• Paul E. McKenney's avatar
    doc: Update memory-barriers.txt for read-to-write dependencies · 66ce3a4d
    Paul E. McKenney authored
    The memory-barriers.txt document contains an obsolete passage stating that
    smp_read_barrier_depends() is required to force ordering for read-to-write
    dependencies.  We now know that this is not required, even for DEC Alpha.
    This commit therefore updates this passage to state that read-to-write
    dependencies are respected even without smp_read_barrier_depends().
    Reported-by: default avatarLance Roy <ldr709@gmail.com>
    Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
    Cc: David Howells <dhowells@redhat.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Jonathan Corbet <corbet@lwn.net>
    Cc: Alan Stern <stern@rowland.harvard.edu>
    Cc: Andrea Parri <parri.andrea@gmail.com>
    Cc: Jade Alglave <j.alglave@ucl.ac.uk>
    Cc: Luc Maranget <luc.maranget@inria.fr>
    [ paulmck: Reference control-dependencies sections and use WRITE_ONCE()
      per Will Deacon.  Correctly place split-cache paragraph while there. ]
    Acked-by: default avatarWill Deacon <will.deacon@arm.com>
memory-barriers.txt 116 KB