Messages in this thread | | | Date | Mon, 2 Mar 2015 13:43:29 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH 07/15] mm: Add ___GFP_NOTRACE |
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On Mon, 2 Mar 2015 10:12:32 -0800 Alexei Starovoitov <ast@plumgrid.com> wrote:
> I'm not sure what would be the meaning of hash map that has all > elements pre-allocated... > As I'm reading your cover letter, I agree, we need to find a way > to call kmalloc_notrace-like from tracepoints. > Not sure that patch 8 style of duplicating the functions is clean. > Can we keep kmalloc/kfree as-is and do something like > if (in_tracepoint()) check inside ftrace_raw_kmalloc* ?
I'm strongly against this. You should not be doing anything in a tracepoint that you can't do from NMI context. And calling kmalloc happens to be one of them.
Not to mention, kmalloc is a hot path, and tracing must not have any impact on it (no extra if statements).
-- Steve
> so that kmalloc will be traced but calls to kmalloc from inside > tracepoints will be automatically suppressed ?
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