• Ingo Molnar's avatar
    x86/mm: Don't flush the TLB on #WP pmd fixups · 5e4bf1a5
    Ingo Molnar authored
    If we have a write protection #PF and fix up the pmd then the
    hugetlb code [the only user of pmdp_set_access_flags], in its
    do_huge_pmd_wp_page() page fault resolution function calls
    pmdp_set_access_flags() to mark the pmd permissive again,
    and flushes the TLB.
    
    This TLB flush is unnecessary: a flush on #PF is guaranteed on
    most (all?) x86 CPUs, and even in the worst-case we'll generate
    a spurious fault.
    
    So remove it.
    
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Cc: Paul Turner <pjt@google.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
    Cc: Andrea Arcangeli <aarcange@redhat.com>
    Cc: Rik van Riel <riel@redhat.com>
    Cc: Johannes Weiner <hannes@cmpxchg.org>
    Cc: Christoph Lameter <cl@linux.com>
    Cc: Mel Gorman <mgorman@suse.de>
    Cc: Hugh Dickins <hughd@google.com>
    Link: http://lkml.kernel.org/r/20121120120251.GA15742@gmail.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    5e4bf1a5
pgtable.c 10.2 KB