forked from luck/tmp_suning_uos_patched
hugetlb: add MAP_HUGETLB for mmaping pseudo-anonymous huge page regions
Add a flag for mmap that will be used to request a huge page region that will look like anonymous memory to userspace. This is accomplished by using a file on the internal vfsmount. MAP_HUGETLB is a modifier of MAP_ANONYMOUS and so must be specified with it. The region will behave the same as a MAP_ANONYMOUS region using small pages. [akpm@linux-foundation.org: fix arch definitions of MAP_HUGETLB] Signed-off-by: Eric B Munson <ebmunson@us.ibm.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Adam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -112,12 +112,19 @@ static inline void hugetlb_report_meminfo(struct seq_file *m)
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#endif /* !CONFIG_HUGETLB_PAGE */
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#define HUGETLB_ANON_FILE "anon_hugepage"
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enum {
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/*
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* The file will be used as an shm file so shmfs accounting rules
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* apply
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*/
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HUGETLB_SHMFS_INODE = 1,
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/*
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* The file is being created on the internal vfs mount and shmfs
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* accounting rules do not apply
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*/
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HUGETLB_ANONHUGE_INODE = 2,
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};
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#ifdef CONFIG_HUGETLBFS
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18
mm/mmap.c
18
mm/mmap.c
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@ -949,6 +949,24 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
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if (mm->map_count > sysctl_max_map_count)
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return -ENOMEM;
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if (flags & MAP_HUGETLB) {
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struct user_struct *user = NULL;
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if (file)
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return -EINVAL;
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/*
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* VM_NORESERVE is used because the reservations will be
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* taken when vm_ops->mmap() is called
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* A dummy user value is used because we are not locking
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* memory so no accounting is necessary
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*/
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len = ALIGN(len, huge_page_size(&default_hstate));
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file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, VM_NORESERVE,
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&user, HUGETLB_ANONHUGE_INODE);
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if (IS_ERR(file))
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return PTR_ERR(file);
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}
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/* Obtain the address to map to. we verify (or select) it and ensure
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* that it represents a valid section of the address space.
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*/
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