[lkml]   [2009]   [Feb]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: smp.c && barriers (Was: [PATCH 1/4] generic-smp: remove single ipi fallback for smp_call_function_many())
On Wed, 2009-02-18 at 05:59 -0800, Nick Piggin wrote:
> You're saying the problem is in generic_exec_single because I've
> removed the smp_mb that inadvertently also serialises memory with
> the x2apic on x86?


> Indeed that could cause problems on some architectures which I
> had hoped to avoid. So the patch is probably better off to first
> add the smp_mb() to arch_send_call_function_xxx arch code, unless
> it is immediately obvious or confirmed by arch maintainer that
> such barrier is not required.

For x2apic specific operations we should add the smp_mb() sequence. But
we need to make sure that we don't end up doing it twice (once in
generic code and another in arch code) for all the ipi paths.


 \ /
  Last update: 2009-02-18 19:47    [from the cache]
©2003-2014 Jasper Spaans. hosted at Digital Ocean