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    SubjectRe: [BUG] percpu misaligned allocation
    From
    From: Frederic Weisbecker <fweisbec@gmail.com>
    Date: Fri, 19 Mar 2010 02:31:22 +0100

    > On Thu, Mar 18, 2010 at 05:54:13PM -0700, David Miller wrote:
    >> From: Tejun Heo <tj@kernel.org>
    >> Date: Thu, 18 Mar 2010 18:30:34 +0900
    >>
    >> >
    >> > if (!total_profile_count) {
    >> > - buf = (char *)alloc_percpu(perf_trace_t);
    >> > + buf = (char *)__alloc_percpu(sizeof(perf_trace_t),
    >> > + __alignof__(unsigned long));
    >> > if (!buf)
    >> > goto fail_buf;
    >>
    >> Why not make perf_trace_t have the proper alignment?
    >
    >
    > So, making perf_trace_t as align(8) would do the trick?
    > I lack the knowledge about alignment layout for archs that
    > need aligned accesses.
    > At a first glance, what I would except is that every buffer
    > has a base address aligned, no?

    Make it of the largest type that could appeat
    in a trace entry.

    I would use u64 so something like:

    u64 [FTRACE_MAX_PROFILE_SIZE / sizeof(u64)]


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