Right now we don't output vfork events. Even though we should
always see an exec after a vfork, we may get perfcounter
samples between the vfork and exec. These samples can lead to
some confusion when parsing perfcounter data.
To keep things consistent we should always log a fork event. It
will result in a little more log data, but is less confusing to
trace parsing tools.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090716104817.589309391@samba.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There are a few places we are leaking tiny amounts of kernel
memory to userspace. This happens when writing out strings
because we always align the end to 64 bits.
To avoid this we should always use an appropriately sized
temporary buffer and ensure it is zeroed.
Since d_path assembles the string from the end of the buffer
backwards, we need to add 64 bits after the buffer to allow for
alignment.
We also need to copy arch_vma_name to the temporary buffer,
because if we use it directly we may end up copying to
userspace a number of bytes after the end of the string
constant.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090716104817.273972048@samba.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
I spotted two sites that didn't take vruntime wrap-around into
account. Fix these by creating a comparison helper that does do
so.
Signed-off-by: Fabio Checconi <fabio@gandalf.sssup.it>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We can directly use %pf input format instead of kallsyms_lookup()
and %s input format
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
We can directly use %pF input format instead of sprint_symbol()
and %s input format.
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Rewrite the __ftrace_replace_code() function, simplify it, but don't
change the code's logic.
First, we get the state we want to set, if the record has the same
state, then do nothing, otherwise enable/disable it.
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
ftrace_trace_onoff_callback() will return an error even if we do the
right operation, for example:
# echo _spin_*:traceon:10 > set_ftrace_filter
-bash: echo: write error: Invalid argument
# cat set_ftrace_filter
#### all functions enabled ####
_spin_trylock_bh:traceon:count=10
_spin_unlock_irq:traceon:count=10
_spin_unlock_bh:traceon:count=10
_spin_lock_irq:traceon:count=10
_spin_unlock:traceon:count=10
_spin_trylock:traceon:count=10
_spin_unlock_irqrestore:traceon:count=10
_spin_lock_irqsave:traceon:count=10
_spin_lock_bh:traceon:count=10
_spin_lock:traceon:count=10
We want to set _spin_*:traceon:10 to set_ftrace_filter, it complains
with "Invalid argument", but the operation is successful.
This is because ftrace_process_regex() returns the number of functions that
matched the pattern. If the number is not 0, this value is returned
by ftrace_regex_write() whereas we want to return the number of bytes
virtually written.
Also the file offset pointer is not updated in this case.
If the number of matched functions is lower than the number of bytes written
by the user, this results to a reprocessing of the string given by the user with
a lower size, leading to a malformed ftrace regex and then a -EINVAL returned.
So, this patch fixes it by returning 0 if no error occured.
The fix also applies on 2.6.30
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: stable@kernel.org
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
kernel/trace/ring_buffer.c: In function 'rb_tail_page_update':
kernel/trace/ring_buffer.c:849: warning: value computed is not used
kernel/trace/ring_buffer.c:850: warning: value computed is not used
Add "(void)"s to fix this warning, because we don't need here to handle
the fail case of cmpxchg, it's fine if an interrupt already did the
job.
Changed from V1:
Add a comment(which is written by Steven) for it.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/peterz/linux-2.6-sched:
sched: Fix bug in SCHED_IDLE interaction with group scheduling
sched: Fix rt_rq->pushable_tasks initialization in init_rt_rq()
sched: Reset sched stats on fork()
sched_rt: Fix overload bug on rt group scheduling
sched: Documentation/sched-rt-group: Fix style issues & bump version
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
hrtimer: Fix migration expiry check
hrtimer: migration: do not check expiry time on current CPU
* 'core-fixes-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
futexes: Fix infinite loop in get_futex_key() on huge page
The per cpu variable stat is freeded if we fail to allocate a name
on start up. This was due to stat at first being allocated in the
initial design. But since then, it has become a static per cpu variable
but the free on error was not removed.
Also added __init annotation to the function that this is in.
[ Impact: prevent possible memory corruption on low mem at boot up ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fix a missed rename in EVENT_PROFILE support so that it gets
built and allows tracepoint tracing from the 'perf' tool.
Fix a typo in the (never before built & enabled) portion in
perf_counter.c as well, and update that code to the
attr.config changes as well.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ben Gamari <bgamari.foss@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1246869094-21237-1-git-send-email-chris@chris-wilson.co.uk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This makes generic netlink network namespace aware. No
generic netlink families except for the controller family
are made namespace aware, they need to be checked one by
one and then set the family->netnsok member to true.
A new function genlmsg_multicast_netns() is introduced to
allow sending a multicast message in a given namespace,
for example when it applies to an object that lives in
that namespace, a new function genlmsg_multicast_allns()
to send a message to all network namespaces (for objects
that do not have an associated netns).
The function genlmsg_multicast() is changed to multicast
the message in just init_net, which is currently correct
for all generic netlink families since they only work in
init_net right now. Some will later want to work in all
net namespaces because they do not care about the netns
at all -- those will have to be converted to use one of
the new functions genlmsg_multicast_allns() or
genlmsg_multicast_netns() whenever they are made netns
aware in some way.
After this patch families can easily decide whether or
not they should be available in all net namespaces. Many
genl families us it for objects not related to networking
and should therefore be available in all namespaces, but
that will have to be done on a per family basis.
Note that this doesn't touch on the checkpoint/restart
problem where network namespaces could be used, genl
families and multicast groups are numbered globally and
I see no easy way of changing that, especially since it
must be possible to multicast to all network namespaces
for those families that do not care about netns.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'kmemleak' of git://linux-arm.org/linux-2.6:
kmemleak: Remove alloc_bootmem annotations introduced in the past
kmemleak: Add callbacks to the bootmem allocator
kmemleak: Allow partial freeing of memory blocks
kmemleak: Trace the kmalloc_large* functions in slub
kmemleak: Scan objects allocated during a scanning episode
kmemleak: Do not acquire scan_mutex in kmemleak_open()
kmemleak: Remove the reported leaks number limitation
kmemleak: Add more cond_resched() calls in the scanning thread
kmemleak: Renice the scanning thread to +10
* Remove smp_lock.h from files which don't need it (including some headers!)
* Add smp_lock.h to files which do need it
* Make smp_lock.h include conditional in hardirq.h
It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT
This will make hardirq.h inclusion cheaper for every PREEMPT=n config
(which includes allmodconfig/allyesconfig, BTW)
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
get_futex_key() can infinitely loop if it is called on a
virtual address that is within a huge page but not aligned to
the beginning of that page. The call to get_user_pages_fast
will return the struct page for a sub-page within the huge page
and the check for page->mapping will always fail.
The fix is to call compound_head on the page before checking
that it's mapped.
Signed-off-by: Sonny Rao <sonnyrao@us.ibm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org
Cc: anton@samba.org
Cc: rajamony@us.ibm.com
Cc: speight@us.ibm.com
Cc: mstephen@us.ibm.com
Cc: grimm@us.ibm.com
Cc: mikey@ozlabs.au.ibm.com
LKML-Reference: <20090710231313.GA23572@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
One of the isolation modifications for SCHED_IDLE is the
unitization of sleeper credit. However the check for this
assumes that the sched_entity we're placing always belongs to a
task.
This is potentially not true with group scheduling and leaves
us rummaging randomly when we try to pull the policy.
Signed-off-by: Paul Turner <pjt@google.com>
Cc: peterz@infradead.org
LKML-Reference: <alpine.DEB.1.00.0907101649570.29914@kitami.corp.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'core-fixes-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
dma-debug: Fix the overlap() function to be correct and readable
oprofile: reset bt_lost_no_mapping with other stats
x86/oprofile: rename kernel parameter for architectural perfmon to arch_perfmon
signals: declare sys_rt_tgsigqueueinfo in syscalls.h
rcu: Mark Hierarchical RCU no longer experimental
dma-debug: Put all hash-chain locks into the same lock class
dma-debug: fix off-by-one error in overlap function
Optimize cond_resched() by removing one conditional.
Currently cond_resched() checks system_state ==
SYSTEM_RUNNING in order to avoid scheduling before the
scheduler is running.
We can however, as per suggestion of Matt, use
PREEMPT_ACTIVE to accomplish that very same.
Suggested-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
tracing: Fix trace_print_seq()
kprobes: No need to unlock kprobe_insn_mutex
tracing/fastboot: Document the need of initcall_debug
trace_export: Repair missed fields
tracing: Fix stack tracer sysctl handling
The timer migration expiry check should prevent the migration of a
timer to another CPU when the timer expires before the next event is
scheduled on the other CPU. Migrating the timer might delay it because
we can not reprogram the clock event device on the other CPU. But the
code implementing that check has two flaws:
- for !HIGHRES the check compares the expiry value with the clock
events device expiry value which is wrong for CLOCK_REALTIME based
timers.
- the check is racy. It holds the hrtimer base lock of the target CPU,
but the clock event device expiry value can be modified
nevertheless, e.g. by an timer interrupt firing.
The !HIGHRES case is easy to fix as we can enqueue the timer on the
cpu which was selected by the load balancer. It runs the idle
balancing code once per jiffy anyway. So the maximum delay for the
timer is the same as when we keep the tick on the current cpu going.
In the HIGHRES case we can get the next expiry value from the hrtimer
cpu_base of the target CPU and serialize the update with the cpu_base
lock. This moves the lock section in hrtimer_interrupt() so we can set
next_event to KTIME_MAX while we are handling the expired timers and
set it to the next expiry value after we handled the timers under the
base lock. While the expired timers are processed timer migration is
blocked because the expiry time of the timer is always <= KTIME_MAX.
Also remove the now useless clockevents_get_next_event() function.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The timer migration code needs to check whether the expiry time of the
timer is before the programmed clock event expiry time when the timer
is enqueued on another CPU because we can not reprogram the timer
device on the other CPU. The current logic checks the expiry time even
if we enqueue on the current CPU when nohz_get_load_balancer() returns
current CPU. This might lead to an endless loop in the expiry check
code when the expiry time of the timer is before the current
programmed next event.
Check whether nohz_get_load_balancer() returns current CPU and skip
the expiry check if this is the case.
The bug was triggered from the networking code. The patch fixes the
regression http://bugzilla.kernel.org/show_bug.cgi?id=13738
(Soft-Lockup/Race in networking in 2.6.31-rc1+195)
Cc: Arun Bharadwaj <arun@linux.vnet.ibm.com
Tested-by: Joao Correia <joaomiguelcorreia@gmail.com>
Tested-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
When logging to console is disabled from userspace using klogctl()
and later re-enabled, console_loglevel gets set to the default
log level instead to the previous value.
This means that if the kernel was booted with 'quiet', the boot is
suddenly no longer quiet after logging to console gets re-enabled.
Save the current console_loglevel when logging is disabled and
restore to that value. If the log level is set to a specific value
while disabled, this is interpreted as an implicit re-enabling of
the logging.
The problem that prompted this patch is described in:
http://lkml.org/lkml/2009/6/28/234
There are two variations possible on the patch below:
1) If klogctl(7) is called while logging is not disabled, then set level
to default (partially preserving current functionality):
case 7: /* Enable logging to console */
- console_loglevel = default_console_loglevel;
+ if (saved_console_loglevel == -1)
+ console_loglevel = default_console_loglevel;
+ else {
+ console_loglevel = saved_console_loglevel;
+ saved_console_loglevel = -1;
+ }
2) If klogctl(8) is called while logging is disabled, then don't enable
logging, but remember the requested value for when logging does get
enabled again:
case 8: /* Set level of messages printed to console */
[...]
- console_loglevel = len;
+ if (saved_console_loglevel == -1)
+ console_loglevel = len;
+ else
+ saved_console_loglevel = len;
Yet another option would be to ignore the request.
Signed-off-by: Frans Pop <elendil@planet.nl>
Cc: cryptsetup@packages.debian.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <200907061331.49930.elendil@planet.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Today, when a console is registered without CON_PRINTBUFFER,
end users never see the announcement of it being added, and
never know if they missed something, if the console is really
at the start or not, and just leads to general confusion.
This re-orders existing code, to make sure the console is
added, before the "console [%s%d] enabled" is printed out -
ensuring that this message is _always_ seen.
This has the desired/intended side effect of making sure that
"console enabled:" messages are printed on the bootconsole, and
the real console. This does cause the same line is printed
twice if the bootconsole and real console are the same device,
but if they are on different devices, the message is printed to
both consoles.
Signed-off-by : Robin Getz <rgetz@blackfin.uclinux.org>
Cc: "Andrew Morton" <akpm@linux-foundation.org>
Cc: "Linus Torvalds" <torvalds@linux-foundation.org>
LKML-Reference: <200907091308.37370.rgetz@blackfin.uclinux.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The stat entries can be freed when the stat file is being read.
The worse is, the ptr can be freed immediately after it's returned
from workqueue_stat_start/next().
Add a refcnt to struct cpu_workqueue_stats to avoid use-after-free.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4A51B16F.6010608@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add stat_release() callback to struct tracer_stat, so a stat tracer
can release it's entries after the stat file has been read out.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A51B16A.6020708@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
So we have:
- kmemtrace_print_alloc/free() for kmemtrace default output
- kmemtrace_print_alloc/free_user() for binary output used
by kmemtrace-user.
Suggested-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A51B288.70505@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove the obsolete seq_print_ip_sym() usage and replace it
by the %pf format in order to print function symbols.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
LKML-Reference: <1247107590-6428-3-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove the obsolete seq_print_ip_sym() usage and replace it
by the %pf format in order to print function symbols.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <1247107590-6428-2-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove empty subsystem and its directory when module unload.
Before patch:
# rmmod trace-events-sample.ko
# ls sample
enable filter
After patch:
# rmmod trace-events-sample.ko
# ls sample
ls: cannot access sample: No such file or directory
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Acked-by: Tom Zanussi <tzanussi@gmail.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4A55A8BE.9010707@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
No need to save preds to event_subsystem, because it's not used.
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Acked-by: Tom Zanussi <tzanussi@gmail.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4A55A83C.1030005@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
init_rt_rq() initializes only rq->rt.pushable_tasks, and not the
pushable_tasks field of the passed rt_rq. The plist is not used
uninitialized since the only pushable_tasks plists used are the
ones of root rt_rqs; anyway reinitializing the list on every group
creation corrupts the root plist, losing its previous contents.
Signed-off-by: Fabio Checconi <fabio@gandalf.sssup.it>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090615185638.GK21741@gandalf.sssup.it>
CC: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The sched_stat fields are currently not reset upon fork.
Ingo's recent commit 6c594c21fc
did reset nr_migrations, but it didn't reset any of the
others.
This patch resets all sched_stat fields on fork.
Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <193b0f820907090457s7a3662f4gcdecdc22fcae857b@mail.gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fixes an easily triggerable BUG() when setting process affinities.
Make sure to count the number of migratable tasks in the same place:
the root rt_rq. Otherwise the number doesn't make sense and we'll hit
the BUG in set_cpus_allowed_rt().
Also, make sure we only count tasks, not groups (this is probably
already taken care of by the fact that rt_se->nr_cpus_allowed will be 0
for groups, but be more explicit)
Tested-by: Thomas Gleixner <tglx@linutronix.de>
CC: stable@kernel.org
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Gregory Haskins <ghaskins@novell.com>
LKML-Reference: <1247067476.9777.57.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Instead of open coding the unclone context thingy, put it in
a common function.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
kmemleak_alloc() calls were added in some places where alloc_bootmem was
called. Since now kmemleak tracks bootmem allocations, these explicit
calls should be run.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Commit 5fd29d6ccb ("printk: clean up
handling of log-levels and newlines") changed printk semantics. printk
lines with multiple KERN_<level> prefixes are no longer emitted as
before the patch.
<level> is now included in the output on each additional use.
Remove all uses of multiple KERN_<level>s in formats.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix various silly problems wrt mnt_namespace.h:
- exit_mnt_ns() isn't used, remove it
- done that, sched.h and nsproxy.h inclusions aren't needed
- mount.h inclusion was need for vfsmount_lock, but no longer
- remove mnt_namespace.h inclusion from files which don't use anything
from mnt_namespace.h
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch converts the ring buffers into a completely lockless
buffer recording system. The read side still takes locks since
we still serialize readers. But the writers are the ones that
must be lockless (those can happen in NMIs).
The main change is to the "head_page" pointer. We write to the
tail, and read from the head. The "head_page" pointer in the cpu
buffer is now just a reference to where to look. The real head
page is now kept in the head_page->list->prev->next pointer.
That is, in the list head of the previous page we set flags.
The list pages are allocated to be aligned such that the lowest
significant bits are always zero pointing to the list. This gives
us play to put in flags to their pointers.
bit 0: set when the page is a head page
bit 1: set when the writer is moving the page (for overwrite mode)
cmpxchg is used to update the pointer.
When the writer wraps the buffer and the tail meets the head,
in overwrite mode, the writer must move the head page forward.
It first uses cmpxchg to change the pointer flag from 1 to 2.
Once this is done, the reader on another CPU will not take the
page from the buffer.
The writers need to protect against interrupts (we don't bother with
disabling interrupts because NMIs are allowed to write too).
After the writer sets the pointer flag to 2, it takes care to
manage interrupts coming in. This is discribed in detail within the
comments of the code.
Changes in version 2:
- Let reader reset entries value of header page.
- Fix tail page passing commit page on reader page test.
- Always increment entries and write counter in rb_tail_page_update
- Add safety check in rb_set_commit_to_write to break out of infinite loop
- add mask in rb_is_reader_page
[ Impact: lock free writing to the ring buffer ]
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch changes the ring buffer data pages from using a link list
head pointer, to making each buffer page point to another buffer page
and never back to a "head".
This makes the handling of the ring buffer less complex, since the
traversing of the ring buffer pages no longer needs to account for the
head pointer.
This change also is needed to make the ring buffer lockless.
[
Changes in version 2:
- Added change that Lai Jiangshan mentioned.
From: Lai Jiangshan <laijs@cn.fujitsu.com>
Date: Thu, 11 Jun 2009 11:25:48 +0800
LKML-Reference: <4A30793C.6090208@cn.fujitsu.com>
I'm not sure whether these 4 lines:
bpage = list_entry(pages.next, struct buffer_page, list);
list_del_init(&bpage->list);
cpu_buffer->pages = &bpage->list;
list_splice(&pages, cpu_buffer->pages);
equal to these 2 lines:
cpu_buffer->pages = pages.next;
list_del(&pages);
If there are equivalent, I think the second one
are simpler. It may be not a really necessarily cleanup.
What I asked is: if there are equivalent, could you use these two line:
cpu_buffer->pages = pages.next;
list_del(&pages);
]
[ Impact: simplify the ring buffer to help make it lockless ]
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
The ktime_get() functions for GENERIC_TIME=n are still located in
hrtimer.c. Move them to time/timekeeping.c where they belong.
LKML-Reference: <new-submission>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The generic ktime_get function defined in kernel/hrtimer.c is suboptimial
for GENERIC_TIME=y:
0) | ktime_get() {
0) | ktime_get_ts() {
0) | getnstimeofday() {
0) | read_tod_clock() {
0) 0.601 us | }
0) 1.938 us | }
0) | set_normalized_timespec() {
0) 0.602 us | }
0) 4.375 us | }
0) 5.523 us | }
Overall there are two read_seqbegin/read_seqretry loops and a lot of
unnecessary struct timespec calculations. ktime_get returns a nano second
value which is the sum of xtime, wall_to_monotonic and the nano second
delta from the clock source.
ktime_get can be optimized for GENERIC_TIME=y. The new version only calls
clocksource_read:
0) | ktime_get() {
0) | read_tod_clock() {
0) 0.610 us | }
0) 1.977 us | }
It uses a single read_seqbegin/readseqretry loop and just adds everthing
to a nano second value.
ktime_get_ts is optimized in a similar fashion.
[ tglx: added WARN_ON(timekeeping_suspended) as in getnstimeofday() ]
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Acked-by: john stultz <johnstul@us.ibm.com>
LKML-Reference: <20090707112728.3005244d@skybase>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
do_execve() and ptrace_attach() return -EINTR if
mutex_lock_interruptible(->cred_guard_mutex) fails.
This is not right, change the code to return ERESTARTNOINTR.
Perhaps we should also change proc_pid_attr_write().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These warnings were observed on MIPS32 using 2.6.31-rc1 and gcc-4.2.0:
mm/page_alloc.c: In function 'alloc_pages_exact':
mm/page_alloc.c:1986: warning: passing argument 1 of 'virt_to_phys' makes pointer from integer without a cast
drivers/usb/mon/mon_bin.c: In function 'mon_alloc_buff':
drivers/usb/mon/mon_bin.c:1264: warning: passing argument 1 of 'virt_to_phys' makes pointer from integer without a cast
[akpm@linux-foundation.org: fix kernel/perf_counter.c too]
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The kerneldoc comment describing suspend_device_irqs() is currently
misleading, because generally the function doesn't really disable
interrupt lines at the chip level. Replace it with a more accurate
one.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
LKML-Reference: <200907050022.35117.rjw@sisk.pl>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
