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Re: [PATCH -tip v3&10 02/18] kprobes: Introduce generic insn_slot framework
- From: Masami Hiramatsu <mhiramat at redhat dot com>
- To: Mathieu Desnoyers <compudj at krystal dot dyndns dot org>
- Cc: Ingo Molnar <mingo at elte dot hu>, Frederic Weisbecker <fweisbec at gmail dot com>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, lkml <linux-kernel at vger dot kernel dot org>, systemtap <systemtap at sources dot redhat dot com>, DLE <dle-develop at lists dot sourceforge dot net>, Jim Keniston <jkenisto at us dot ibm dot com>, Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>, Christoph Hellwig <hch at infradead dot org>, Steven Rostedt <rostedt at goodmis dot org>, "H. Peter Anvin" <hpa at zytor dot com>, Anders Kaseorg <andersk at ksplice dot com>, Tim Abbott <tabbott at ksplice dot com>, Andi Kleen <andi at firstfloor dot org>, Jason Baron <jbaron at redhat dot com>
- Date: Mon, 01 Mar 2010 21:55:31 -0500
- Subject: Re: [PATCH -tip v3&10 02/18] kprobes: Introduce generic insn_slot framework
- References: <20100225133342.6725.26971.stgit@localhost6.localdomain6> <20100225133358.6725.82430.stgit@localhost6.localdomain6> <20100225152130.GB12635@Krystal>
Mathieu Desnoyers wrote:
> * Masami Hiramatsu (mhiramat@redhat.com) wrote:
>> Make insn_slot framework support various size slots.
>> Current insn_slot just supports one-size instruction buffer slot. However,
>> kprobes jump optimization needs larger size buffers.
>
> OK, so you end up having one insn slot cache for kprobes and one insn
> slot (eventually) for the static jump patching (which needs larger
> instruction slots than kprobes). That seems like a good way to ensure
> you do not use more memory than necessary.
>
> We could possibly go even further and automatically use the right insn
> slot cache given the size of the instruction entry that must be added (a
> bit like the memory allocator which have different pools for each
> allocation order).
Sure, that will be simpler interface.
> Possibly that using the terminology of "memory pools" rather than
> "cache" could be a better fit too. So what this really becomes is an
> instruction slot allocator and garbage collector.
Ah, right. It would be better to rename kprobe_insn_pool() :)
Thank you,
--
Masami Hiramatsu
e-mail: mhiramat@redhat.com