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| author | Baolin Wang <baolin.wang@linux.alibaba.com> | 2024-06-11 18:11:08 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-07-03 19:30:04 -0700 |
| commit | e7a2ab7b3bb5d87f99f2ea3d4481d52fc5ceb52d (patch) | |
| tree | a6b67ba8d429fb2f6cf63c9ee30917fe776a0fde /include/linux/huge_mm.h | |
| parent | 4b98995530b77a97912230d8e1564ba7738db19c (diff) | |
| download | linux-e7a2ab7b3bb5d87f99f2ea3d4481d52fc5ceb52d.tar.gz linux-e7a2ab7b3bb5d87f99f2ea3d4481d52fc5ceb52d.tar.bz2 linux-e7a2ab7b3bb5d87f99f2ea3d4481d52fc5ceb52d.zip | |
mm: shmem: add mTHP support for anonymous shmem
Commit 19eaf44954df adds multi-size THP (mTHP) for anonymous pages, that
can allow THP to be configured through the sysfs interface located at
'/sys/kernel/mm/transparent_hugepage/hugepage-XXkb/enabled'.
However, the anonymous shmem will ignore the anonymous mTHP rule
configured through the sysfs interface, and can only use the PMD-mapped
THP, that is not reasonable. Users expect to apply the mTHP rule for all
anonymous pages, including the anonymous shmem, in order to enjoy the
benefits of mTHP. For example, lower latency than PMD-mapped THP, smaller
memory bloat than PMD-mapped THP, contiguous PTEs on ARM architecture to
reduce TLB miss etc. In addition, the mTHP interfaces can be extended to
support all shmem/tmpfs scenarios in the future, especially for the shmem
mmap() case.
The primary strategy is similar to supporting anonymous mTHP. Introduce a
new interface '/mm/transparent_hugepage/hugepage-XXkb/shmem_enabled',
which can have almost the same values as the top-level
'/sys/kernel/mm/transparent_hugepage/shmem_enabled', with adding a new
additional "inherit" option and dropping the testing options 'force' and
'deny'. By default all sizes will be set to "never" except PMD size,
which is set to "inherit". This ensures backward compatibility with the
anonymous shmem enabled of the top level, meanwhile also allows
independent control of anonymous shmem enabled for each mTHP.
Link: https://lkml.kernel.org/r/65796c1e72e51e15f3410195b5c2d5b6c160d411.1718090413.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/huge_mm.h')
| -rw-r--r-- | include/linux/huge_mm.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 6a1edd752968..53b7a137f460 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -560,6 +560,16 @@ static inline bool thp_migration_supported(void) { return false; } + +static inline int highest_order(unsigned long orders) +{ + return 0; +} + +static inline int next_order(unsigned long *orders, int prev) +{ + return 0; +} #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ static inline int split_folio_to_list_to_order(struct folio *folio, |