• Kirill A. Shutemov's avatar
    page-flags: define PG_locked behavior on compound pages · 48c935ad
    Kirill A. Shutemov authored
    lock_page() must operate on the whole compound page.  It doesn't make
    much sense to lock part of compound page.  Change code to use head
    page's PG_locked, if tail page is passed.
    
    This patch also gets rid of custom helper functions --
    __set_page_locked() and __clear_page_locked().  They are replaced with
    helpers generated by __SETPAGEFLAG/__CLEARPAGEFLAG.  Tail pages to these
    helper would trigger VM_BUG_ON().
    
    SLUB uses PG_locked as a bit spin locked.  IIUC, tail pages should never
    appear there.  VM_BUG_ON() is added to make sure that this assumption is
    correct.
    
    [akpm@linux-foundation.org: fix fs/cifs/file.c]
    Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
    Cc: Andrea Arcangeli <aarcange@redhat.com>
    Cc: Hugh Dickins <hughd@google.com>
    Cc: Dave Hansen <dave.hansen@intel.com>
    Cc: Mel Gorman <mgorman@suse.de>
    Cc: Rik van Riel <riel@redhat.com>
    Cc: Vlastimil Babka <vbabka@suse.cz>
    Cc: Christoph Lameter <cl@linux.com>
    Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
    Cc: Steve Capper <steve.capper@linaro.org>
    Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
    Cc: Johannes Weiner <hannes@cmpxchg.org>
    Cc: Michal Hocko <mhocko@suse.cz>
    Cc: Jerome Marchand <jmarchan@redhat.com>
    Cc: Jérôme Glisse <jglisse@redhat.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    48c935ad
migrate.c 47.6 KB