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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2016-03-17 21:20:01 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-17 22:09:34 (GMT)
commitb97731992d00f09456726bfc5ab6641c07773038 (patch)
tree63c675c58a32cdf93ce30f57e14d8a2d9e1179e6 /include
parent99490f16f8b287a028306e4092cc85393907075f (diff)
downloadlinux-b97731992d00f09456726bfc5ab6641c07773038.tar.xz
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 'include')
-rw-r--r--include/linux/rmap.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index a07f42b..a5875e9 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -266,6 +266,7 @@ struct rmap_walk_control {
};
int rmap_walk(struct page *page, struct rmap_walk_control *rwc);
+int rmap_walk_locked(struct page *page, struct rmap_walk_control *rwc);
#else /* !CONFIG_MMU */