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    SubjectRe: [RFC PATCH 5/6 v4] perf: Fix race in callchains
    On Tue, Aug 17, 2010 at 03:34:06AM +0200, Frederic Weisbecker wrote:

    > Now that software events don't have interrupt disabled anymore in
    > the event path, callchains can nest on any context. So seperating
    > nmi and others contexts in two buffers has become racy.
    > Fix this by providing one buffer per nesting level. Given the size
    > of the callchain entries (2040 bytes * 4), we now need to allocate
    > them dynamically.
    > v2: Fixed put_callchain_entry call after recursion.
    > Fix the type of the recursion, it must be an array.
    > v3: Use a manual pr cpu allocation (temporary solution until NMIs
    > can safely access vmalloc'ed memory).

    It would be nice to make these allocations node-local.

    Also, I see that we're allocating 4 buffers per cpu on powerpc when we
    strictly only need 3, but I don't suppose that really matters.


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