Messages in this thread | | | Date | Mon, 9 Apr 2012 18:23:02 -0700 | Subject | Re: [patch] android, lowmemorykiller: remove task handoff notifier | From | Colin Cross <> |
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On Mon, Apr 9, 2012 at 4:56 PM, David Rientjes <rientjes@google.com> wrote: > The task handoff notifier leaks task_struct since it never gets freed > after the callback returns NOTIFY_OK, which means it is responsible for > doing so. > > It turns out the lowmemorykiller actually doesn't need this notifier at > all. It's used to prevent unnecessary killing by waiting for a thread to > exit as a result of lowmem_shrink(), however, it's possible to do this in > the same way the kernel oom killer works by setting TIF_MEMDIE and avoid > killing if we're still waiting for it to exit. > > The kernel oom killer will already automatically set TIF_MEMDIE for > threads that are attempting to allocate memory that have a fatal signal. > The thread selected by lowmem_shrink() will have such a signal after the > lowmemorykiller sends it a SIGKILL, so this won't result in an > unnecessary use of memory reserves for the thread to exit. > > This has the added benefit that we don't have to rely on CONFIG_PROFILING > to prevent needlessly killing tasks. > > Reported-by: werner <w.landgraf@ru.ru> > Cc: stable@vger.kernel.org > Signed-off-by: David Rientjes <rientjes@google.com> > --- > drivers/staging/android/lowmemorykiller.c | 48 +++++------------------------ > 1 file changed, 7 insertions(+), 41 deletions(-) >
I did a quick test to measure the difference in time spent inside lowmem_shrink with and without this patch, and they were about the same. So, Acked-by: Colin Cross <ccross@android.com> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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