_CORE_COPY_KERNEL_REGS() and use different operation for kernel
register dump.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
While being at it make every occurrence of 'do_irq_select_affinity'
have the same signature in terms of signedness of the first argument.
Fix this sparse warning:
kernel/irq/manage.c:112:5: warning: symbol 'do_irq_select_affinity' was not declared. Should it be static?
Also rename do_irq_select_affinity() to setup_affinity() - shorter name
and clearer naming.
Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Acked-by: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Simplify and make init_kstat_irqs etc more type proof, suggested by
Andrew.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: get correct kstat_irqs [/proc/interrupts] for msi/msi-x etc
need to call clear_kstat_irqs(), so when we reuse that irq_desc,
we get correct kstat in /proc/interrupts.
This makes /proc/interrupts not have <NULL> entries.
Don't need to worry about arch that doesn't support genirq, because they
will not call dynamic_irq_cleanup().
v2: simplify and make clear_kstat_irqs more robust
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
list.h provides a dedicated primitive for
"list_del followed by list_add_tail"... list_move_tail.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Rename the async_*_special() functions to async_*_domain(), which
describes the purpose of these functions much better.
[Broke up long lines to silence checkpatch]
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Add some kerneldoc to the async interface.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
If we fail to create the manager thread, fall back to non-fastboot.
If we fail to create an async thread, try again after waiting for
a bit.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
async_schedule() should pass in async_running as the running
list, and run_one_entry() should put the entry to be run on
the provided running list instead of always on the generic one.
Reported-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
I happened to forked lots of processes, and hit NULL pointer dereference.
It is because in copy_process() after checking max_threads, 0 is returned
but not -EAGAIN.
The bug is introduced by "CRED: Detach the credentials from task_struct"
(commit f1752eec6145c97163dbce62d17cf5d928e28a27).
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With exclusive waiters, every process woken up through the wait queue must
ensure that the next waiter down the line is woken when it has finished.
Interruptible waiters don't do that when aborting due to a signal. And if
an aborting waiter is concurrently woken up through the waitqueue, noone
will ever wake up the next waiter.
This has been observed with __wait_on_bit_lock() used by
lock_page_killable(): the first contender on the queue was aborting when
the actual lock holder woke it up concurrently. The aborted contender
didn't acquire the lock and therefor never did an unlock followed by
waking up the next waiter.
Add abort_exclusive_wait() which removes the process' wait descriptor from
the waitqueue, iff still queued, or wakes up the next waiter otherwise.
It does so under the waitqueue lock. Racing with a wake up means the
aborting process is either already woken (removed from the queue) and will
wake up the next waiter, or it will remove itself from the queue and the
concurrent wake up will apply to the next waiter after it.
Use abort_exclusive_wait() in __wait_event_interruptible_exclusive() and
__wait_on_bit_lock() when they were interrupted by other means than a wake
up through the queue.
[akpm@linux-foundation.org: coding-style fixes]
Reported-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Mentored-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Chuck Lever <cel@citi.umich.edu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org> ["after some testing"]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Revert commit 0c2d64fb6cae9aae480f6a46cfe79f8d7d48b59f because it causes
(arguably poorly designed) existing userspace to spend interminable
periods closing billions of not-open file descriptors.
We could bring this back, with some sort of opt-in tunable in /proc, which
defaults to "off".
Peter's alanysis follows:
: I spent several hours trying to get to the bottom of a serious
: performance issue that appeared on one of our servers after upgrading to
: 2.6.28. In the end it's what could be considered a userspace bug that
: was triggered by a change in 2.6.28. Since this might also affect other
: people I figured I'd at least document what I found here, and maybe we
: can even do something about it:
:
:
: So, I upgraded some of debian.org's machines to 2.6.28.1 and immediately
: the team maintaining our ftp archive complained that one of their
: scripts that previously ran in a few minutes still hadn't even come
: close to being done after an hour or so. Downgrading to 2.6.27 fixed
: that.
:
: Turns out that script is forking a lot and something in it or python or
: whereever closes all the file descriptors it doesn't want to pass on.
: That is, it starts at zero and goes up to ulimit -n/RLIMIT_NOFILE and
: closes them all with a few exceptions.
:
: Turns out that takes a long time when your limit -n is now 2^20 (1048576).
:
: With 2.6.27.* the ulimit -n was the standard 1024, but with 2.6.28 it is
: now a thousand times that.
:
: 2.6.28 included a patch titled "rlimit: permit setting RLIMIT_NOFILE to
: RLIM_INFINITY" (0c2d64fb6cae9aae480f6a46cfe79f8d7d48b59f)[1] that
: allows, as the title implies, to set the limit for number of files to
: infinity.
:
: Closer investigation showed that the broken default ulimit did not apply
: to "system" processes (like stuff started from init). In the end I
: could establish that all processes that passed through pam_limit at one
: point had the bad resource limit.
:
: Apparently the pam library in Debian etch (4.0) initializes the limits
: to some default values when it doesn't have any settings in limit.conf
: to override them. Turns out that for nofiles this is RLIM_INFINITY.
: Commenting out "case RLIMIT_NOFILE" in pam_limit.c:267 of our pam
: package version 0.79-5 fixes that - tho I'm not sure what side effects
: that has.
:
: Debian lenny (the upcoming 5.0 version) doesn't have this issue as it
: uses a different pam (version).
Reported-by: Peter Palfrader <weasel@debian.org>
Cc: Adam Tkac <vonsch@gmail.com>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: <stable@kernel.org> [2.6.28.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
alpha:
kernel/async.c: In function 'run_one_entry':
kernel/async.c:141: warning: format '%lli' expects type 'long long int', but argument 2 has type 'async_cookie_t'
kernel/async.c:149: warning: format '%lli' expects type 'long long int', but argument 2 has type 'async_cookie_t'
kernel/async.c:149: warning: format '%lld' expects type 'long long int', but argument 4 has type 's64'
kernel/async.c: In function 'async_synchronize_cookie_special':
kernel/async.c:250: warning: format '%lli' expects type 'long long int', but argument 3 has type 's64'
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change the process wide cpu timers/clocks so that we:
1) don't mess up the kernel with too many threads,
2) don't have a per-cpu allocation for each process,
3) have no impact when not used.
In order to accomplish this we're going to split it into two parts:
- clocks; which can take all the time they want since they run
from user context -- ie. sys_clock_gettime(CLOCK_PROCESS_CPUTIME_ID)
- timers; which need constant time sampling but since they're
explicity used, the user can pay the overhead.
The clock readout will go back to a full sum of the thread group, while the
timers will run of a global 'clock' that only runs when needed, so only
programs that make use of the facility pay the price.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We're going to split the process wide cpu accounting into two parts:
- clocks; which can take all the time they want since they run
from user context.
- timers; which need constant time tracing but can affort the overhead
because they're default off -- and rare.
The clock readout will go back to a full sum of the thread group, for this
we need to re-add the exit stats that were removed in the initial itimer
rework (f06febc9: timers: fix itimer/many thread hang).
Furthermore, since that full sum can be rather slow for large thread groups
and we have the complete dead task stats, revert the do_notify_parent time
computation.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: APIC: enable workaround on AMD Fam10h CPUs
xen: disable interrupts before saving in percpu
x86: add x86@kernel.org to MAINTAINERS
x86: push old stack address on irqstack for unwinder
irq, x86: fix lock status with numa_migrate_irq_desc
x86: add cache descriptors for Intel Core i7
x86/Voyager: make it build and boot
Christian Borntraeger reports:
> After a logical cpu offline, even on a complete idle system, there
> is one cpu with full ticks. It turns out that nohz.cpu_mask has the
> the offlined cpu still set.
>
> In select_nohz_load_balancer() we check if the system is completely
> idle to turn of load balancing. We compare cpu_online_map with
> nohz.cpu_mask. Since cpu_online_map is updated on cpu unplug,
> but nohz.cpu_mask is not, the check fails and the scheduler believes
> that we need an "idle load balancer" even on a fully idle system.
> Since the ilb cpu does not deactivate the timer tick this breaks NOHZ.
Fix the select_nohz_load_balancer() to not set the nohz.cpu_mask
while a cpu is going offline.
Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
"ftrace: use struct pid" commit 978f3a45d9499c7a447ca7615455cefb63d44165
converted ftrace_pid_trace to "struct pid*".
But we can't use do_each_pid_task() without rcu_read_lock() even if
we know the pid itself can't go away (it was pinned in ftrace_pid_write).
The exiting task can detach itself from this pid at any moment.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched_rt: don't use first_cpu on cpumask created with cpumask_and
sched: fix buddie group latency
sched: clear buddies more aggressively
sched: symmetric sync vs avg_overlap
sched: fix sync wakeups
cpuset: fix possible deadlock in async_rebuild_sched_domains
Current refcounting for modules (done if CONFIG_MODULE_UNLOAD=y) is
using a lot of memory.
Each 'struct module' contains an [NR_CPUS] array of full cache lines.
This patch uses existing infrastructure (percpu_modalloc() &
percpu_modfree()) to allocate percpu space for the refcount storage.
Instead of wasting NR_CPUS*128 bytes (on i386), we now use
nr_cpu_ids*sizeof(local_t) bytes.
On a typical distro, where NR_CPUS=8, shiping 2000 modules, we reduce
size of module files by about 2 Mbytes. (1Kb per module)
Instead of having all refcounters in the same memory node - with TLB misses
because of vmalloc() - this new implementation permits to have better
NUMA properties, since each CPU will use storage on its preferred node,
thanks to percpu storage.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Eric Paris reported:
> I have an hp dl785g5 which is unable to successfully run
> 2.6.29-0.66.rc3.fc11.x86_64 or 2.6.29-rc2-next-20090126. During bootup
> (early in userspace daemons starting) I get the below BUG, which quickly
> renders the machine dead. I assume it is because sparse_irq_lock never
> gets released when the BUG kills that task.
Adjust lock sequence when migrating a descriptor with
CONFIG_NUMA_MIGRATE_IRQ_DESC enabled.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
cpumask_and() only initializes nr_cpu_ids bits, so the (deprecated)
first_cpu() might find one of those uninitialized bits if nr_cpu_ids
is less than NR_CPUS (as it can be for CONFIG_CPUMASK_OFFSTACK).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Similar to the previous patch, by not clearing buddies we can select entities
past their run quota, which can increase latency. This means we have to clear
group buddies as well.
Do not use the group clear for pick_next_task(), otherwise that'll get O(n^2).
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
It was noticed that a task could get re-elected past its run quota due to buddy
affinities. This could increase latency a little. Cure it by more aggresively
clearing buddy state.
We do so in two situations:
- when we force preempt
- when we select a buddy to run
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
