• Tejun Heo's avatar
    x86-64, NUMA: Revert NUMA affine page table allocation · f8911250
    Tejun Heo authored
    This patch reverts NUMA affine page table allocation added by commit
    1411e0ec (x86-64, numa: Put pgtable to local node memory).
    
    The commit made an undocumented change where the kernel linear mapping
    strictly follows intersection of e820 memory map and NUMA
    configuration.  If the physical memory configuration has holes or NUMA
    nodes are not properly aligned, this leads to using unnecessarily
    smaller mapping size which leads to increased TLB pressure.  For
    details,
    
      http://thread.gmane.org/gmane.linux.kernel/1104672
    
    Patches to fix the problem have been proposed but the underlying code
    needs more cleanup and the approach itself seems a bit heavy handed
    and it has been determined to revert the feature for now and come back
    to it in the next developement cycle.
    
      http://thread.gmane.org/gmane.linux.kernel/1105959
    
    As init_memory_mapping_high() callsites have been consolidated since
    the commit, reverting is done manually.  Also, the RED-PEN comment in
    arch/x86/mm/init.c is not restored as the problem no longer exists
    with memblock based top-down early memory allocation.
    Signed-off-by: default avatarTejun Heo <tj@kernel.org>
    Cc: Yinghai Lu <yinghai@kernel.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    f8911250
init_64.c 23.8 KB