• Cyrill Gorcunov's avatar
    procfs: add VmFlags field in smaps output · 834f82e2
    Cyrill Gorcunov authored
    
    
    During c/r sessions we've found that there is no way at the moment to
    fetch some VMA associated flags, such as mlock() and madvise().
    
    This leads us to a problem -- we don't know if we should call for mlock()
    and/or madvise() after restore on the vma area we're bringing back to
    life.
    
    This patch intorduces a new field into "smaps" output called VmFlags,
    where all set flags associated with the particular VMA is shown as two
    letter mnemonics.
    
    [ Strictly speaking for c/r we only need mlock/madvise bits but it has been
      said that providing just a few flags looks somehow inconsistent.  So all
      flags are here now. ]
    
    This feature is made available on CONFIG_CHECKPOINT_RESTORE=n kernels, as
    other applications may start to use these fields.
    
    The data is encoded in a somewhat awkward two letters mnemonic form, to
    encourage userspace to be prepared for fields being added or removed in
    the future.
    
    [a.p.zijlstra@chello.nl: props to use for_each_set_bit]
    [sfr@canb.auug.org.au: props to use array instead of struct]
    [akpm@linux-foundation.org: overall redesign and simplification]
    [akpm@linux-foundation.org: remove unneeded braces per sfr, avoid using bloaty for_each_set_bit()]
    Signed-off-by: default avatarCyrill Gorcunov <gorcunov@openvz.org>
    Cc: Pavel Emelyanov <xemul@parallels.com>
    Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Cc: Stephen Rothwell <sfr@canb.auug.org.au>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    834f82e2
proc.txt 75.7 KB