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Message-ID: <20130124123010.GA4755@gmail.com>
Date: Thu, 24 Jan 2013 13:30:10 +0100
From: Ingo Molnar <mingo@...nel.org>
To: Anton Arapov <anton@...hat.com>
Cc: Oleg Nesterov <oleg@...hat.com>, Ingo Molnar <mingo@...e.hu>,
Christoph Hellwig <hch@...radead.org>,
Josh Stone <jistone@...hat.com>,
Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
linux-kernel@...r.kernel.org
Subject: Re: [GIT PULL] uprobes: pre-filtering
* Anton Arapov <anton@...hat.com> wrote:
> Hello Ingo,
>
> On Thu, Jan 24, 2013 at 11:17 PM, Ingo Molnar <mingo@...nel.org> wrote:
> >
> > * Oleg Nesterov <oleg@...hat.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, [...]
Yes, I was curious about specifically testing the filtering
callback changes in this pull request.
Thanks,
Ingo
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