diff options
| author | Muchun Song <songmuchun@bytedance.com> | 2022-03-22 14:45:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-03-22 15:57:08 -0700 |
| commit | a6b40850c442bf996e729e1d441d3dbc37cea171 (patch) | |
| tree | cfc303b58ac086629bde47e00757a0b8e7ebc2e0 /include/linux/page-flags.h | |
| parent | e7d324850bfcb30df563d144c0363cc44595277d (diff) | |
mm: hugetlb: replace hugetlb_free_vmemmap_enabled with a static_key
The page_fixed_fake_head() is used throughout memory management and the
conditional check requires checking a global variable, although the
overhead of this check may be small, it increases when the memory cache
comes under pressure. Also, the global variable will not be modified
after system boot, so it is very appropriate to use static key machanism.
Link: https://lkml.kernel.org/r/20211101031651.75851-3-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Barry Song <song.bao.hua@hisilicon.com>
Cc: Bodeddula Balasubramaniam <bodeddub@amazon.com>
Cc: Chen Huang <chenhuang5@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/page-flags.h')
| -rw-r--r-- | include/linux/page-flags.h | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 111e453f23d2..340cb8156568 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -191,7 +191,14 @@ enum pageflags { #ifndef __GENERATING_BOUNDS_H #ifdef CONFIG_HUGETLB_PAGE_FREE_VMEMMAP -extern bool hugetlb_free_vmemmap_enabled; +DECLARE_STATIC_KEY_MAYBE(CONFIG_HUGETLB_PAGE_FREE_VMEMMAP_DEFAULT_ON, + hugetlb_free_vmemmap_enabled_key); + +static __always_inline bool hugetlb_free_vmemmap_enabled(void) +{ + return static_branch_maybe(CONFIG_HUGETLB_PAGE_FREE_VMEMMAP_DEFAULT_ON, + &hugetlb_free_vmemmap_enabled_key); +} /* * If the feature of freeing some vmemmap pages associated with each HugeTLB @@ -211,7 +218,7 @@ extern bool hugetlb_free_vmemmap_enabled; */ static __always_inline const struct page *page_fixed_fake_head(const struct page *page) { - if (!hugetlb_free_vmemmap_enabled) + if (!hugetlb_free_vmemmap_enabled()) return page; /* @@ -239,6 +246,11 @@ static inline const struct page *page_fixed_fake_head(const struct page *page) { return page; } + +static inline bool hugetlb_free_vmemmap_enabled(void) +{ + return false; +} #endif static __always_inline int page_is_fake_head(struct page *page) |