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authorHuang Ying <ying.huang@intel.com>2018-08-17 15:49:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-17 16:20:32 -0700
commit14fef28414c365a979311821bbf1018a8290cc0f (patch)
treeacf988e3dce9ab19c6285a56d8266cf7698b3209 /mm
parent2a3cb8baef71e4dad4a6ec17f5f0db9e05f46a01 (diff)
downloadlinux-stericsson-14fef28414c365a979311821bbf1018a8290cc0f.tar.gz
mm, swap: make CONFIG_THP_SWAP depend on CONFIG_SWAP
CONFIG_THP_SWAP should depend on CONFIG_SWAP, because it's unreasonable to optimize swapping for THP (Transparent Huge Page) without basic swapping support. In original code, when CONFIG_SWAP=n and CONFIG_THP_SWAP=y, split_swap_cluster() will not be built because it is in swapfile.c, but it will be called in huge_memory.c. This doesn't trigger a build error in practice because the call site is enclosed by PageSwapCache(), which is defined to be constant 0 when CONFIG_SWAP=n. But this is fragile and should be fixed. The comments are fixed too to reflect the latest progress. Link: http://lkml.kernel.org/r/20180713021228.439-1-ying.huang@intel.com Fixes: 38d8b4e6bdc8 ("mm, THP, swap: delay splitting THP during swap out") Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Shaohua Li <shli@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Zi Yan <zi.yan@cs.rutgers.edu> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/Kconfig5
1 files changed, 3 insertions, 2 deletions
diff --git a/mm/Kconfig b/mm/Kconfig
index adfeae4decb4..a550635ea5c3 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -419,10 +419,11 @@ config ARCH_WANTS_THP_SWAP
config THP_SWAP
def_bool y
- depends on TRANSPARENT_HUGEPAGE && ARCH_WANTS_THP_SWAP
+ depends on TRANSPARENT_HUGEPAGE && ARCH_WANTS_THP_SWAP && SWAP
help
Swap transparent huge pages in one piece, without splitting.
- XXX: For now this only does clustered swap space allocation.
+ XXX: For now, swap cluster backing transparent huge page
+ will be split after swapout.
For selection by architectures with reasonable THP sizes.