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| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2016-03-17 14:20:01 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-03-17 15:09:34 -0700 |
| commit | b97731992d00f09456726bfc5ab6641c07773038 (patch) | |
| tree | 63c675c58a32cdf93ce30f57e14d8a2d9e1179e6 /mm/huge_memory.c | |
| parent | 99490f16f8b287a028306e4092cc85393907075f (diff) | |
| download | blackbird-op-linux-b97731992d00f09456726bfc5ab6641c07773038.tar.gz blackbird-op-linux-b97731992d00f09456726bfc5ab6641c07773038.zip | |
rmap: introduce rmap_walk_locked()
This patchset rewrites freeze_page() and unfreeze_page() using
try_to_unmap() and remove_migration_ptes(). Result is much simpler, but
somewhat slower.
Migration 8GiB worth of PMD-mapped THP:
Baseline 20.21 +/- 0.393
Patched 20.73 +/- 0.082
Slowdown 1.03x
It's 3% slower, comparing to 14% in v1. I don't it should be a stopper.
Splitting of PTE-mapped pages slowed more. But this is not a common
case.
Migration 8GiB worth of PMD-mapped THP:
Baseline 20.39 +/- 0.225
Patched 22.43 +/- 0.496
Slowdown 1.10x
rmap_walk_locked() is the same as rmap_walk(), but the caller takes care
of the relevant rmap lock.
This is preparation for switching THP splitting from custom rmap walk in
freeze_page()/unfreeze_page() to the generic one.
There is no support for KSM pages for now: not clear which lock is
implied.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.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>
Diffstat (limited to 'mm/huge_memory.c')
0 files changed, 0 insertions, 0 deletions
