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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2016-07-26 15:26:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-26 16:19:19 -0700
commite496cf3d782135c1cca0d154d4b924517ff58de0 (patch)
tree884ae0082c0b344dd9200b28ca087a3cc0973fed /mm/Kconfig
parentf3f0e1d2150b2b99da2cbdfaad000089efe9bf30 (diff)
downloadlinux-e496cf3d782135c1cca0d154d4b924517ff58de0.tar.bz2
thp: introduce CONFIG_TRANSPARENT_HUGE_PAGECACHE
For file mappings, we don't deposit page tables on THP allocation because it's not strictly required to implement split_huge_pmd(): we can just clear pmd and let following page faults to reconstruct the page table. But Power makes use of deposited page table to address MMU quirk. Let's hide THP page cache, including huge tmpfs, under separate config option, so it can be forbidden on Power. We can revert the patch later once solution for Power found. Link: http://lkml.kernel.org/r/1466021202-61880-36-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/Kconfig')
-rw-r--r--mm/Kconfig8
1 files changed, 8 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig
index 3e2daef3c946..3c81803b00a3 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -440,6 +440,14 @@ choice
endchoice
#
+# We don't deposit page tables on file THP mapping,
+# but Power makes use of them to address MMU quirk.
+#
+config TRANSPARENT_HUGE_PAGECACHE
+ def_bool y
+ depends on TRANSPARENT_HUGEPAGE && !PPC
+
+#
# UP and nommu archs use km based percpu allocator
#
config NEED_PER_CPU_KM