• Dave Hansen's avatar
    x86/mm: Fix swap entry comment and macro · ace7fab7
    Dave Hansen authored
    A recent patch changed the format of a swap PTE.
    
    The comment explaining the format of the swap PTE is wrong about
    the bits used for the swap type field.  Amusingly, the ASCII art
    and the patch description are correct, but the comment itself
    is wrong.
    
    As I was looking at this, I also noticed that the
    SWP_OFFSET_FIRST_BIT has an off-by-one error.  This does not
    really hurt anything.  It just wasted a bit of space in the PTE,
    giving us 2^59 bytes of addressable space in our swapfiles
    instead of 2^60.  But, it doesn't match with the comments, and it
    wastes a bit of space, so fix it.
    Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Brian Gerst <brgerst@gmail.com>
    Cc: Dave Hansen <dave@sr71.net>
    Cc: Denys Vlasenko <dvlasenk@redhat.com>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Josh Poimboeuf <jpoimboe@redhat.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Luis R. Rodriguez <mcgrof@suse.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Toshi Kani <toshi.kani@hp.com>
    Fixes: 00839ee3 ("x86/mm: Move swap offset/type up in PTE to work around erratum")
    Link: http://lkml.kernel.org/r/20160810172325.E56AD7DA@viggo.jf.intel.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    ace7fab7
pgtable_64.h 5.08 KB