The patch titled
Subject: mm/memcontrol.c: make the walk_page_range() limit obvious
has been added to the -mm tree. Its filename is
mm-memcontrol-make-the-walk_page_range-limit-obvious.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-make-the-walk_page_range-limit-obvious.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-make-the-walk_page_range-limit-obvious.patch
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------------------------------------------------------
From: James Morse <james.morse@xxxxxxx>
Subject: mm/memcontrol.c: make the walk_page_range() limit obvious
Trying to walk all of virtual memory requires architecture specific
knowledge. On x86_64, addresses must be sign extended from bit 48,
whereas on arm64 the top VA_BITS of address space have their own set of
page tables.
mem_cgroup_count_precharge() and mem_cgroup_move_charge() both call
walk_page_range() on the range 0 to ~0UL, neither provide a pte_hole
callback, which causes the current implementation to skip non-vma regions.
As this call only expects to walk user address space, make it walk
0 to 'highest_vm_end'.
Link: http://lkml.kernel.org/r/1472655897-22532-1-git-send-email-james.morse@xxxxxxx
Signed-off-by: James Morse <james.morse@xxxxxxx>
Acked-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff -puN mm/memcontrol.c~mm-memcontrol-make-the-walk_page_range-limit-obvious mm/memcontrol.c
--- a/mm/memcontrol.c~mm-memcontrol-make-the-walk_page_range-limit-obvious
+++ a/mm/memcontrol.c
@@ -4668,7 +4668,8 @@ static unsigned long mem_cgroup_count_pr
.mm = mm,
};
down_read(&mm->mmap_sem);
- walk_page_range(0, ~0UL, &mem_cgroup_count_precharge_walk);
+ walk_page_range(0, mm->highest_vm_end,
+ &mem_cgroup_count_precharge_walk);
up_read(&mm->mmap_sem);
precharge = mc.precharge;
@@ -4956,7 +4957,8 @@ retry:
* When we have consumed all precharges and failed in doing
* additional charge, the page walk just aborts.
*/
- walk_page_range(0, ~0UL, &mem_cgroup_move_charge_walk);
+ walk_page_range(0, mc.mm->highest_vm_end, &mem_cgroup_move_charge_walk);
+
up_read(&mc.mm->mmap_sem);
atomic_dec(&mc.from->moving_account);
}
_
Patches currently in -mm which might be from james.morse@xxxxxxx are
mm-pagewalk-fix-the-comment-for-test_walk.patch
mm-proc-make-the-task_mmu-walk_page_range-limit-in-clear_refs_write-obvious.patch
mm-memcontrol-make-the-walk_page_range-limit-obvious.patch
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