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    SubjectRe: [PATCH v2 4/5] trace: Make removal of ring buffer pages atomic
    On Mon, Aug 22, 2011 at 8:27 PM, Steven Rostedt <> wrote:
    > On Tue, 2011-08-16 at 14:46 -0700, Vaibhav Nagarnaik wrote:
    >> This patch adds the capability to remove pages from a ring buffer
    >> without destroying any existing data in it.
    >> This is done by removing the pages after the tail page. This makes sure
    >> that first all the empty pages in the ring buffer are removed. If the
    >> head page is one in the list of pages to be removed, then the page after
    >> the removed ones is made the head page. This removes the oldest data
    >> from the ring buffer and keeps the latest data around to be read.
    >> To do this in a non-racey manner, tracing is stopped for a very short
    >> time while the pages to be removed are identified and unlinked from the
    >> ring buffer. The pages are freed after the tracing is restarted to
    >> minimize the time needed to stop tracing.
    >> The context in which the pages from the per-cpu ring buffer are removed
    >> runs on the respective CPU. This minimizes the events not traced to only
    >> NMI trace contexts.
    > Could you do the same with this patch, as this one fails to build as
    > well. And probably should check patch 5 while your at it.
    > -- Steve

    I have corrected both the patches. I will make sure that I add
    'allyesconfig' and 'allnoconfig' build targets also in my work flow to
    avoid such issues.

    Vaibhav Nagarnaik

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      Last update: 2011-08-23 21:01    [W:0.021 / U:24.672 seconds]
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