26 Jul, 2008
40 commits
-
schedule_on_each_cpu() can use schedule_work_on() to avoid the code
duplication.Signed-off-by: Oleg Nesterov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
queue_work() can use queue_work_on() to avoid the code duplication.
Signed-off-by: Oleg Nesterov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add lockdep annotations to flush_work() and update the comment.
Signed-off-by: Oleg Nesterov
Cc: Jarek Poplawski
Acked-by: Johannes Berg
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Now that it is safe to use get_online_cpus() we can revert
[S390] cpu topology: Fix possible deadlock.
commit: fd781fa25c9e9c6fd1599df060b05e7c4ad724e5and call arch_reinit_sched_domains() directly from topology_work_fn().
Signed-off-by: Oleg Nesterov
Cc: Gautham R Shenoy
Tested-by: Heiko Carstens
Cc: Max Krasnyansky
Cc: Paul Jackson
Cc: Paul Menage
Cc: Peter Zijlstra
Cc: Vegard Nossum
Cc: Martin Schwidefsky
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
workqueue_cpu_callback(CPU_DEAD) flushes cwq->thread under
cpu_maps_update_begin(). This means that the multithreaded workqueues
can't use get_online_cpus() due to the possible deadlock, very bad and
very old problem.Introduce the new state, CPU_POST_DEAD, which is called after
cpu_hotplug_done() but before cpu_maps_update_done().Change workqueue_cpu_callback() to use CPU_POST_DEAD instead of CPU_DEAD.
This means that create/destroy functions can't rely on get_online_cpus()
any longer and should take cpu_add_remove_lock instead.[akpm@linux-foundation.org: fix CONFIG_SMP=n]
Signed-off-by: Oleg Nesterov
Acked-by: Gautham R Shenoy
Cc: Heiko Carstens
Cc: Max Krasnyansky
Cc: Paul Jackson
Cc: Paul Menage
Cc: Peter Zijlstra
Cc: Vegard Nossum
Cc: Martin Schwidefsky
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Change schedule_on_each_cpu() to use flush_work() instead of
flush_workqueue(), this way we don't wait for other work_struct's which
can be queued meanwhile.Signed-off-by: Oleg Nesterov
Cc: Jarek Poplawski
Cc: Max Krasnyansky
Cc: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Most of users of flush_workqueue() can be changed to use cancel_work_sync(),
but sometimes we really need to wait for the completion and cancelling is not
an option. schedule_on_each_cpu() is good example.Add the new helper, flush_work(work), which waits for the completion of the
specific work_struct. More precisely, it "flushes" the result of of the last
queue_work() which is visible to the caller.For example, this code
queue_work(wq, work);
/* WINDOW */
queue_work(wq, work);flush_work(work);
doesn't necessary work "as expected". What can happen in the WINDOW above is
- wq starts the execution of work->func()
- the caller migrates to another CPU
now, after the 2nd queue_work() this work is active on the previous CPU, and
at the same time it is queued on another. In this case flush_work(work) may
return before the first work->func() completes.It is trivial to add another helper
int flush_work_sync(struct work_struct *work)
{
return flush_work(work) || wait_on_work(work);
}which works "more correctly", but it has to iterate over all CPUs and thus
it much slower than flush_work().Signed-off-by: Oleg Nesterov
Acked-by: Max Krasnyansky
Acked-by: Jarek Poplawski
Cc: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
insert_work() inserts the new work_struct before or after cwq->worklist,
depending on the "int tail" parameter. Change it to accept "list_head *"
instead, this shrinks .text a bit and allows us to insert the barrier
after specific work_struct.Signed-off-by: Oleg Nesterov
Cc: Jarek Poplawski
Cc: Max Krasnyansky
Cc: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
I don't understand why the multi-thread coredump implies the core_uses_pid
behaviour, but we shouldn't use mm->mm_users for that. This counter can
be incremented by get_task_mm(). Use the valued returned by
coredump_wait() instead.Also, remove the "const char *pattern" argument, format_corename() can use
core_pattern directly.[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Oleg Nesterov
Cc: Roland McGrath
Cc: Alan Cox
Cc: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Now that we have core_state->dumper list we can use it to wake up the
sub-threads waiting for the coredump completion.This uglifies the code and .text grows by 47 bytes, but otoh mm_struct
lessens by sizeof(struct completion). Also, with this change we can
decouple exit_mm() from the coredumping code.Signed-off-by: Oleg Nesterov
Cc: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Kill the nasty rcu_read_lock() + do_each_thread() loop, use the list
encoded in mm->core_state instead, s/GFP_ATOMIC/GFP_KERNEL/.This patch allows futher cleanups in binfmt_elf_fdpic.c.
Signed-off-by: Oleg Nesterov
Acked-by: Roland McGrath
Cc: David Howells
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Kill the nasty rcu_read_lock() + do_each_thread() loop, use the list
encoded in mm->core_state instead, s/GFP_ATOMIC/GFP_KERNEL/.This patch allows futher cleanups in binfmt_elf.c, in particular we can
kill the parallel info->threads list.Signed-off-by: Oleg Nesterov
Acked-by: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
binfmt->core_dump() has to iterate over the all threads in system in order
to find the coredumping threads and construct the list using the
GFP_ATOMIC allocations.With this patch each thread allocates the list node on exit_mm()'s stack and
adds itself to the list.This allows us to do further changes:
- simplify ->core_dump()
- change exit_mm() to clear ->mm first, then wait for ->core_done.
this makes the coredumping process visible to oom_kill- kill mm->core_done
Signed-off-by: Oleg Nesterov
Acked-by: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Move the "struct core_state core_state" from coredump_wait() to
do_coredump(), this makes mm->core_state visible to binfmt->core_dump().Signed-off-by: Oleg Nesterov
Acked-by: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Turn core_state->nr_threads into atomic_t and kill now unneeded
down_write(&mm->mmap_sem) in exit_mm().Signed-off-by: Oleg Nesterov
Cc: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Change zap_process() to return int instead of incrementing
mm->core_state->nr_threads directly. Change zap_threads() to set
mm->core_state only on success.This patch restores the original size of .text, and more importantly now
->nr_threads is used in two places only.Signed-off-by: Oleg Nesterov
Cc: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Move mm->core_waiters into "struct core_state" allocated on stack. This
shrinks mm_struct a little bit and allows further changes.This patch mostly does s/core_waiters/core_state. The only essential
change is that coredump_wait() must clear mm->core_state before return.The coredump_wait()'s path is uglified and .text grows by 30 bytes, this
is fixed by the next patch.Signed-off-by: Oleg Nesterov
Cc: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
mm->core_startup_done points to "struct completion startup_done" allocated
on the coredump_wait()'s stack. Introduce the new structure, core_state,
which holds this "struct completion". This way we can add more info
visible to the threads participating in coredump without enlarging
mm_struct.No changes in affected .o files.
Signed-off-by: Oleg Nesterov
Cc: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
linux_binfmt->core_dump() runs before the process does exit_aio(), this
means that we can hit the kernel thread which shares the same ->mm.
Afaics, nothing really bad can happen, but perhaps it makes sense to fix
this minor bug.It is sad we have to iterate over all threads in system and use
GFP_ATOMIC. Hopefully we can kill theses ugly do_each_thread()s, but this
needs some nontrivial changes in mm_struct and do_coredump.Signed-off-by: Oleg Nesterov
Cc: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The main loop in zap_threads() must skip kthreads which may use the same
mm. Otherwise we "kill" this thread erroneously (for example, it can not
fork or exec after that), and the coredumping task stucks in the
TASK_UNINTERRUPTIBLE state forever because of the wrong ->core_waiters
count.Signed-off-by: Oleg Nesterov
Cc: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Kill PF_BORROWED_MM. Change use_mm/unuse_mm to not play with ->flags, and
do s/PF_BORROWED_MM/PF_KTHREAD/ for a couple of other users.No functional changes yet. But this allows us to do further
fixes/cleanups.oom_kill/ptrace/etc often check "p->mm != NULL" to filter out the
kthreads, this is wrong because of use_mm(). The problem with
PF_BORROWED_MM is that we need task_lock() to avoid races. With this
patch we can check PF_KTHREAD directly, or use a simple lockless helper:/* The result must not be dereferenced !!! */
struct mm_struct *__get_task_mm(struct task_struct *tsk)
{
if (tsk->flags & PF_KTHREAD)
return NULL;
return tsk->mm;
}Note also ecard_task(). It runs with ->mm != NULL, but it's the kernel
thread without PF_BORROWED_MM.Signed-off-by: Oleg Nesterov
Cc: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Introduce the new PF_KTHREAD flag to mark the kernel threads. It is set
by INIT_TASK() and copied to the forked childs (we could set it in
kthreadd() along with PF_NOFREEZE instead).daemonize() was changed as well. In that case testing of PF_KTHREAD is
racy, but daemonize() is hopeless anyway.This flag is cleared in do_execve(), before search_binary_handler().
Probably not the best place, we can do this in exec_mmap() or in
start_thread(), or clear it along with PF_FORKNOEXEC. But I think this
doesn't matter in practice, and if do_execve() fails kthread should die
soon.Signed-off-by: Oleg Nesterov
Cc: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
1. SIGKILL can't be blocked, remove this check from sigkill_pending().
2. When ptrace_stop() sees sigkill_pending() == T, it can just return.
Kill "int killed" and simplify the code. This also is more correct,
the tracer shouldn't see us in TASK_TRACED if we are not going to
stop.I strongly believe this code needs further changes. We should do the "was
this task killed" check unconditionally, currently it depends on
arch_ptrace_stop_needed(). On the other hand, sigkill_pending() isn't
very clever. If the task was killed tkill(SIGKILL), the signal can be
already dequeued if the caller is do_exit().Signed-off-by: Oleg Nesterov
Cc: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
ptrace_stop() has some complicated checks to prevent the scheduling in the
TASK_TRACED state with the pending SIGKILL, but these checks are racy, and
they depend on arch_ptrace_stop_needed().This patch assumes that the traced task should die asap if it was killed by
SIGKILL, in that case schedule()->signal_pending_state() has no reason to
ignore the TASK_WAKEKILL part of TASK_TRACED, and we can kill this nasty
special case.Note: do_exit()->ptrace_notify() is special, the killed task can already
dequeue SIGKILL at this point. Another indication that fatal_signal_pending()
is not exactly right.Signed-off-by: Oleg Nesterov
Cc: Ingo Molnar
Cc: Matthew Wilcox
Cc: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This patch contains the following cleanups for the asm/ptrace.h
userspace headers:- include/asm-generic/Kbuild.asm already lists ptrace.h, remove
the superfluous listings in the Kbuild files of the following
architectures:
- cris
- frv
- powerpc
- x86
- don't expose function prototypes and macros to userspace:
- arm
- blackfin
- cris
- mn10300
- parisc
- remove #ifdef CONFIG_'s around #define's:
- blackfin
- m68knommu
- sh: AFAIK __SH5__ should work in both kernel and userspace,
no need to leak CONFIG_SUPERH64 to userspace
- xtensa: cosmetical change to remove empty
#ifndef __ASSEMBLY__ #else #endif
from the userspace headersNot changed by this patch is the fact that the following architectures
have a different struct pt_regs depending on CONFIG_ variables:
- h8300
- m68knommu
- mipsThis does not work in userspace.
Signed-off-by: Adrian Bunk
Cc:
Cc: Roland McGrath
Cc: Oleg Nesterov
Acked-by: Greg Ungerer
Acked-by: Paul Mundt
Acked-by: Grant Grundler
Acked-by: Jesper Nilsson
Acked-by: Chris Zankel
Acked-by: David Howells
Acked-by: Paul Mackerras
Acked-by: Russell King
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Change the type of pid and tgid variables from int to the POSIX type
pid_t.Signed-off-by: Gustavo F. Padovan
Cc: Oleg Nesterov
Cc: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
In the switch to configurable HZ in 2.6, the treatment of the si_utime and
si_stime fields that are exposed to userland via the siginfo structure
looks to have been botched. As things stand, these fields report times in
units of HZ, so that userland gets information that varies depending on
the HZ that the kernel was configured with. This patch changes the
reported values to use USER_HZ units.Signed-off-by: Michael Kerrisk
Acked-by: Oleg Nesterov
Cc: Thomas Gleixner
Cc: Ingo Molnar
Cc: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
No changes in fs/exec.o
The for_each_process() loop in zap_threads() is very subtle, it is not
clear why we don't race with fork/exit/exec. Add the fat comment.Also, change the code to use while_each_thread().
Signed-off-by: Oleg Nesterov
Acked-by: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
fae5fa44f1fd079ffbed8e0add929dd7bbd1347f changed do_signal_stop() to check
SIGNAL_UNKILLABLE, this wasn't needed. If signal_group_exit() == F, the
signal sent to SIGNAL_UNKILLABLE task must be already filtered out by the
caller, get_signal_to_deliver(). And if signal_group_exit() == T we are
not going to stop.Signed-off-by: Oleg Nesterov
Acked-by: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
dequeue_signal() checks SIGNAL_GROUP_EXIT before setting
SIGNAL_STOP_DEQUEUED. This was added by
788e05a67c343fa22f2ae1d3ca264e7f15c25eaf a long ago to avoid the
coredump/SIGSTOP race.Since then the related code was changed, and now this subtle check is both
incomplete and unneeded at the same time. It is incomplete because
nowadays exec() doesn't set SIGNAL_GROUP_EXIT, so in fact we should check
signal_group_exit() to avoid a similar race. Fortunately, we doesn't need
the check at all. The only function which relies on SIGNAL_STOP_DEQUEUED
is do_signal_stop(), and it ignores this flag if signal_group_exit() == T,
this covers the SIGNAL_GROUP_EXIT case.Signed-off-by: Oleg Nesterov
Acked-by: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
There is no reason for rcu_read_lock() in __exit_signal(). tsk->sighand
can only be changed if tsk does exec, obviously this is not possible.Signed-off-by: Oleg Nesterov
Cc: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
With the recent changes collect_signal() always returns true. Change it
to return void and update the single caller.Signed-off-by: Oleg Nesterov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Factor out sigdelset() calls and remove the "still_pending" variable.
Signed-off-by: Oleg Nesterov
Acked-by: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
collect_signal() checks sigismember(&list->signal, sig), this is not
needed. This "sig" was just found by next_signal(), so it must be valid.We have a (completely broken) call to ->notifier in between, but it must
not play with sigpending->signal bits or unlock ->siglock.Signed-off-by: Oleg Nesterov
Acked-by: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
release_posix_timer() can't be called with ->it_process != NULL. Once
sys_timer_create() sets ->it_process it must not call
release_posix_timer(), otherwise we can race with another thread doing
sys_timer_delete(), this timer is visible to idr_find() and unlocked.The same is true for two other callers (actually, for any possible
caller), sys_timer_delete() and itimer_delete(). They must clear
->it_process before unlock_timer() + release_posix_timer().Signed-off-by: Oleg Nesterov
Acked-by: Roland McGrath
Cc: john stultz
Cc: Thomas Gleixner
Cc: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
sys_timer_delete() and itimer_delete() check "timer->it_process != NULL",
this looks completely bogus. ->it_process == NULL means that this timer
is already under destruction or it is not fully initialized, this must not
happen.sys_timer_delete: the timer is locked, and lock_timer() can't succeed
if ->it_process == NULL.itimer_delete: it is called by exit_itimers() when there are no other
threads which can play with signal_struct->posix_timers.Signed-off-by: Oleg Nesterov
Acked-by: Roland McGrath
Cc: john stultz
Cc: Thomas Gleixner
Cc: Roland McGrath
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
In cpuset_update_task_memory_state() local variable struct task_struct
*tsk = current;And local variable tsk is used 14 times and statement task_cs(tsk) is used
twice in this function. So using task_cs(tsk) instead of task_cs(current)
is better for readability.And "(struct cgroup_scanner *)&scan" is not good for readability also.
(and "container_of" is used in cpuset_do_move_task(), not
"(cpuset_hotplug_scanner *)scan")Signed-off-by: Lai Jiangshan
Acked-by: Paul Menage
Cc: Paul Jackson
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
cgroup(cgroup_scan_tasks) will initialize heap->gt for us. This patch
removes started_after() and its helper-function.Signed-off-by: Lai Jiangshan
Acked-by: Paul Menage
Cc: Paul Jackson
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
I create lots of empty cpusets(empty cpumasks) and turn off the
"sched_load_balance" in top cpuset.I found that all these empty cpumasks are passed to
partition_sched_domains() in rebuild_sched_domains(), it's very
time-consuming for partition_sched_domains() and it's not need.It also reduce memory consumed and some works in rebuild_sched_domains()
too.Signed-off-by: Lai Jiangshan
Acked-by: Paul Menage
Cc: Paul Jackson
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
When changing 'sched_relax_domain_level', don't rebuild sched domains if
'cpus' is empty or 'sched_load_balance' is not set.Also make the comments of rebuild_sched_domains() more readable.
Signed-off-by: Li Zefan
Cc: Hidetoshi Seto
Cc: Paul Jackson
Cc: Paul Menage
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
