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authorMuchun Song <songmuchun@bytedance.com>2021-07-01 04:48:22 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-07-01 06:47:26 +0300
commit3bc2b6a725963bb1b441356873da890e397c1a3f (patch)
treeb5d12b3ec2cb06dd17d8f635af2490d1e8ccfaa7 /include/linux/mm.h
parent8cc5fcbb5be814c115085549b700e473685b11e9 (diff)
downloadlinux-3bc2b6a725963bb1b441356873da890e397c1a3f.tar.xz
mm: sparsemem: split the huge PMD mapping of vmemmap pages
Patch series "Split huge PMD mapping of vmemmap pages", v4. In order to reduce the difficulty of code review in series[1]. We disable huge PMD mapping of vmemmap pages when that feature is enabled. In this series, we do not disable huge PMD mapping of vmemmap pages anymore. We will split huge PMD mapping when needed. When HugeTLB pages are freed from the pool we do not attempt coalasce and move back to a PMD mapping because it is much more complex. [1] https://lore.kernel.org/linux-doc/20210510030027.56044-1-songmuchun@bytedance.com/ This patch (of 3): In [1], PMD mappings of vmemmap pages were disabled if the the feature hugetlb_free_vmemmap was enabled. This was done to simplify the initial implementation of vmmemap freeing for hugetlb pages. Now, remove this simplification by allowing PMD mapping and switching to PTE mappings as needed for allocated hugetlb pages. When a hugetlb page is allocated, the vmemmap page tables are walked to free vmemmap pages. During this walk, split huge PMD mappings to PTE mappings as required. In the unlikely case PTE pages can not be allocated, return error(ENOMEM) and do not optimize vmemmap of the hugetlb page. When HugeTLB pages are freed from the pool, we do not attempt to coalesce and move back to a PMD mapping because it is much more complex. [1] https://lkml.kernel.org/r/20210510030027.56044-8-songmuchun@bytedance.com Link: https://lkml.kernel.org/r/20210616094915.34432-1-songmuchun@bytedance.com Link: https://lkml.kernel.org/r/20210616094915.34432-2-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: David Hildenbrand <david@redhat.com> Cc: Chen Huang <chenhuang5@huawei.com> Cc: Jonathan Corbet <corbet@lwn.net> 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/mm.h')
-rw-r--r--include/linux/mm.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 706bee98d965..aa875dacd9c3 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3076,8 +3076,8 @@ static inline void print_vma_addr(char *prefix, unsigned long rip)
}
#endif
-void vmemmap_remap_free(unsigned long start, unsigned long end,
- unsigned long reuse);
+int vmemmap_remap_free(unsigned long start, unsigned long end,
+ unsigned long reuse);
int vmemmap_remap_alloc(unsigned long start, unsigned long end,
unsigned long reuse, gfp_t gfp_mask);