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Subject[PATCH 0/9] mm/rmap: unify rmap traversing functions through rmap_walk
Rmap traversing is used in five different cases, try_to_unmap(),
try_to_munlock(), page_referenced(), page_mkclean() and
remove_migration_ptes(). Each one implements its own traversing functions
for the cases, anon, file, ksm, respectively. These cause lots of duplications
and cause maintenance overhead. They also make codes being hard to understand
and error-prone. One example is hugepage handling. There is a code to compute
hugepage offset correctly in try_to_unmap_file(), but, there isn't a code
to compute hugepage offset in rmap_walk_file(). These are used pairwise
in migration context, but we missed to modify pairwise.

To overcome these drawbacks, we should unify these through one unified
function. I decide rmap_walk() as main function since it has no
unnecessity. And to control behavior of rmap_walk(), I introduce
struct rmap_walk_control having some function pointers. These makes
rmap_walk() working for their specific needs.

This patchset remove a lot of duplicated code as you can see in below
short-stat and kernel text size also decrease slightly.

text data bss dec hex filename
10640 1 16 10657 29a1 mm/rmap.o
10047 1 16 10064 2750 mm/rmap.o

13823 705 8288 22816 5920 mm/ksm.o
13199 705 8288 22192 56b0 mm/ksm.o


Joonsoo Kim (9):
mm/rmap: recompute pgoff for huge page
mm/rmap: factor nonlinear handling out of try_to_unmap_file()
mm/rmap: factor lock function out of rmap_walk_anon()
mm/rmap: make rmap_walk to get the rmap_walk_control argument
mm/rmap: extend rmap_walk_xxx() to cope with different cases
mm/rmap: use rmap_walk() in try_to_unmap()
mm/rmap: use rmap_walk() in try_to_munlock()
mm/rmap: use rmap_walk() in page_referenced()
mm/rmap: use rmap_walk() in page_mkclean()

include/linux/ksm.h | 15 +-
include/linux/rmap.h | 19 +-
mm/ksm.c | 116 +---------
mm/migrate.c | 7 +-
mm/rmap.c | 570 ++++++++++++++++++++++----------------------------
5 files changed, 286 insertions(+), 441 deletions(-)


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