[lkml]   [2007]   [Sep]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH] Fix preemptible lazy mode bug
    On Thu, 2007-08-23 at 22:46 -0700, Zachary Amsden wrote:
    > I recently sent off a fix for lazy vmalloc faults which can happen under
    > paravirt when lazy mode is enabled. Unfortunately, I jumped the gun a
    > bit on fixing this. I neglected to notice that since the new call to
    > flush the MMU update queue is called from the page fault handler, it can
    > be pre-empted. Both VMI and Xen use per-cpu variables to track lazy
    > mode state, as all previous calls to set, disable, or flush lazy mode
    > happened from a non-preemptable state.

    Hi Zach,

    I don't think this patch does anything. The flush is because we want
    the just-completed "set_pte" to have immediate effect, so if preempt is
    enabled we're already screwed because we can be moved between set_pte
    and the arch_flush_lazy_mmu_mode() call.

    Now, where's the problem caller? By my reading or rc4, vmalloc faults
    are fixed up before enabling interrupts.


    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2007-09-05 22:41    [W:0.025 / U:1.672 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site