tree a3fcf75191b7900043172d147fc7ed8ea97f3b4a
parent 8dd3557a52f0bc8c960307721da307370ccad6fd
author Hugh Dickins <hugh.dickins@tiscali.co.uk> 1260842359 -0800
committer Linus Torvalds <torvalds@linux-foundation.org> 1260895999 -0800

ksm: singly-linked rmap_list

Free up a pointer in struct rmap_item, by making the mm_slot's rmap_list a
singly-linked list: we always traverse that list sequentially, and we
don't even lose any prefetches (but should consider adding a few later).
Name it rmap_list throughout.

Do we need to free up that pointer?  Not immediately, and in the end, we
could continue to avoid it with a union; but having done the conversion,
let's keep it this way, since there's no downside, and maybe we'll want
more in future (struct rmap_item is a cache-friendly 32 bytes on 32-bit
and 64 bytes on 64-bit, so we shall want to avoid expanding it).

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>