Enable gcov profiling of the entire kernel on x86_64. Required changes
include disabling profiling for:
* arch/kernel/acpi/realmode and arch/kernel/boot/compressed:
not linked to main kernel
* arch/vdso, arch/kernel/vsyscall_64 and arch/kernel/hpet:
profiling causes segfaults during boot (incompatible context)
Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Li Wei <W.Li@Sun.COM>
Cc: Michael Ellerman <michaele@au1.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Heiko Carstens <heicars2@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <mschwid2@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Enable the use of GCC's coverage testing tool gcov [1] with the Linux
kernel. gcov may be useful for:
* debugging (has this code been reached at all?)
* test improvement (how do I change my test to cover these lines?)
* minimizing kernel configurations (do I need this option if the
associated code is never run?)
The profiling patch incorporates the following changes:
* change kbuild to include profiling flags
* provide functions needed by profiling code
* present profiling data as files in debugfs
Note that on some architectures, enabling gcc's profiling option
"-fprofile-arcs" for the entire kernel may trigger compile/link/
run-time problems, some of which are caused by toolchain bugs and
others which require adjustment of architecture code.
For this reason profiling the entire kernel is initially restricted
to those architectures for which it is known to work without changes.
This restriction can be lifted once an architecture has been tested
and found compatible with gcc's profiling. Profiling of single files
or directories is still available on all platforms (see config help
text).
[1] http://gcc.gnu.org/onlinedocs/gcc/Gcov.html
Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Li Wei <W.Li@Sun.COM>
Cc: Michael Ellerman <michaele@au1.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Heiko Carstens <heicars2@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <mschwid2@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Call constructors (gcc-generated initcall-like functions) during kernel
start and module load. Constructors are e.g. used for gcov data
initialization.
Disable constructor support for usermode Linux to prevent conflicts with
host glibc.
Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Li Wei <W.Li@Sun.COM>
Cc: Michael Ellerman <michaele@au1.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Heiko Carstens <heicars2@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <mschwid2@linux.vnet.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
clone_nsproxy() does useless copying of old nsproxy -- every pointer will
be rewritten to new ns or to old ns. Remove copying, rename
clone_nsproxy(), create_nsproxy() will be used by C/R code to create fresh
nsproxy on restart.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
create_uts_ns() will be used by C/R to create fresh uts_ns.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
copy_pid_ns() is a perfect example of a case where unwinding leads to more
code and makes it less clear. Watch the diffstat.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
create_pid_namespace() creates everything, but caller has to assign parent
pidns by hand, which is unnatural. At the moment of call new ->level has
to be taken from somewhere and parent pidns is already available.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
find_task_by_pid_type_ns is only used to implement find_task_by_vpid and
find_task_by_pid_ns, but both of them pass PIDTYPE_PID as first argument.
So just fold find_task_by_pid_type_ns into find_task_by_pid_ns and use
find_task_by_pid_ns to implement find_task_by_vpid.
While we're at it also remove the exports for find_task_by_pid_ns and
find_task_by_vpid - we don't have any modular callers left as the only
modular caller of he old pre pid namespace find_task_by_pid (gfs2) was
switched to pid_task which operates on a struct pid pointer instead of a
pid_t. Given the confusion about pid_t values vs namespace that's
generally the better option anyway and I think we're better of restricting
modules to do it that way.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remoce the unused variable 'val' from __do_proc_dointvec()
The integer has been declared and used as 'val = -val' and there is no
reference to it anywhere.
Signed-off-by: Sukanto Ghosh <sukanto.cse.iitb@gmail.com>
Cc: Jaswinder Singh Rajput <jaswinder@kernel.org>
Cc: Sukanto Ghosh <sukanto.cse.iitb@gmail.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that kthread_stop() can be used even if the task has already exited,
we can kill the "wait_to_die:" loop in migration_thread(). But we must
pin rq->migration_thread after creation.
Actually, I don't think CPU_UP_CANCELED or CPU_DEAD should wait for
->migration_thread exit. Perhaps we can simplify this code a bit more.
migration_call() can set ->should_stop and forget about this thread. But
we need a new helper in kthred.c for that.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Vitaliy Gusev <vgusev@openvz.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Based on Eric's patch which in turn was based on my patch.
kthread_stop() has the nasty problems:
- it runs unpredictably long with the global semaphore held.
- it deadlocks if kthread itself does kthread_stop() before it obeys
the kthread_should_stop() request.
- it is not useable if kthread exits on its own, see for example the
ugly "wait_to_die:" hack in migration_thread()
- it is not possible to just tell kthread it should stop, we must always
wait for its exit.
With this patch kthread() allocates all neccesary data (struct kthread) on
its own stack, globals kthread_stop_xxx are deleted. ->vfork_done is used
as a pointer into "struct kthread", this means kthread_stop() can easily
wait for kthread's exit.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Vitaliy Gusev <vgusev@openvz.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We use two completions two create the kernel thread, this is a bit ugly.
kthread() wakes up create_kthread() via ->started, then create_kthread()
wakes up the caller kthread_create() via ->done. But kthread() does not
need to wait for kthread(), it can just return. Instead kthread() itself
can wake up the caller of kthread_create().
Kill kthread_create_info->started, ->done is enough. This improves the
scalability a bit and sijmplifies the code.
The only problem if kernel_thread() fails, in that case create_kthread()
must do complete(&create->done).
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Vitaliy Gusev <vgusev@openvz.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
do_wait:
current->state = TASK_INTERRUPTIBLE;
read_lock(&tasklist_lock);
... search for the task to reap ...
In theory, the ->state changing can leak into the critical section. Since
the child can change its status under read_lock(tasklist) in parallel
(finish_stop/ptrace_stop), we can miss the wakeup if __wake_up_parent()
sees us in TASK_RUNNING state. Add the barrier.
Also, use __set_current_state() to set TASK_RUNNING.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
do_wait() does BUG_ON(tsk->signal != current->signal), this looks like a
raher obsolete check. At least, I don't think do_wait() is the best place
to verify that all threads have the same ->signal. Remove it.
Also, change the code to use while_each_thread().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that we don't pass &retval down to other helpers we can simplify
the code more.
- kill tsk_result, just use retval
- add the "notask" label right after the main loop, and
s/got end/goto notask/ after the fastpath pid check.
This way we don't need to initialize retval before this
check and the code becomes a bit more clean, if this pid
has no attached tasks we should just skip the list search.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce "struct wait_opts" which holds the parameters for misc helpers
in do_wait() pathes.
This adds 13 lines to kernel/exit.c, but saves 256 bytes from .o and imho
makes the code much more readable.
This patch temporary uglifies rusage/siginfo code a little bit, will be
addressed by further cleanups.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
No functional changes, preparation for the next patch.
ptrace_do_wait() adds WUNTRACED to options for wait_task_stopped() which
should always accept the stopped tracee, even if do_wait() was called
without WUNTRACED.
Change wait_task_stopped() to check "ptrace || WUNTRACED" instead. This
makes the code more explicit, and "int options" argument becomes const in
do_wait() pathes.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The forked child can have TIF_SIGPENDING if it was copied from parent's
ti->flags. But this is harmless and actually almost never happens,
because copy_process() can't succeed if signal_pending() == T.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is no reason for thread_group_cputime() in wait_task_zombie(), there
must be no other threads.
This call was previously needed to collect the per-cpu data which we do
not have any longer.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Vitaly Mayatskikh <vmayatsk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change ptrace_getsiginfo/ptrace_setsiginfo to use lock_task_sighand()
without tasklist_lock. Perhaps it makes sense to make a single helper
with "bool rw" argument.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If the non-traced sub-thread calls do_notify_parent_cldstop(), we send the
notification to group_leader->real_parent and we report group_leader's
pid.
But, if group_leader is traced we use the wrong ->parent->nsproxy->pid_ns,
the tracer and parent can live in different namespaces. Change the code
to use "parent" instead of tsk->parent.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Acked-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change wait_task_zombie() to use ->real_parent instead of ->parent. We
could even use current afaics, but ->real_parent is more clean.
We know that the child is not ptrace_reparented() and thus they are equal.
But we should avoid using task_struct->parent, we are going to remove it.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Use rcu_read_lock() instead of tasklist_lock to find/get the task
in ptrace_get_task_struct().
- Make it static, it has no callers outside of ptrace.c.
- The comment doesn't match the reality, this helper does not do
any checks. Beacuse it is really trivial and static I removed the
whole comment.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the "Nasty, nasty" lock dance in ptrace_attach()/ptrace_traceme() -
from now task_lock() has nothing to do with ptrace at all.
With the recent changes nobody uses task_lock() to serialize with ptrace,
but in fact it was never needed and it was never used consistently.
However ptrace_attach() calls __ptrace_may_access() and needs task_lock()
to pin task->mm for get_dumpable(). But we can call __ptrace_may_access()
before we take tasklist_lock, ->cred_exec_mutex protects us against
do_execve() path which can change creds and MMF_DUMP* flags.
(ugly, but we can't use ptrace_may_access() because it hides the error
code, so we have to take task_lock() and use __ptrace_may_access()).
NOTE: this change assumes that LSM hooks, security_ptrace_may_access() and
security_ptrace_traceme(), can be called without task_lock() held.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ptrace_attach() and ptrace_traceme() are the last functions which look as
if the untraced task can have task->ptrace != 0, this must not be
possible. Change the code to just check ->ptrace != 0 and s/|=/=/ to set
PT_PTRACED.
Also, a couple of trivial whitespace cleanups in ptrace_attach().
And move ptrace_traceme() up near ptrace_attach() to keep them close to
each other.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Add PF_KTHREAD check to prevent attaching to the kernel thread
with a borrowed ->mm.
With or without this change we can race with daemonize() which
can set PF_KTHREAD or clear ->mm after ptrace_attach() does the
check, but this doesn't matter because reparent_to_kthreadd()
does ptrace_unlink().
- Kill "!task->mm" check. We don't really care about ->mm != NULL,
and the task can call exit_mm() right after we drop task_lock().
What we need is to make sure we can't attach after exit_notify(),
check task->exit_state != 0 instead.
Also, move the "already traced" check down for cosmetic reasons.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
No functional changes.
- Nobody except ptrace.c & co should use ptrace flags directly, we have
task_ptrace() for that.
- No need to specially check PT_PTRACED, we must not have other PT_ bits
set without PT_PTRACED. And no need to know this flag exists.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
"Search in the siblings" should use ->real_parent, not ->parent. If the
task is traced then ->parent == tracer, while the task's parent is always
->real_parent.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
allow_signal() checks ->mm == NULL. Not sure why. Perhaps to make sure
current is the kernel thread. But this helper must not be used unless we
are the kernel thread, kill this check.
Also, document the fact that the CLONE_SIGHAND kthread must not use
allow_signal(), unless the caller really wants to change the parent's
->sighand->action as well.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We don't have an interface to reset mem.limit or memsw.limit now.
This patch allows to reset mem.limit or memsw.limit when they are being
set to -1.
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The 'noprefix' option was introduced for backwards-compatibility of
cpuset, but actually it can be used when mounting other subsystems.
This results in possibility of name collision, and now the collision can
really happen, because we have 'stat' file in both memory and cpuacct
subsystem:
# mount -t cgroup -o noprefix,memory,cpuacct xxx /mnt
Cgroup will happily mount the 2 subsystems, but only 'stat' file of memory
subsys can be seen.
We don't want users to use nopreifx, and also want to avoid name
collision, so we change to allow noprefix only if mounting just the cpuset
subsystem.
[akpm@linux-foundation.org: fix shift for cpuset_subsys_id >= 32]
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Statistics for softirq doesn't exist.
It will be helpful like statistics for interrupts.
This patch introduces counting the number of softirq,
which will be exported in /proc/softirqs.
When softirq handler consumes much CPU time,
/proc/stat is like the following.
$ while :; do cat /proc/stat | head -n1 ; sleep 10 ; done
cpu 88 0 408 739665 583 28 2 0 0
cpu 450 0 1090 740970 594 28 1294 0 0
^^^^
softirq
In such a situation,
/proc/softirqs shows us which softirq handler is invoked.
We can see the increase rate of softirqs.
<before>
$ cat /proc/softirqs
CPU0 CPU1 CPU2 CPU3
HI 0 0 0 0
TIMER 462850 462805 462782 462718
NET_TX 0 0 0 365
NET_RX 2472 2 2 40
BLOCK 0 0 381 1164
TASKLET 0 0 0 224
SCHED 462654 462689 462698 462427
RCU 3046 2423 3367 3173
<after>
$ cat /proc/softirqs
CPU0 CPU1 CPU2 CPU3
HI 0 0 0 0
TIMER 463361 465077 465056 464991
NET_TX 53 0 1 365
NET_RX 3757 2 2 40
BLOCK 0 0 398 1170
TASKLET 0 0 0 224
SCHED 463074 464318 464612 463330
RCU 3505 2948 3947 3673
When CPU TIME of softirq is high,
the rates of increase is the following.
TIMER : 220/sec : CPU1-3
NET_TX : 5/sec : CPU0
NET_RX : 120/sec : CPU0
SCHED : 40-200/sec : all CPU
RCU : 45-58/sec : all CPU
The rates of increase in an idle mode is the following.
TIMER : 250/sec
SCHED : 250/sec
RCU : 2/sec
It seems many softirqs for receiving packets and rcu are invoked. This
gives us help for checking system.
Signed-off-by: Keika Kobayashi <kobayashi.kk@ncos.nec.co.jp>
Reviewed-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Round the slow work queue's cull and OOM timeouts to whole second boundary
with round_jiffies(). The slow work queue uses a pair of timers to cull
idle threads and, after OOM, to delay new thread creation.
This patch also extracts the mod_timer() logic for the cull timer into a
separate helper function.
By rounding non-time-critical timers such as these to whole seconds, they
will be batched up to fire at the same time rather than being spread out.
This allows the CPU wake up less, which saves power.
Signed-off-by: Chris Peterson <cpeterso@cpeterso.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move supplementary groups implementation to kernel/groups.c .
kernel/sys.c already accumulated quite a few random stuff.
Do strictly copy/paste + add required headers to compile. Compile-tested
on many configs and archs.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, the following scenario appears to be possible in theory:
* Tasks are frozen for hibernation or suspend.
* Free pages are almost exhausted.
* Certain piece of code in the suspend code path attempts to allocate
some memory using GFP_KERNEL and allocation order less than or
equal to PAGE_ALLOC_COSTLY_ORDER.
* __alloc_pages_internal() cannot find a free page so it invokes the
OOM killer.
* The OOM killer attempts to kill a task, but the task is frozen, so
it doesn't die immediately.
* __alloc_pages_internal() jumps to 'restart', unsuccessfully tries
to find a free page and invokes the OOM killer.
* No progress can be made.
Although it is now hard to trigger during hibernation due to the memory
shrinking carried out by the hibernation code, it is theoretically
possible to trigger during suspend after the memory shrinking has been
removed from that code path. Moreover, since memory allocations are
going to be used for the hibernation memory shrinking, it will be even
more likely to happen during hibernation.
To prevent it from happening, introduce the oom_killer_disabled switch
that will cause __alloc_pages_internal() to fail in the situations in
which the OOM killer would have been called and make the freezer set
this switch after tasks have been successfully frozen.
[akpm@linux-foundation.org: be nicer to the namespace]
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Fengguang Wu <fengguang.wu@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Callers of alloc_pages_node() can optionally specify -1 as a node to mean
"allocate from the current node". However, a number of the callers in
fast paths know for a fact their node is valid. To avoid a comparison and
branch, this patch adds alloc_pages_exact_node() that only checks the nid
with VM_BUG_ON(). Callers that know their node is valid are then
converted.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Paul Mundt <lethal@linux-sh.org> [for the SLOB NUMA bits]
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix allocating page cache/slab object on the unallowed node when memory
spread is set by updating tasks' mems_allowed after its cpuset's mems is
changed.
In order to update tasks' mems_allowed in time, we must modify the code of
memory policy. Because the memory policy is applied in the process's
context originally. After applying this patch, one task directly
manipulates anothers mems_allowed, and we use alloc_lock in the
task_struct to protect mems_allowed and memory policy of the task.
But in the fast path, we didn't use lock to protect them, because adding a
lock may lead to performance regression. But if we don't add a lock,the
task might see no nodes when changing cpuset's mems_allowed to some
non-overlapping set. In order to avoid it, we set all new allowed nodes,
then clear newly disallowed ones.
[lee.schermerhorn@hp.com:
The rework of mpol_new() to extract the adjusting of the node mask to
apply cpuset and mpol flags "context" breaks set_mempolicy() and mbind()
with MPOL_PREFERRED and a NULL nodemask--i.e., explicit local
allocation. Fix this by adding the check for MPOL_PREFERRED and empty
node mask to mpol_new_mpolicy().
Remove the now unneeded 'nodes = NULL' from mpol_new().
Note that mpol_new_mempolicy() is always called with a non-NULL
'nodes' parameter now that it has been removed from mpol_new().
Therefore, we don't need to test nodes for NULL before testing it for
'empty'. However, just to be extra paranoid, add a VM_BUG_ON() to
verify this assumption.]
[lee.schermerhorn@hp.com:
I don't think the function name 'mpol_new_mempolicy' is descriptive
enough to differentiate it from mpol_new().
This function applies cpuset set context, usually constraining nodes
to those allowed by the cpuset. However, when the 'RELATIVE_NODES flag
is set, it also translates the nodes. So I settled on
'mpol_set_nodemask()', because the comment block for mpol_new() mentions
that we need to call this function to "set nodes".
Some additional minor line length, whitespace and typo cleanup.]
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Paul Menage <menage@google.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix the bug that the kernel didn't spread page cache/slab object evenly
over all the allowed nodes when spread flags were set by updating tasks'
page/slab spread flags in time.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Paul Menage <menage@google.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The kernel still allocates the page caches on old node after modifying its
cpuset's mems when 'memory_spread_page' was set, or it didn't spread the
page cache evenly over all the nodes that faulting task is allowed to usr
after memory_spread_page was set. it is caused by the old mem_allowed and
flags of the task, the current kernel doesn't updates them unless some
function invokes cpuset_update_task_memory_state(), it is too late
sometimes.We must update the mem_allowed and the flags of the tasks in
time.
Slab has the same problem.
The following patches fix this bug by updating tasks' mem_allowed and
spread flag after its cpuset's mems or spread flag is changed.
This patch:
Extract a function from cpuset_update_task_memory_state(). It will be
used later for update tasks' page/slab spread flags after its cpuset's
flag is set
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Paul Menage <menage@google.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Several WARN_ON() messages omit the '\n' at the end of the string, which
is a simple (and understandable) error. The next line printed after
that warning line is usually the current module list, and that printk
does not have a log-level marker - resulting in one long mixed-up line.
Adding this loglevel marker will now avoid this unreadable mess.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This adds a KERN_DEFAULT loglevel marker, for when you cannot decide
which loglevel you want, and just want to keep an existing printk
with the default loglevel.
The difference between having KERN_DEFAULT and having no log-level
marker at all is two-fold:
- having the log-level marker will now force a new-line if the
previous printout had not added one (perhaps because it forgot,
but perhaps because it expected a continuation)
- having a log-level marker is required if you are printing out a
message that otherwise itself could perhaps otherwise be mistaken
for a log-level.
Signed-of-by: Linus Torvalds <torvalds@linux-foundation.org>
It used to be that we would only look at the log-level in a printk()
after explicit newlines, which can cause annoying problems when the
previous printk() did not end with a '\n'. In that case, the log-level
marker would be just printed out in the middle of the line, and be
seen as just noise rather than change the logging level.
This changes things to always look at the log-level in the first
bytes of the printout. If a log level marker is found, it is always
used as the log-level. Additionally, if no newline existed, one is
added (unless the log-level is the explicit KERN_CONT marker, to
explicitly show that it's a continuation of a previous line).
Acked-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Many developers use "/debug/" or "/debugfs/" or "/sys/kernel/debug/"
directory name to mount debugfs filesystem for ftrace according to
./Documentation/tracers/ftrace.txt file.
And, three directory names(ex:/debug/, /debugfs/, /sys/kernel/debug/) is
existed in kernel source like ftrace, DRM, Wireless, Documentation,
Network[sky2]files to mount debugfs filesystem.
debugfs means debug filesystem for debugging easy to use by greg kroah
hartman. "/sys/kernel/debug/" name is suitable as directory name
of debugfs filesystem.
- debugfs related reference: http://lwn.net/Articles/334546/
Fix inconsistency of directory name to mount debugfs filesystem.
* From Steven Rostedt
- find_debugfs() and tracing_files() in this patch.
Signed-off-by: GeunSik Lim <geunsik.lim@samsung.com>
Acked-by : Inaky Perez-Gonzalez <inaky@linux.intel.com>
Reviewed-by : Steven Rostedt <rostedt@goodmis.org>
Reviewed-by : James Smart <james.smart@emulex.com>
CC: Jiri Kosina <trivial@kernel.org>
CC: David Airlie <airlied@linux.ie>
CC: Peter Osterlund <petero2@telia.com>
CC: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
CC: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
CC: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
During bootup performance tracing we see repeated occurrences of
/sys/kernel/uid/* events for the same uid, leading to a,
in this case, rather pointless userspace processing for the
same uid over and over.
This is usually caused by tools which change their uid to "nobody",
to run without privileges to read data supplied by untrusted users.
This change delays the execution of the (already existing) scheduled
work, to cleanup the uid after one second, so the allocated and announced
uid can possibly be re-used by another process.
This is the current behavior, where almost every invocation of a
binary, which changes the uid, creates two events:
$ read START < /sys/kernel/uevent_seqnum; \
for i in `seq 100`; do su --shell=/bin/true bin; done; \
read END < /sys/kernel/uevent_seqnum; \
echo $(($END - $START))
178
With the delayed cleanup, we get only two events, and userspace finishes
a bit faster too:
$ read START < /sys/kernel/uevent_seqnum; \
for i in `seq 100`; do su --shell=/bin/true bin; done; \
read END < /sys/kernel/uevent_seqnum; \
echo $(($END - $START))
1
Acked-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This false positive is due to field padding in struct sigqueue. When
this dynamically allocated structure is copied to the stack (in arch-
specific delivery code), kmemcheck sees a read from the padding, which
is, naturally, uninitialized.
Hide the false positive using the __GFP_NOTRACK_FALSE_POSITIVE flag.
Also made the rlimit override code a bit clearer by introducing a new
variable.
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
This gets rid of a heap of false-positive warnings from the tracer
code due to the use of bitfields.
[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
With kmemcheck enabled, the slab allocator needs to do this:
1. Tell kmemcheck to allocate the shadow memory which stores the status of
each byte in the allocation proper, e.g. whether it is initialized or
uninitialized.
2. Tell kmemcheck which parts of memory that should be marked uninitialized.
There are actually a few more states, such as "not yet allocated" and
"recently freed".
If a slab cache is set up using the SLAB_NOTRACK flag, it will never return
memory that can take page faults because of kmemcheck.
If a slab cache is NOT set up using the SLAB_NOTRACK flag, callers can still
request memory with the __GFP_NOTRACK flag. This does not prevent the page
faults from occuring, however, but marks the object in question as being
initialized so that no warnings will ever be produced for this object.
In addition to (and in contrast to) __GFP_NOTRACK, the
__GFP_NOTRACK_FALSE_POSITIVE flag indicates that the allocation should
not be tracked _because_ it would produce a false positive. Their values
are identical, but need not be so in the future (for example, we could now
enable/disable false positives with a config option).
Parts of this patch were contributed by Pekka Enberg but merged for
atomicity.
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Peter Oberparleiter