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    Subject[PATCH -tip] x86: atomic64: inline atomic64_read()
    Now atomic64_read() is light weight (no register pressure and
    small icache), we can inline it again.

    Also use "=&A" constraint instead of "+A" to avoid warning
    about unitialized 'res' variable. (gcc had to force 0 in eax/edx)


    $ size vmlinux.prev vmlinux.after
    text data bss dec hex filename
    4908667 451676 1684868 7045211 6b805b vmlinux.prev
    4908651 451676 1684868 7045195 6b804b vmlinux.after

    Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
    ---
    arch/x86/include/asm/atomic_32.h | 15 +++++++++++++++
    arch/x86/lib/atomic64_32.c | 21 ---------------------
    2 files changed, 15 insertions(+), 21 deletions(-)

    diff --git a/arch/x86/include/asm/atomic_32.h b/arch/x86/include/asm/atomic_32.h
    index aa045de..0332041 100644
    --- a/arch/x86/include/asm/atomic_32.h
    +++ b/arch/x86/include/asm/atomic_32.h
    @@ -304,6 +304,21 @@ extern void atomic64_set(atomic64_t *ptr, u64 new_val);
    *
    * Atomically reads the value of @ptr and returns it.
    */
    +static inline u64 atomic64_read(atomic64_t *ptr)
    +{
    + u64 res;
    +
    + asm volatile(
    + "mov %%ebx, %%eax\n\t"
    + "mov %%ecx, %%edx\n\t"
    + LOCK_PREFIX "cmpxchg8b %1\n"
    + : "=&A" (res)
    + : "m" (*ptr)
    + );
    +
    + return res;
    +}
    +
    extern u64 atomic64_read(atomic64_t *ptr);

    /**
    diff --git a/arch/x86/lib/atomic64_32.c b/arch/x86/lib/atomic64_32.c
    index cd11803..cb51226 100644
    --- a/arch/x86/lib/atomic64_32.c
    +++ b/arch/x86/lib/atomic64_32.c
    @@ -55,27 +55,6 @@ void atomic64_set(atomic64_t *ptr, u64 new_val)
    }

    /**
    - * atomic64_read - read atomic64 variable
    - * @ptr: pointer to type atomic64_t
    - *
    - * Atomically reads the value of @ptr and returns it.
    - */
    -u64 atomic64_read(atomic64_t *ptr)
    -{
    - u64 res;
    -
    - asm volatile(
    - "mov %%ebx, %%eax\n\t"
    - "mov %%ecx, %%edx\n\t"
    - LOCK_PREFIX "cmpxchg8b %1\n"
    - : "+A" (res)
    - : "m" (*ptr)
    - );
    -
    - return res;
    -}
    -
    -/**
    * atomic64_add_return - add and return
    * @delta: integer value to add
    * @ptr: pointer to type atomic64_t

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      Last update: 2009-07-03 16:53    [W:0.021 / U:30.260 seconds]
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