lkml.org 
[lkml]   [2011]   [Aug]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH v2 4/5] trace: Make removal of ring buffer pages atomic
    On Mon, Aug 22, 2011 at 8:27 PM, Steven Rostedt <rostedt@goodmis.org> 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


    \
     
     \ /
      Last update: 2011-08-23 21:01    [W:6.715 / U:0.020 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site