lkml.org 
[lkml]   [2011]   [Nov]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: WARNING: at mm/slub.c:3357, kernel BUG at mm/slub.c:3413
    On 2011.11.22 at 09:27 +0100, Eric Dumazet wrote:
    > Le mardi 22 novembre 2011 à 08:48 +0100, Eric Dumazet a écrit :
    >
    > > For x86, I wonder if our !X86_FEATURE_CX16 support is correct on SMP
    > > machines.
    > >
    >
    >
    > By the way, I wonder why we still emit this_cpu_cmpxchg16b_emu() code
    > and calls when compiling a kernel for a cpu implementing cmpxchg16b
    >
    > (CONFIG_MCORE2=y)

    Yeah, it's strange (CONFIG_MK8):

    ffffffff811058b0 <__kmalloc>:
    ...
    ffffffff8110594f: 48 8d 4a 04 lea 0x4(%rdx),%rcx
    ffffffff81105953: 49 8b 1c 04 mov (%r12,%rax,1),%rbx
    ffffffff81105957: 4c 89 e0 mov %r12,%rax
    ffffffff8110595a: e8 11 70 10 00 callq ffffffff8120c970 <this_cpu_cmpxchg16b_emu>
    ffffffff8110595f: 66 66 90 data32 xchg %ax,%ax
    ffffffff81105962: 84 c0 test %al,%al
    ffffffff81105964: 74 c6 je ffffffff8110592c <__kmalloc+0x7c>
    ...

    There is a comment in arch/x86/include/asm/percpu.h:

    * Pretty complex macro to generate cmpxchg16 instruction. The instruction
    * is not supported on early AMD64 processors so we must be able to emulate
    * it in software. The address used in the cmpxchg16 instruction must be
    * aligned to a 16 byte boundary.
    --
    Markus
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2011-11-23 08:17    [W:3.614 / U:0.332 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site