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authorMina Almasry <almasrymina@google.com>2021-11-05 23:41:40 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-06 23:30:39 +0300
commit550a7d60bd5e35a56942dba6d8a26752beb26c9f (patch)
treeb45281ee0741008551143172645a791a3d9e23d9 /include/linux/hugetlb.h
parentbd3400ea173fb611cdf2030d03620185ff6c0b0e (diff)
downloadlinux-550a7d60bd5e35a56942dba6d8a26752beb26c9f.tar.xz
mm, hugepages: add mremap() support for hugepage backed vma
Support mremap() for hugepage backed vma segment by simply repositioning page table entries. The page table entries are repositioned to the new virtual address on mremap(). Hugetlb mremap() support is of course generic; my motivating use case is a library (hugepage_text), which reloads the ELF text of executables in hugepages. This significantly increases the execution performance of said executables. Restrict the mremap operation on hugepages to up to the size of the original mapping as the underlying hugetlb reservation is not yet capable of handling remapping to a larger size. During the mremap() operation we detect pmd_share'd mappings and we unshare those during the mremap(). On access and fault the sharing is established again. Link: https://lkml.kernel.org/r/20211013195825.3058275-1-almasrymina@google.com Signed-off-by: Mina Almasry <almasrymina@google.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Ken Chen <kenchen@google.com> Cc: Chris Kennelly <ckennelly@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Kirill Shutemov <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/hugetlb.h')
-rw-r--r--include/linux/hugetlb.h19
1 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 2bddd6c38204..c0a20781b28e 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -124,6 +124,7 @@ struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
void hugepage_put_subpool(struct hugepage_subpool *spool);
void reset_vma_resv_huge_pages(struct vm_area_struct *vma);
+void clear_vma_resv_huge_pages(struct vm_area_struct *vma);
int hugetlb_sysctl_handler(struct ctl_table *, int, void *, size_t *, loff_t *);
int hugetlb_overcommit_handler(struct ctl_table *, int, void *, size_t *,
loff_t *);
@@ -132,6 +133,10 @@ int hugetlb_treat_movable_handler(struct ctl_table *, int, void *, size_t *,
int hugetlb_mempolicy_sysctl_handler(struct ctl_table *, int, void *, size_t *,
loff_t *);
+int move_hugetlb_page_tables(struct vm_area_struct *vma,
+ struct vm_area_struct *new_vma,
+ unsigned long old_addr, unsigned long new_addr,
+ unsigned long len);
int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_area_struct *);
long follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *,
struct page **, struct vm_area_struct **,
@@ -215,6 +220,10 @@ static inline void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
{
}
+static inline void clear_vma_resv_huge_pages(struct vm_area_struct *vma)
+{
+}
+
static inline unsigned long hugetlb_total_pages(void)
{
return 0;
@@ -262,6 +271,16 @@ static inline int copy_hugetlb_page_range(struct mm_struct *dst,
return 0;
}
+static inline int move_hugetlb_page_tables(struct vm_area_struct *vma,
+ struct vm_area_struct *new_vma,
+ unsigned long old_addr,
+ unsigned long new_addr,
+ unsigned long len)
+{
+ BUG();
+ return 0;
+}
+
static inline void hugetlb_report_meminfo(struct seq_file *m)
{
}