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    perf/core, x86: Add PERF_SAMPLE_PHYS_ADDR · fc7ce9c7
    Kan Liang 提交于
    For understanding how the workload maps to memory channels and hardware
    behavior, it's very important to collect address maps with physical
    addresses. For example, 3D XPoint access can only be found by filtering
    the physical address.
    
    Add a new sample type for physical address.
    
    perf already has a facility to collect data virtual address. This patch
    introduces a function to convert the virtual address to physical address.
    The function is quite generic and can be extended to any architecture as
    long as a virtual address is provided.
    
     - For kernel direct mapping addresses, virt_to_phys is used to convert
       the virtual addresses to physical address.
    
     - For user virtual addresses, __get_user_pages_fast is used to walk the
       pages tables for user physical address.
    
     - This does not work for vmalloc addresses right now. These are not
       resolved, but code to do that could be added.
    
    The new sample type requires collecting the virtual address. The
    virtual address will not be output unless SAMPLE_ADDR is applied.
    
    For security, the physical address can only be exposed to root or
    privileged user.
    Tested-by: NMadhavan Srinivasan <maddy@linux.vnet.ibm.com>
    Signed-off-by: NKan Liang <kan.liang@intel.com>
    Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
    Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
    Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Stephane Eranian <eranian@google.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Vince Weaver <vincent.weaver@maine.edu>
    Cc: acme@kernel.org
    Cc: mpe@ellerman.id.au
    Link: http://lkml.kernel.org/r/1503967969-48278-1-git-send-email-kan.liang@intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
    fc7ce9c7
core-book3s.c 56.0 KB