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| author | Muchun Song <songmuchun@bytedance.com> | 2021-06-30 18:48:28 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-06-30 20:47:26 -0700 |
| commit | e6d41f12df0efcaa6e30b575d40f2529024cfce9 (patch) | |
| tree | 9d547e73faa1f232a63284f3656a82a44630197d /mm | |
| parent | 2d7a21715f25122779e2bed17db8c57aa01e922f (diff) | |
| download | lwn-e6d41f12df0efcaa6e30b575d40f2529024cfce9.tar.gz lwn-e6d41f12df0efcaa6e30b575d40f2529024cfce9.zip | |
mm: hugetlb: introduce CONFIG_HUGETLB_PAGE_FREE_VMEMMAP_DEFAULT_ON
When using HUGETLB_PAGE_FREE_VMEMMAP, the freeing unused vmemmap pages
associated with each HugeTLB page is default off. Now the vmemmap is PMD
mapped. So there is no side effect when this feature is enabled with no
HugeTLB pages in the system. Someone may want to enable this feature in
the compiler time instead of using boot command line. So add a config to
make it default on when someone do not want to enable it via command line.
Link: https://lkml.kernel.org/r/20210616094915.34432-4-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Chen Huang <chenhuang5@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
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 'mm')
| -rw-r--r-- | mm/hugetlb_vmemmap.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c index 06802056f296..c540c21e26f5 100644 --- a/mm/hugetlb_vmemmap.c +++ b/mm/hugetlb_vmemmap.c @@ -182,7 +182,7 @@ #define RESERVE_VMEMMAP_NR 2U #define RESERVE_VMEMMAP_SIZE (RESERVE_VMEMMAP_NR << PAGE_SHIFT) -bool hugetlb_free_vmemmap_enabled; +bool hugetlb_free_vmemmap_enabled = IS_ENABLED(CONFIG_HUGETLB_PAGE_FREE_VMEMMAP_DEFAULT_ON); static int __init early_hugetlb_free_vmemmap_param(char *buf) { @@ -197,7 +197,9 @@ static int __init early_hugetlb_free_vmemmap_param(char *buf) if (!strcmp(buf, "on")) hugetlb_free_vmemmap_enabled = true; - else if (strcmp(buf, "off")) + else if (!strcmp(buf, "off")) + hugetlb_free_vmemmap_enabled = false; + else return -EINVAL; return 0; |