1. 08 10月, 2014 1 次提交
  2. 01 10月, 2009 1 次提交
    • A
      x86: Provide an alternative() based cmpxchg64() · 79e1dd05
      Arjan van de Ven 提交于
      cmpxchg64() today generates, to quote Linus, "barf bag" code.
      
      cmpxchg64() is about to get used in the scheduler to fix a bug there,
      but it's a prerequisite that cmpxchg64() first be made non-sucking.
      
      This patch turns cmpxchg64() into an efficient implementation that
      uses the alternative() mechanism to just use the raw instruction on
      all modern systems.
      
      Note: the fallback is NOT smp safe, just like the current fallback
      is not SMP safe. (Interested parties with i486 based SMP systems
      are welcome to submit fix patches for that.)
      Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
      Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
      [ fixed asm constraint bug ]
      Fixed-by: NEric Dumazet <eric.dumazet@gmail.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: John Stultz <johnstul@us.ibm.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      LKML-Reference: <20090930170754.0886ff2e@infradead.org>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      79e1dd05