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    SubjectRe: [V2] android: binder: use VM_ALLOC to get vm area
    Hi, Greg

    2016-11-15 18:18 GMT+08:00 Greg KH <gregkh@linuxfoundation.org>:
    > On Tue, Nov 15, 2016 at 05:55:39PM +0800, Ganesh Mahendran wrote:
    >> VM_IOREMAP is used to access hardware through a mechanism called
    >> I/O mapped memory. Android binder is a IPC machanism which will
    >> not access I/O memory.
    >>
    >> Also VM_IOREMAP has alignment requiement which may not needed in
    >> binder.
    >> __get_vm_area_node()
    >> {
    >> ...
    >> if (flags & VM_IOREMAP)
    >> align = 1ul << clamp_t(int, fls_long(size),
    >> PAGE_SHIFT, IOREMAP_MAX_ORDER);
    >> ...
    >> }
    >>
    >> This patch use VM_ALLOC to get vm area.
    >>
    >> Below is the throughput test result:
    >>
    >> # ./binderThroughputTest -w 100
    >> I run this command 10 times:
    >> before after
    >> average iterations per sec: 11199.9 11886.9
    >>
    >> No performance regression found throgh binder test.
    >>
    >> Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
    >> ---
    >> drivers/android/binder.c | 2 +-
    >> 1 file changed, 1 insertion(+), 1 deletion(-)
    >
    > What changed from v1?

    Sorry for missing the change information.

    In V2, I run the binder test. And there is no side effect with this
    patch.

    >
    > Always list that below the --- line.

    Thanks for reminder.

    >
    > thanks,
    >
    > greg k-h

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