02 Oct, 2010

1 commit

  • The kfifo_dma family of functions use sg_mark_end() on the last element in
    their scatterlist. This forces use of a fresh scatterlist for each DMA
    operation, which makes recycling a single scatterlist impossible.

    Change the behavior of the kfifo_dma functions to match the usage of the
    dma_map_sg function. This means that users must respect the returned
    nents value. The sample code is updated to reflect the change.

    This bug is trivial to cause: call kfifo_dma_in_prepare() such that it
    prepares a scatterlist with a single entry comprising the whole fifo.
    This is the case when you map the entirety of a newly created empty fifo.
    This causes the setup_sgl() function to mark the first scatterlist entry
    as the end of the chain, no matter what comes after it.

    Afterwards, add and remove some data from the fifo such that another call
    to kfifo_dma_in_prepare() will create two scatterlist entries. It returns
    nents=2. However, due to the previous sg_mark_end() call, sg_is_last()
    will now return true for the first scatterlist element. This causes the
    sample code to print a single scatterlist element when it should print
    two.

    By removing the call to sg_mark_end(), we make the API as similar as
    possible to the DMA mapping API. All users are required to respect the
    returned nents.

    Signed-off-by: Ira W. Snyder
    Cc: Stefani Seibold
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Ira W. Snyder
     

21 Aug, 2010

5 commits

  • Provide a check in all the kfifo examples to validate the correct
    execution of each testcase.

    Signed-off-by: Andrea Righi
    Acked-by: Stefani Seibold
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Andrea Righi
     
  • We use a dynamically allocated kfifo in the dma example, so we need to
    free it when unloading the module.

    Signed-off-by: Andrea Righi
    Acked-by: Stefani Seibold
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Andrea Righi
     
  • The scatterlist is used uninitialized in kfifo_dma_in_prepare(). This
    triggers the following bug if CONFIG_DEBUG_SG=y:

    ------------[ cut here ]------------
    kernel BUG at include/linux/scatterlist.h:65!
    invalid opcode: 0000 [#1] PREEMPT SMP
    ...
    Call Trace:
    [] setup_sgl+0x6b/0xe0
    [] ? example_init+0x0/0x265 [dma_example]
    [] __kfifo_dma_in_prepare+0x21/0x30
    [] example_init+0x124/0x265 [dma_example]
    [] ? trace_module_notify+0x25/0x370
    [] ? free_pages_prepare+0x11e/0x1e0
    [] ? get_parent_ip+0x11/0x50
    [] ? trace_module_notify+0x25/0x370
    [] ? trace_hardirqs_on+0xd/0x10
    [] ? mutex_unlock+0xe/0x10
    [] ? trace_module_notify+0x41/0x370
    [] ? __blocking_notifier_call_chain+0x45/0x80
    [] ? vfree+0x2a/0x30
    [] ? up_read+0x23/0x40
    [] ? __blocking_notifier_call_chain+0x65/0x80
    [] do_one_initcall+0x43/0x180
    [] sys_init_module+0xba/0x200
    [] system_call_fastpath+0x16/0x1b
    RIP [] setup_sgl_buf+0x1a1/0x1b0
    RSP
    ---[ end trace a72b979fd3c1d3a5 ]---

    Add the proper initialization to avoid the bug.

    Signed-off-by: Andrea Righi
    Acked-by: Stefani Seibold
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Andrea Righi
     
  • Provide a static array of expected items that kfifo should contain at the
    end of the test to validate it.

    Signed-off-by: Andrea Righi
    Cc: Stefani Seibold
    Cc: Greg KH
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Andrea Righi
     
  • Add a testcase for kfifo_skip() to the byte stream fifo example.

    Signed-off-by: Andrea Righi
    Cc: Greg KH
    Acked-by: Stefani Seibold
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Andrea Righi
     

11 Aug, 2010

1 commit

  • Add four examples to the kernel sample directory.

    It shows how to handle:
    - a byte stream fifo
    - a integer type fifo
    - a dynamic record sized fifo
    - the fifo DMA functions

    [akpm@linux-foundation.org: coding-style fixes]
    Signed-off-by: Stefani Seibold
    Cc: Greg KH
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Stefani Seibold
     

05 Aug, 2010

1 commit

  • This KProbes example is a little useless if it doesn't print anything.
    For MIPS print similar messages to those produced on x86 and PPC.

    Signed-off-by: David Daney
    To: linux-mips@linux-mips.org
    To: ananth@in.ibm.com
    To: anil.s.keshavamurthy@intel.com
    To: davem@davemloft.net
    To: masami.hiramatsu.pt@hitachi.com
    Cc: linux-kernel@vger.kernel.org
    Cc: hschauhan@nulltrace.org
    Patchwork: https://patchwork.linux-mips.org/patch/1528/
    Signed-off-by: Ralf Baechle

    David Daney
     

14 May, 2010

1 commit

  • This patch adds data to be passed to tracepoint callbacks.

    The created functions from DECLARE_TRACE() now need a mandatory data
    parameter. For example:

    DECLARE_TRACE(mytracepoint, int value, value)

    Will create the register function:

    int register_trace_mytracepoint((void(*)(void *data, int value))probe,
    void *data);

    As the first argument, all callbacks (probes) must take a (void *data)
    parameter. So a callback for the above tracepoint will look like:

    void myprobe(void *data, int value)
    {
    }

    The callback may choose to ignore the data parameter.

    This change allows callbacks to register a private data pointer along
    with the function probe.

    void mycallback(void *data, int value);

    register_trace_mytracepoint(mycallback, mydata);

    Then the mycallback() will receive the "mydata" as the first parameter
    before the args.

    A more detailed example:

    DECLARE_TRACE(mytracepoint, TP_PROTO(int status), TP_ARGS(status));

    /* In the C file */

    DEFINE_TRACE(mytracepoint, TP_PROTO(int status), TP_ARGS(status));

    [...]

    trace_mytracepoint(status);

    /* In a file registering this tracepoint */

    int my_callback(void *data, int status)
    {
    struct my_struct my_data = data;
    [...]
    }

    [...]
    my_data = kmalloc(sizeof(*my_data), GFP_KERNEL);
    init_my_data(my_data);
    register_trace_mytracepoint(my_callback, my_data);

    The same callback can also be registered to the same tracepoint as long
    as the data registered is different. Note, the data must also be used
    to unregister the callback:

    unregister_trace_mytracepoint(my_callback, my_data);

    Because of the data parameter, tracepoints declared this way can not have
    no args. That is:

    DECLARE_TRACE(mytracepoint, TP_PROTO(void), TP_ARGS());

    will cause an error.

    If no arguments are needed, a new macro can be used instead:

    DECLARE_TRACE_NOARGS(mytracepoint);

    Since there are no arguments, the proto and args fields are left out.

    This is part of a series to make the tracepoint footprint smaller:

    text data bss dec hex filename
    4913961 1088356 861512 6863829 68bbd5 vmlinux.orig
    4914025 1088868 861512 6864405 68be15 vmlinux.class
    4918492 1084612 861512 6864616 68bee8 vmlinux.tracepoint

    Again, this patch also increases the size of the kernel, but
    lays the ground work for decreasing it.

    v5: Fixed net/core/drop_monitor.c to handle these updates.

    v4: Moved the DECLARE_TRACE() DECLARE_TRACE_NOARGS out of the
    #ifdef CONFIG_TRACE_POINTS, since the two are the same in both
    cases. The __DECLARE_TRACE() is what changes.
    Thanks to Frederic Weisbecker for pointing this out.

    v3: Made all register_* functions require data to be passed and
    all callbacks to take a void * parameter as its first argument.
    This makes the calling functions comply with C standards.

    Also added more comments to the modifications of DECLARE_TRACE().

    v2: Made the DECLARE_TRACE() have the ability to pass arguments
    and added a new DECLARE_TRACE_NOARGS() for tracepoints that
    do not need any arguments.

    Acked-by: Mathieu Desnoyers
    Acked-by: Masami Hiramatsu
    Acked-by: Frederic Weisbecker
    Cc: Neil Horman
    Cc: David S. Miller
    Signed-off-by: Steven Rostedt

    Steven Rostedt
     

30 Mar, 2010

1 commit

  • …it slab.h inclusion from percpu.h

    percpu.h is included by sched.h and module.h and thus ends up being
    included when building most .c files. percpu.h includes slab.h which
    in turn includes gfp.h making everything defined by the two files
    universally available and complicating inclusion dependencies.

    percpu.h -> slab.h dependency is about to be removed. Prepare for
    this change by updating users of gfp and slab facilities include those
    headers directly instead of assuming availability. As this conversion
    needs to touch large number of source files, the following script is
    used as the basis of conversion.

    http://userweb.kernel.org/~tj/misc/slabh-sweep.py

    The script does the followings.

    * Scan files for gfp and slab usages and update includes such that
    only the necessary includes are there. ie. if only gfp is used,
    gfp.h, if slab is used, slab.h.

    * When the script inserts a new include, it looks at the include
    blocks and try to put the new include such that its order conforms
    to its surrounding. It's put in the include block which contains
    core kernel includes, in the same order that the rest are ordered -
    alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
    doesn't seem to be any matching order.

    * If the script can't find a place to put a new include (mostly
    because the file doesn't have fitting include block), it prints out
    an error message indicating which .h file needs to be added to the
    file.

    The conversion was done in the following steps.

    1. The initial automatic conversion of all .c files updated slightly
    over 4000 files, deleting around 700 includes and adding ~480 gfp.h
    and ~3000 slab.h inclusions. The script emitted errors for ~400
    files.

    2. Each error was manually checked. Some didn't need the inclusion,
    some needed manual addition while adding it to implementation .h or
    embedding .c file was more appropriate for others. This step added
    inclusions to around 150 files.

    3. The script was run again and the output was compared to the edits
    from #2 to make sure no file was left behind.

    4. Several build tests were done and a couple of problems were fixed.
    e.g. lib/decompress_*.c used malloc/free() wrappers around slab
    APIs requiring slab.h to be added manually.

    5. The script was run on all .h files but without automatically
    editing them as sprinkling gfp.h and slab.h inclusions around .h
    files could easily lead to inclusion dependency hell. Most gfp.h
    inclusion directives were ignored as stuff from gfp.h was usually
    wildly available and often used in preprocessor macros. Each
    slab.h inclusion directive was examined and added manually as
    necessary.

    6. percpu.h was updated not to include slab.h.

    7. Build test were done on the following configurations and failures
    were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
    distributed build env didn't work with gcov compiles) and a few
    more options had to be turned off depending on archs to make things
    build (like ipr on powerpc/64 which failed due to missing writeq).

    * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
    * powerpc and powerpc64 SMP allmodconfig
    * sparc and sparc64 SMP allmodconfig
    * ia64 SMP allmodconfig
    * s390 SMP allmodconfig
    * alpha SMP allmodconfig
    * um on x86_64 SMP allmodconfig

    8. percpu.h modifications were reverted so that it could be applied as
    a separate patch and serve as bisection point.

    Given the fact that I had only a couple of failures from tests on step
    6, I'm fairly confident about the coverage of this conversion patch.
    If there is a breakage, it's likely to be something in one of the arch
    headers which should be easily discoverable easily on most builds of
    the specific arch.

    Signed-off-by: Tejun Heo <tj@kernel.org>
    Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

    Tejun Heo
     

10 Mar, 2010

1 commit


08 Mar, 2010

3 commits

  • Constify struct sysfs_ops.

    This is part of the ops structure constification
    effort started by Arjan van de Ven et al.

    Benefits of this constification:

    * prevents modification of data that is shared
    (referenced) by many other structure instances
    at runtime

    * detects/prevents accidental (but not intentional)
    modification attempts on archs that enforce
    read-only kernel data at runtime

    * potentially better optimized code as the compiler
    can assume that the const data cannot be changed

    * the compiler/linker move const data into .rodata
    and therefore exclude them from false sharing

    Signed-off-by: Emese Revfy
    Acked-by: David Teigland
    Acked-by: Matt Domsch
    Acked-by: Maciej Sosnowski
    Acked-by: Hans J. Koch
    Acked-by: Pekka Enberg
    Acked-by: Jens Axboe
    Acked-by: Stephen Hemminger
    Signed-off-by: Greg Kroah-Hartman

    Emese Revfy
     
  • No change in functionality.

    Signed-off-by: Radu Voicilas
    Signed-off-by: Greg Kroah-Hartman

    Radu Voicilas
     
  • No change in functionality.

    Signed-off-by: Radu Voicilas
    Signed-off-by: Greg Kroah-Hartman

    Radu Voicilas
     

27 Feb, 2010

1 commit

  • Add __percpu sparse annotations to hw_breakpoint.

    These annotations are to make sparse consider percpu variables to be
    in a different address space and warn if accessed without going
    through percpu accessors. This patch doesn't affect normal builds.

    In kernel/hw_breakpoint.c, per_cpu(nr_task_bp_pinned, cpu)'s will
    trigger spurious noderef related warnings from sparse. Changing it to
    &per_cpu(nr_task_bp_pinned[0], cpu) will work around the problem but
    deemed to ugly by the maintainer. Leave it alone until better
    solution can be found.

    Signed-off-by: Tejun Heo
    Cc: Stephen Rothwell
    Cc: K.Prasad
    LKML-Reference:
    Signed-off-by: Frederic Weisbecker

    Tejun Heo
     

12 Dec, 2009

1 commit

  • …/git/tip/linux-2.6-tip

    * 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (57 commits)
    x86, perf events: Check if we have APIC enabled
    perf_event: Fix variable initialization in other codepaths
    perf kmem: Fix unused argument build warning
    perf symbols: perf_header__read_build_ids() offset'n'size should be u64
    perf symbols: dsos__read_build_ids() should read both user and kernel buildids
    perf tools: Align long options which have no short forms
    perf kmem: Show usage if no option is specified
    sched: Mark sched_clock() as notrace
    perf sched: Add max delay time snapshot
    perf tools: Correct size given to memset
    perf_event: Fix perf_swevent_hrtimer() variable initialization
    perf sched: Fix for getting task's execution time
    tracing/kprobes: Fix field creation's bad error handling
    perf_event: Cleanup for cpu_clock_perf_event_update()
    perf_event: Allocate children's perf_event_ctxp at the right time
    perf_event: Clean up __perf_event_init_context()
    hw-breakpoints: Modify breakpoints without unregistering them
    perf probe: Update perf-probe document
    perf probe: Support --del option
    trace-kprobe: Support delete probe syntax
    ...

    Linus Torvalds
     

08 Dec, 2009

1 commit


06 Dec, 2009

1 commit

  • struct perf_event::event callback was called when a breakpoint
    triggers. But this is a rather opaque callback, pretty
    tied-only to the breakpoint API and not really integrated into perf
    as it triggers even when we don't overflow.

    We prefer to use overflow_handler() as it fits into the perf events
    rules, being called only when we overflow.

    Reported-by: Peter Zijlstra
    Signed-off-by: Frederic Weisbecker
    Cc: Paul Mackerras
    Cc: Arnaldo Carvalho de Melo
    Cc: "K. Prasad"

    Frederic Weisbecker
     

27 Nov, 2009

1 commit

  • Kernel breakpoints are created using functions in which we pass
    breakpoint parameters as individual variables: address, length
    and type.

    Although it fits well for x86, this just does not scale across
    architectures that may support this api later as these may have
    more or different needs. Pass in a perf_event_attr structure
    instead because it is meant to evolve as much as possible into
    a generic hardware breakpoint parameter structure.

    Reported-by: K.Prasad
    Signed-off-by: Frederic Weisbecker
    LKML-Reference:
    Signed-off-by: Ingo Molnar

    Frederic Weisbecker
     

26 Nov, 2009

1 commit

  • This simplifies the error handling when we create a breakpoint.
    We don't need to check the NULL return value corner case anymore
    since we have improved perf_event_create_kernel_counter() to
    always return an error code in the failure case.

    Signed-off-by: Frederic Weisbecker
    Cc: Peter Zijlstra
    Cc: Arnaldo Carvalho de Melo
    Cc: Paul Mackerras
    Cc: Steven Rostedt
    Cc: Prasad
    LKML-Reference:
    Signed-off-by: Ingo Molnar

    Frederic Weisbecker
     

24 Nov, 2009

1 commit


10 Nov, 2009

1 commit


09 Nov, 2009

1 commit


18 Oct, 2009

1 commit


02 Oct, 2009

1 commit


19 Sep, 2009

1 commit

  • Now that the last users of markers have migrated to the event
    tracer we can kill off the (now orphan) support code.

    Signed-off-by: Christoph Hellwig
    Acked-by: Mathieu Desnoyers
    Cc: Steven Rostedt
    Cc: Frederic Weisbecker
    LKML-Reference:
    Signed-off-by: Ingo Molnar

    Christoph Hellwig
     

16 Sep, 2009

1 commit


15 Sep, 2009

1 commit


07 Sep, 2009

1 commit


17 Aug, 2009

1 commit


13 Jul, 2009

1 commit

  • If TRACE_INCLDUE_FILE is defined,
    will be included and compiled, otherwise it will be

    So TRACE_SYSTEM should be defined outside of #if proctection,
    just like TRACE_INCLUDE_FILE.

    Imaging this scenario:

    #include
    -> TRACE_SYSTEM == foo
    ...
    #include
    -> TRACE_SYSTEM == bar
    ...
    #define CREATE_TRACE_POINTS
    #include
    -> TRACE_SYSTEM == bar !!!

    and then bar.h will be included and compiled.

    Signed-off-by: Li Zefan
    Cc: Steven Rostedt
    Cc: Frederic Weisbecker
    LKML-Reference:
    Signed-off-by: Ingo Molnar

    Li Zefan
     

21 Jun, 2009

1 commit

  • …nel/git/tip/linux-2.6-tip

    * 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (24 commits)
    tracing/urgent: warn in case of ftrace_start_up inbalance
    tracing/urgent: fix unbalanced ftrace_start_up
    function-graph: add stack frame test
    function-graph: disable when both x86_32 and optimize for size are configured
    ring-buffer: have benchmark test print to trace buffer
    ring-buffer: do not grab locks in nmi
    ring-buffer: add locks around rb_per_cpu_empty
    ring-buffer: check for less than two in size allocation
    ring-buffer: remove useless compile check for buffer_page size
    ring-buffer: remove useless warn on check
    ring-buffer: use BUF_PAGE_HDR_SIZE in calculating index
    tracing: update sample event documentation
    tracing/filters: fix race between filter setting and module unload
    tracing/filters: free filter_string in destroy_preds()
    ring-buffer: use commit counters for commit pointer accounting
    ring-buffer: remove unused variable
    ring-buffer: have benchmark test handle discarded events
    ring-buffer: prevent adding write in discarded area
    tracing/filters: strloc should be unsigned short
    tracing/filters: operand can be negative
    ...

    Fix up kmemcheck-induced conflict in kernel/trace/ring_buffer.c manually

    Linus Torvalds
     

17 Jun, 2009

2 commits


16 Jun, 2009

2 commits


03 Jun, 2009

1 commit


07 May, 2009

1 commit

  • When creating trace events for ftrace, the header file with the TRACE_EVENT
    macros must also have a macro called TRACE_SYSTEM. This macro describes
    the name of the system the TRACE_EVENTS are defined for. It also doubles
    as a way for the define_trace.h file to include the file that included
    it.

    For example:

    in irq.h

    #define TRACE_SYSTEM irq

    [...]

    #include

    The define_trace will use TRACE_SYSTEM to include irq.h. But if the name
    of the trace system does not match the name of the trace header file,
    one can override it with:

    Which will change define_trace.h to inclued foo_trace.h instead of foo.h

    The sample comments this, but people that use the sample code will more
    likely use the code and not read the comments. This patch changes the
    sample code to use the TRACE_INCLUDE_FILE to better show developers how to
    use it.

    [ Impact: make sample less confusing to developers ]

    Reported-by: Christoph Hellwig
    Signed-off-by: Steven Rostedt

    Steven Rostedt
     

06 May, 2009

2 commits