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SubjectRe: [GIT PULL] uprobes: pre-filtering
Hello Ingo,

On Thu, Jan 24, 2013 at 11:17 PM, Ingo Molnar <mingo@kernel.org> wrote:
>
> * Oleg Nesterov <oleg@redhat.com> wrote:
>
>> Ingo, please pull from
>>
>> git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc uprobes/core
>>
>> Mostly pre-filtering. This needs more work and perhaps more functionality.
>> In particular, perhaps dup_mmap() should remove the unwanted breakpoints.
>> And we can add more ->filter() hooks to, say, speedup uprobe_register().
>> Plus we can do some optimizations to avoid register_for_each_vma() in
>> case when we know that all mm's were previously acked/nacked.
>>
>> Srikar, the only patch you did not ack explicitely is 1fecb96d
>> "Do not allocate current->utask unnecessary", but afaics you do not
>> object.
>>
>> And the patch from Josh which exports uprobe_register/unregister for modules.
>> Christoph (cc'ed) doesn't like this change, but I disagree. Whatever you
>> think about systemtap it is the widely used tool, and uprobes can have other
>> out-of-tree users. This is like kprobes, kprobe_register() is exported but
>> it doesn't have a modular in-kernel user too. I do not see why should we
>> limit the usage of uprobes.
>>
>>
>>
>> Josh Stone (1):
>> uprobes: Add exports for module use
>>
>> Oleg Nesterov (26):
>> uprobes: Move __set_bit(UPROBE_SKIP_SSTEP) into alloc_uprobe()
>> uprobes: Kill the "uprobe != NULL" check in uprobe_unregister()
>> uprobes: Kill the pointless inode/uc checks in register/unregister
>> uprobes: Kill uprobe_consumer->filter()
>> uprobes: Introduce filter_chain()
>> uprobes: _unregister() should always do register_for_each_vma(false)
>> uprobes: _register() should always do register_for_each_vma(true)
>> uprobes: Introduce uprobe->register_rwsem
>> uprobes: Change filter_chain() to iterate ->consumers list
>> uprobes: Kill UPROBE_RUN_HANDLER flag
>> uprobes: Kill uprobe->copy_mutex
>> uprobes: Kill uprobe_events, use RB_EMPTY_ROOT() instead
>> uprobes: Introduce uprobe_is_active()
>> uprobes: Kill uprobes_mutex[], separate alloc_uprobe() and __uprobe_register()
>> uprobes: Rationalize the usage of filter_chain()
>> uprobes: Reintroduce uprobe_consumer->filter()
>> uprobes: Teach handler_chain() to filter out the probed task
>> uprobes/x86: Change __skip_sstep() to actually skip the whole insn
>> uprobes: Change handle_swbp() to expose bp_vaddr to handler_chain()
>> uprobes: Move alloc_page() from xol_add_vma() to xol_alloc_area()
>> uprobes: Fold xol_alloc_area() into get_xol_area()
>> uprobes: Turn add_utask() into get_utask()
>> uprobes: Do not play with utask in xol_get_insn_slot()
>> uprobes: Fix utask->xol_vaddr leak in pre_ssout()
>> uprobes: Do not allocate current->utask unnecessary
>> uprobes: Kill the bogus IS_ERR_VALUE(xol_vaddr) check
>>
>> arch/x86/kernel/uprobes.c | 4 +-
>> include/linux/uprobes.h | 17 ++-
>> kernel/events/uprobes.c | 433 ++++++++++++++++++++++---------------------
>> kernel/ptrace.c | 6 +
>> kernel/trace/trace_uprobe.c | 5 +-
>> 5 files changed, 243 insertions(+), 222 deletions(-)
>
> The kernel side looks good to me - but how does 'perf uprobe'
> make use of it in practice, how can I test it?

I'm not sure whether you looking into testing specific changes in this
pull, but in general, syntax is:
perf probe -x /lib64/libc.so.6 malloc
perf record -e probe_libc:p_malloc -aR sleep 30

hope this is what you was looking for,
Anton.


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