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authorYang Shi <yang.shi@linux.alibaba.com>2019-04-19 04:17:04 +0800
committerJonathan Corbet <corbet@lwn.net>2019-04-19 12:48:06 -0600
commita496696ab56917baf813dacb4f4837f1ef516c50 (patch)
tree8a9ca097d381c297f668a51ebbd7247609c31d45 /Documentation
parentd8e8bcc3d8de530da43de16bf9cd89aa553ae290 (diff)
downloadlinux-a496696ab56917baf813dacb4f4837f1ef516c50.tar.bz2
doc: mm: migration doesn't use FOLL_SPLIT anymore
When demonstrating FOLL_SPLIT in transhuge document, migration is used as an example. But, since commit 94723aafb9e7 ("mm: unclutter THP migration"), the way of THP migration is totally changed. FOLL_SPLIT is not used by migration anymore due to the change. Remove the obsolete example to avoid confusion. Cc: Michal Hocko <mhocko@suse.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/vm/transhuge.rst8
1 files changed, 1 insertions, 7 deletions
diff --git a/Documentation/vm/transhuge.rst b/Documentation/vm/transhuge.rst
index a8cf6809e36e..8df380657430 100644
--- a/Documentation/vm/transhuge.rst
+++ b/Documentation/vm/transhuge.rst
@@ -55,13 +55,7 @@ prevent page from being split by anyone.
In case you can't handle compound pages if they're returned by
follow_page, the FOLL_SPLIT bit can be specified as parameter to
follow_page, so that it will split the hugepages before returning
-them. Migration for example passes FOLL_SPLIT as parameter to
-follow_page because it's not hugepage aware and in fact it can't work
-at all on hugetlbfs (but it instead works fine on transparent
-hugepages thanks to FOLL_SPLIT). migration simply can't deal with
-hugepages being returned (as it's not only checking the pfn of the
-page and pinning it during the copy but it pretends to migrate the
-memory in regular page sizes and with regular pte/pmd mappings).
+them.
Graceful fallback
=================