Messages in this thread | | | From | Roland McGrath <> | Subject | Re: [RFC patch 00/20] Kernel tracing thread flag | Date | Sun, 10 May 2009 16:04:35 -0700 (PDT) |
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I suspect you will hit troubles with some arch's not having a bit to spare. (Even on x86, it probably hurts several bytes of cache wastage to have to use longer immediates in some 'test' instructions.)
Another direction to go for this is overloading TIF_SYSCALL_TRACE, so we do not need any arch changes. Before the end of the ptrace cleanup work that Oleg is in the middle of, it should become simple to divorce ptrace's own bookkeeping from TIF_SYSCALL_TRACE. At that point, we just need a little bit of cooperation (in generic non-arch code) to overload that bit for multiple simultaneous purposes.
Thanks, Roland
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