Eric Lee / smarc-fsl-linux-kernel

24 Nov, 2011

1 commit

  • 34b087e48   freezer: kill unused set_freezable_with_signal() ... Browse Code »

    There's no in-kernel user of set_freezable_with_signal() left. Mixing
    TIF_SIGPENDING with kernel threads can lead to nasty corner cases as
    kernel threads never travel signal delivery path on their own.

    e.g. the current implementation is buggy in the cancelation path of
    __thaw_task(). It calls recalc_sigpending_and_wake() in an attempt to
    clear TIF_SIGPENDING but the function never clears it regardless of
    sigpending state. This means that signallable freezable kthreads may
    continue executing with !freezing() && stuck TIF_SIGPENDING, which can
    be troublesome.

    This patch removes set_freezable_with_signal() along with
    PF_FREEZER_NOSIG and recalc_sigpending*() calls in freezer. User
    tasks get TIF_SIGPENDING, kernel tasks get woken up and the spurious
    sigpending is dealt with in the usual signal delivery path.

    Signed-off-by: Tejun Heo
    Acked-by: Oleg Nesterov

    Tejun Heo
     

22 Nov, 2011

1 commit

  • 8a32c441c   freezer: implement and use kthread_freezable_should_stop() ... Browse Code »

    Writeback and thinkpad_acpi have been using thaw_process() to prevent
    deadlock between the freezer and kthread_stop(); unfortunately, this
    is inherently racy - nothing prevents freezing from happening between
    thaw_process() and kthread_stop().

    This patch implements kthread_freezable_should_stop() which enters
    refrigerator if necessary but is guaranteed to return if
    kthread_stop() is invoked. Both thaw_process() users are converted to
    use the new function.

    Note that this deadlock condition exists for many of freezable
    kthreads. They need to be converted to use the new should_stop or
    freezable workqueue.

    Tested with synthetic test case.

    Signed-off-by: Tejun Heo
    Acked-by: Henrique de Moraes Holschuh
    Cc: Jens Axboe
    Cc: Oleg Nesterov

    Tejun Heo
     

31 Oct, 2011

1 commit

  • 9984de1a5   kernel: Map most files to use export.h instead of module.h ... Browse Code »

    The changed files were only including linux/module.h for the
    EXPORT_SYMBOL infrastructure, and nothing else. Revector them
    onto the isolated export header for faster compile times.

    Nothing to see here but a whole lot of instances of:

    -#include
    +#include

    This commit is only changing the kernel dir; next targets
    will probably be mm, fs, the arch dirs, etc.

    Signed-off-by: Paul Gortmaker

    Paul Gortmaker
     

28 May, 2011

1 commit

31 Mar, 2011

1 commit

23 Mar, 2011

1 commit

  • 207205a2b   kthread: NUMA aware kthread_create_on_node() ... Browse Code »

    All kthreads being created from a single helper task, they all use memory
    from a single node for their kernel stack and task struct.

    This patch suite creates kthread_create_on_node(), adding a 'cpu' parameter
    to parameters already used by kthread_create().

    This parameter serves in allocating memory for the new kthread on its
    memory node if possible.

    Signed-off-by: Eric Dumazet
    Acked-by: David S. Miller
    Reviewed-by: Andi Kleen
    Acked-by: Rusty Russell
    Cc: Tejun Heo
    Cc: Tony Luck
    Cc: Fenghua Yu
    Cc: David Howells
    Cc:
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Eric Dumazet
     

07 Jan, 2011

1 commit

05 Jan, 2011

1 commit

22 Dec, 2010

1 commit

  • 4f32e9b1f   kthread_work: make lockdep happy ... Browse Code »

    spinlock in kthread_worker and wait_queue_head in kthread_work both
    should be lockdep sensible, so change the interface to make it
    suiltable for CONFIG_LOCKDEP.

    tj: comment update

    Reported-by: Nicolas
    Signed-off-by: Yong Zhang
    Signed-off-by: Andy Walls
    Tested-by: Andy Walls
    Cc: Tejun Heo
    Cc: Andrew Morton
    Signed-off-by: Tejun Heo

    Yong Zhang
     

23 Oct, 2010

1 commit

29 Jun, 2010

2 commits

  • 82805ab77   kthread: implement kthread_data() ... Browse Code »

    Implement kthread_data() which takes @task pointing to a kthread and
    returns @data specified when creating the kthread. The caller is
    responsible for ensuring the validity of @task when calling this
    function.

    Signed-off-by: Tejun Heo

    Tejun Heo
     
  • b56c0d893   kthread: implement kthread_worker ... Browse Code »

    Implement simple work processor for kthread. This is to ease using
    kthread. Single thread workqueue used to be used for things like this
    but workqueue won't guarantee fixed kthread association anymore to
    enable worker sharing.

    This can be used in cases where specific kthread association is
    necessary, for example, when it should have RT priority or be assigned
    to certain cgroup.

    Signed-off-by: Tejun Heo
    Cc: Andrew Morton

    Tejun Heo
     

25 Mar, 2010

1 commit

  • 5ab116c93   cpuset: fix the problem that cpuset_mem_spread_node() returns an offline node ... Browse Code »

    cpuset_mem_spread_node() returns an offline node, and causes an oops.

    This patch fixes it by initializing task->mems_allowed to
    node_states[N_HIGH_MEMORY], and updating task->mems_allowed when doing
    memory hotplug.

    Signed-off-by: Miao Xie
    Acked-by: David Rientjes
    Reported-by: Nick Piggin
    Tested-by: Nick Piggin
    Cc: Paul Menage
    Cc: Li Zefan
    Cc: Ingo Molnar
    Cc:
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Miao Xie
     

09 Feb, 2010

1 commit

17 Dec, 2009

1 commit

03 Nov, 2009

1 commit

  • b84ff7d6f   sched: Fix kthread_bind() by moving the body of kthread_bind() to sched.c ... Browse Code »

    Eric Paris reported that commit
    f685ceacab07d3f6c236f04803e2f2f0dbcc5afb causes boot time
    PREEMPT_DEBUG complaints.

    [ 4.590699] BUG: using smp_processor_id() in preemptible [00000000] code: rmmod/1314
    [ 4.593043] caller is task_hot+0x86/0xd0

    Since kthread_bind() messes with scheduler internals, move the
    body to sched.c, and lock the runqueue.

    Reported-by: Eric Paris
    Signed-off-by: Mike Galbraith
    Tested-by: Eric Paris
    Cc: Peter Zijlstra
    LKML-Reference:
    [ v2: fix !SMP build and clean up ]
    Signed-off-by: Ingo Molnar

    Mike Galbraith
     

09 Sep, 2009

1 commit

28 Jul, 2009

1 commit

  • 9ae260270   update the comment in kthread_stop() ... Browse Code »

    Commit 63706172f332fd3f6e7458ebfb35fa6de9c21dc5 ("kthreads: rework
    kthread_stop()") removed the limitation that the thread function mysr
    not call do_exit() itself, but forgot to update the comment.

    Since that commit it is OK to use kthread_stop() even if kthread can
    exit itself.

    Signed-off-by: Oleg Nesterov
    Signed-off-by: Rusty Russell
    Signed-off-by: Linus Torvalds

    Oleg Nesterov
     

19 Jun, 2009

2 commits

  • 63706172f   kthreads: rework kthread_stop() ... Browse Code »
    43

    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
    Cc: Christoph Hellwig
    Cc: "Eric W. Biederman"
    Cc: Ingo Molnar
    Cc: Pavel Emelyanov
    Cc: Rusty Russell
    Cc: Vitaliy Gusev
    Signed-off-by: Linus Torvalds

    Oleg Nesterov
     
  • cdd140bdd   kthreads: simplify the startup synchronization ... Browse Code »

    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
    Cc: Christoph Hellwig
    Cc: "Eric W. Biederman"
    Cc: Ingo Molnar
    Cc: Pavel Emelyanov
    Cc: Rusty Russell
    Cc: Vitaliy Gusev
    Signed-off-by: Linus Torvalds

    Oleg Nesterov
     

17 Jun, 2009

1 commit

  • 58568d2a8   cpuset,mm: update tasks' mems_allowed in time ... Browse Code »

    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
    Cc: Ingo Molnar
    Cc: Peter Zijlstra
    Cc: Christoph Lameter
    Cc: Paul Menage
    Cc: Nick Piggin
    Cc: Yasunori Goto
    Cc: Pekka Enberg
    Cc: David Rientjes
    Signed-off-by: Lee Schermerhorn
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Miao Xie
     

15 Apr, 2009

2 commits

  • ad8d75fff   tracing/events: move trace point headers into include/trace/events ... Browse Code »

    Impact: clean up

    Create a sub directory in include/trace called events to keep the
    trace point headers in their own separate directory. Only headers that
    declare trace points should be defined in this directory.

    Cc: Peter Zijlstra
    Cc: Thomas Gleixner
    Cc: Neil Horman
    Cc: Zhao Lei
    Cc: Eduard - Gabriel Munteanu
    Cc: Pekka Enberg
    Signed-off-by: Steven Rostedt

    Steven Rostedt
     
  • a8d154b00   tracing: create automated trace defines ... Browse Code »

    This patch lowers the number of places a developer must modify to add
    new tracepoints. The current method to add a new tracepoint
    into an existing system is to write the trace point macro in the
    trace header with one of the macros TRACE_EVENT, TRACE_FORMAT or
    DECLARE_TRACE, then they must add the same named item into the C file
    with the macro DEFINE_TRACE(name) and then add the trace point.

    This change cuts out the needing to add the DEFINE_TRACE(name).
    Every file that uses the tracepoint must still include the trace/.h
    file, but the one C file must also add a define before the including
    of that file.

    #define CREATE_TRACE_POINTS
    #include

    This will cause the trace/mytrace.h file to also produce the C code
    necessary to implement the trace point.

    Note, if more than one trace/.h is used to create the C code
    it is best to list them all together.

    #define CREATE_TRACE_POINTS
    #include
    #include
    #include

    Thanks to Mathieu Desnoyers and Christoph Hellwig for coming up with
    the cleaner solution of the define above the includes over my first
    design to have the C code include a "special" header.

    This patch converts sched, irq and lockdep and skb to use this new
    method.

    Cc: Peter Zijlstra
    Cc: Thomas Gleixner
    Cc: Neil Horman
    Cc: Zhao Lei
    Cc: Eduard - Gabriel Munteanu
    Cc: Pekka Enberg
    Signed-off-by: Steven Rostedt

    Steven Rostedt
     

09 Apr, 2009

2 commits

30 Mar, 2009

1 commit

  • 1a2142afa   cpumask: remove dangerous CPU_MASK_ALL_PTR, &CPU_MASK_ALL ... Browse Code »

    Impact: cleanup

    (Thanks to Al Viro for reminding me of this, via Ingo)

    CPU_MASK_ALL is the (deprecated) "all bits set" cpumask, defined as so:

    #define CPU_MASK_ALL (cpumask_t) { { ... } }

    Taking the address of such a temporary is questionable at best,
    unfortunately 321a8e9d (cpumask: add CPU_MASK_ALL_PTR macro) added
    CPU_MASK_ALL_PTR:

    #define CPU_MASK_ALL_PTR (&CPU_MASK_ALL)

    Which formalizes this practice. One day gcc could bite us over this
    usage (though we seem to have gotten away with it so far).

    So replace everywhere which used &CPU_MASK_ALL or CPU_MASK_ALL_PTR
    with the modern "cpu_all_mask" (a real const struct cpumask *).

    Signed-off-by: Rusty Russell
    Acked-by: Ingo Molnar
    Reported-by: Al Viro
    Cc: Mike Travis

    Rusty Russell
     

16 Nov, 2008

1 commit

  • 7e066fb87   tracepoints: add DECLARE_TRACE() and DEFINE_TRACE() ... Browse Code »

    Impact: API *CHANGE*. Must update all tracepoint users.

    Add DEFINE_TRACE() to tracepoints to let them declare the tracepoint
    structure in a single spot for all the kernel. It helps reducing memory
    consumption, especially when declaring a lot of tracepoints, e.g. for
    kmalloc tracing.

    *API CHANGE WARNING*: now, DECLARE_TRACE() must be used in headers for
    tracepoint declarations rather than DEFINE_TRACE(). This is the sane way
    to do it. The name previously used was misleading.

    Updates scheduler instrumentation to follow this API change.

    Signed-off-by: Mathieu Desnoyers
    Signed-off-by: Ingo Molnar

    Mathieu Desnoyers
     

21 Oct, 2008

1 commit

  • 92b29b86f   Merge branch 'tracing-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kerne… ... Browse Code »

    …l/git/tip/linux-2.6-tip

    * 'tracing-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (131 commits)
    tracing/fastboot: improve help text
    tracing/stacktrace: improve help text
    tracing/fastboot: fix initcalls disposition in bootgraph.pl
    tracing/fastboot: fix bootgraph.pl initcall name regexp
    tracing/fastboot: fix issues and improve output of bootgraph.pl
    tracepoints: synchronize unregister static inline
    tracepoints: tracepoint_synchronize_unregister()
    ftrace: make ftrace_test_p6nop disassembler-friendly
    markers: fix synchronize marker unregister static inline
    tracing/fastboot: add better resolution to initcall debug/tracing
    trace: add build-time check to avoid overrunning hex buffer
    ftrace: fix hex output mode of ftrace
    tracing/fastboot: fix initcalls disposition in bootgraph.pl
    tracing/fastboot: fix printk format typo in boot tracer
    ftrace: return an error when setting a nonexistent tracer
    ftrace: make some tracers reentrant
    ring-buffer: make reentrant
    ring-buffer: move page indexes into page headers
    tracing/fastboot: only trace non-module initcalls
    ftrace: move pc counter in irqtrace
    ...

    Manually fix conflicts:
    - init/main.c: initcall tracing
    - kernel/module.c: verbose level vs tracepoints
    - scripts/bootgraph.pl: fallout from cherry-picking commits.

    Linus Torvalds
     

20 Oct, 2008

1 commit

14 Oct, 2008

1 commit

  • 0a16b6075   tracing, sched: LTTng instrumentation - scheduler ... Browse Code »

    Instrument the scheduler activity (sched_switch, migration, wakeups,
    wait for a task, signal delivery) and process/thread
    creation/destruction (fork, exit, kthread stop). Actually, kthread
    creation is not instrumented in this patch because it is architecture
    dependent. It allows to connect tracers such as ftrace which detects
    scheduling latencies, good/bad scheduler decisions. Tools like LTTng can
    export this scheduler information along with instrumentation of the rest
    of the kernel activity to perform post-mortem analysis on the scheduler
    activity.

    About the performance impact of tracepoints (which is comparable to
    markers), even without immediate values optimizations, tests done by
    Hideo Aoki on ia64 show no regression. His test case was using hackbench
    on a kernel where scheduler instrumentation (about 5 events in code
    scheduler code) was added. See the "Tracepoints" patch header for
    performance result detail.

    Changelog :

    - Change instrumentation location and parameter to match ftrace
    instrumentation, previously done with kernel markers.

    [ mingo@elte.hu: conflict resolutions ]
    Signed-off-by: Mathieu Desnoyers
    Acked-by: 'Peter Zijlstra'
    Signed-off-by: Ingo Molnar

    Mathieu Desnoyers
     

27 Jul, 2008

1 commit

  • 85ba2d862   tracehook: wait_task_inactive ... Browse Code »

    This extends wait_task_inactive() with a new argument so it can be used in
    a "soft" mode where it will check for the task changing state unexpectedly
    and back off. There is no change to existing callers. This lays the
    groundwork to allow robust, noninvasive tracing that can try to sample a
    blocked thread but back off safely if it wakes up.

    Signed-off-by: Roland McGrath
    Cc: Oleg Nesterov
    Reviewed-by: Ingo Molnar
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Roland McGrath
     

19 Jul, 2008

1 commit

17 Jul, 2008

1 commit

  • ebb12db51   Freezer: Introduce PF_FREEZER_NOSIG ... Browse Code »

    The freezer currently attempts to distinguish kernel threads from
    user space tasks by checking if their mm pointer is unset and it
    does not send fake signals to kernel threads. However, there are
    kernel threads, mostly related to networking, that behave like
    user space tasks and may want to be sent a fake signal to be frozen.

    Introduce the new process flag PF_FREEZER_NOSIG that will be set
    by default for all kernel threads and make the freezer only send
    fake signals to the tasks having PF_FREEZER_NOSIG unset. Provide
    the set_freezable_with_signal() function to be called by the kernel
    threads that want to be sent a fake signal for freezing.

    This patch should not change the freezer's observable behavior.

    Signed-off-by: Rafael J. Wysocki
    Signed-off-by: Andi Kleen
    Acked-by: Pavel Machek
    Signed-off-by: Len Brown

    Rafael J. Wysocki
     

10 Jun, 2008

1 commit

  • 9985b0bab   sched: prevent bound kthreads from changing cpus_allowed ... Browse Code »

    Kthreads that have called kthread_bind() are bound to specific cpus, so
    other tasks should not be able to change their cpus_allowed from under
    them. Otherwise, it is possible to move kthreads, such as the migration
    or software watchdog threads, so they are not allowed access to the cpu
    they work on.

    Cc: Peter Zijlstra
    Cc: Paul Menage
    Cc: Paul Jackson
    Signed-off-by: David Rientjes
    Signed-off-by: Ingo Molnar

    David Rientjes
     

30 Apr, 2008

1 commit

  • 5cd204550   Deprecate find_task_by_pid() ... Browse Code »

    There are some places that are known to operate on tasks'
    global pids only:

    * the rest_init() call (called on boot)
    * the kgdb's getthread
    * the create_kthread() (since the kthread is run in init ns)

    So use the find_task_by_pid_ns(..., &init_pid_ns) there
    and schedule the find_task_by_pid for removal.

    [sukadev@us.ibm.com: Fix warning in kernel/pid.c]
    Signed-off-by: Pavel Emelyanov
    Cc: "Eric W. Biederman"
    Signed-off-by: Sukadev Bhattiprolu
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Pavel Emelyanov
     

29 Apr, 2008

1 commit

  • cbd9b67bd   kthread: call wake_up_process() without the lock being held ... Browse Code »

    From the POV of synchronization, there should be no need to call
    wake_up_process() with the 'kthread_create_lock' being held.

    Signed-off-by: Dmitry Adamushko
    Cc: Nick Piggin
    Cc: Ingo Molnar
    Cc: Rusty Russell
    Cc: "Paul E. McKenney"
    Cc: Peter Zijlstra
    Cc: Andy Whitcroft
    Cc: Oleg Nesterov
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Dmitry Adamushko
     

22 Apr, 2008

1 commit

  • 429f731de   Merge branch 'semaphore' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc ... Browse Code »

    * 'semaphore' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc:
    Deprecate the asm/semaphore.h files in feature-removal-schedule.
    Convert asm/semaphore.h users to linux/semaphore.h
    security: Remove unnecessary inclusions of asm/semaphore.h
    lib: Remove unnecessary inclusions of asm/semaphore.h
    kernel: Remove unnecessary inclusions of asm/semaphore.h
    include: Remove unnecessary inclusions of asm/semaphore.h
    fs: Remove unnecessary inclusions of asm/semaphore.h
    drivers: Remove unnecessary inclusions of asm/semaphore.h
    net: Remove unnecessary inclusions of asm/semaphore.h
    arch: Remove unnecessary inclusions of asm/semaphore.h

    Linus Torvalds
     

20 Apr, 2008

1 commit

19 Apr, 2008

1 commit

26 Jan, 2008

1 commit