b45b5bd65f
These days, hugepages are demand-allocated at first fault time. There's a somewhat dubious (and racy) heuristic when making a new mmap() to check if there are enough available hugepages to fully satisfy that mapping. A particularly obvious case where the heuristic breaks down is where a process maps its hugepages not as a single chunk, but as a bunch of individually mmap()ed (or shmat()ed) blocks without touching and instantiating the pages in between allocations. In this case the size of each block is compared against the total number of available hugepages. It's thus easy for the process to become overcommitted, because each block mapping will succeed, although the total number of hugepages required by all blocks exceeds the number available. In particular, this defeats such a program which will detect a mapping failure and adjust its hugepage usage downward accordingly. The patch below addresses this problem, by strictly reserving a number of physical hugepages for hugepage inodes which have been mapped, but not instatiated. MAP_SHARED mappings are thus "safe" - they will fail on mmap(), not later with an OOM SIGKILL. MAP_PRIVATE mappings can still trigger an OOM. (Actually SHARED mappings can technically still OOM, but only if the sysadmin explicitly reduces the hugepage pool between mapping and instantiation) This patch appears to address the problem at hand - it allows DB2 to start correctly, for instance, which previously suffered the failure described above. This patch causes no regressions on the libhugetblfs testsuite, and makes a test (designed to catch this problem) pass which previously failed (ppc64, POWER5). Signed-off-by: David Gibson <dwg@au1.ibm.com> Cc: William Lee Irwin III <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
176 lines
5.5 KiB
C
176 lines
5.5 KiB
C
#ifndef _LINUX_HUGETLB_H
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#define _LINUX_HUGETLB_H
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#ifdef CONFIG_HUGETLB_PAGE
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#include <linux/mempolicy.h>
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#include <asm/tlbflush.h>
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struct ctl_table;
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static inline int is_vm_hugetlb_page(struct vm_area_struct *vma)
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{
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return vma->vm_flags & VM_HUGETLB;
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}
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int hugetlb_sysctl_handler(struct ctl_table *, int, struct file *, void __user *, size_t *, loff_t *);
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int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_area_struct *);
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int follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *, struct page **, struct vm_area_struct **, unsigned long *, int *, int);
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void unmap_hugepage_range(struct vm_area_struct *, unsigned long, unsigned long);
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int hugetlb_prefault(struct address_space *, struct vm_area_struct *);
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int hugetlb_report_meminfo(char *);
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int hugetlb_report_node_meminfo(int, char *);
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unsigned long hugetlb_total_pages(void);
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struct page *alloc_huge_page(struct vm_area_struct *, unsigned long);
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void free_huge_page(struct page *);
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int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
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unsigned long address, int write_access);
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extern unsigned long max_huge_pages;
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extern const unsigned long hugetlb_zero, hugetlb_infinity;
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extern int sysctl_hugetlb_shm_group;
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/* arch callbacks */
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pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr);
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pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr);
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struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
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int write);
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struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
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pmd_t *pmd, int write);
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int is_aligned_hugepage_range(unsigned long addr, unsigned long len);
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int pmd_huge(pmd_t pmd);
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void hugetlb_change_protection(struct vm_area_struct *vma,
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unsigned long address, unsigned long end, pgprot_t newprot);
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#ifndef ARCH_HAS_HUGEPAGE_ONLY_RANGE
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#define is_hugepage_only_range(mm, addr, len) 0
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#define hugetlb_free_pgd_range(tlb, addr, end, floor, ceiling) \
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do { } while (0)
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#endif
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#ifndef ARCH_HAS_PREPARE_HUGEPAGE_RANGE
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#define prepare_hugepage_range(addr, len) \
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is_aligned_hugepage_range(addr, len)
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#else
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int prepare_hugepage_range(unsigned long addr, unsigned long len);
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#endif
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#ifndef ARCH_HAS_SETCLEAR_HUGE_PTE
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#define set_huge_pte_at(mm, addr, ptep, pte) set_pte_at(mm, addr, ptep, pte)
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#define huge_ptep_get_and_clear(mm, addr, ptep) ptep_get_and_clear(mm, addr, ptep)
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#else
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void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
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pte_t *ptep, pte_t pte);
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pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
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pte_t *ptep);
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#endif
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#ifndef ARCH_HAS_HUGETLB_PREFAULT_HOOK
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#define hugetlb_prefault_arch_hook(mm) do { } while (0)
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#else
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void hugetlb_prefault_arch_hook(struct mm_struct *mm);
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#endif
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#else /* !CONFIG_HUGETLB_PAGE */
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static inline int is_vm_hugetlb_page(struct vm_area_struct *vma)
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{
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return 0;
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}
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static inline unsigned long hugetlb_total_pages(void)
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{
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return 0;
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}
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#define follow_hugetlb_page(m,v,p,vs,a,b,i) ({ BUG(); 0; })
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#define follow_huge_addr(mm, addr, write) ERR_PTR(-EINVAL)
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#define copy_hugetlb_page_range(src, dst, vma) ({ BUG(); 0; })
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#define hugetlb_prefault(mapping, vma) ({ BUG(); 0; })
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#define unmap_hugepage_range(vma, start, end) BUG()
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#define hugetlb_report_meminfo(buf) 0
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#define hugetlb_report_node_meminfo(n, buf) 0
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#define follow_huge_pmd(mm, addr, pmd, write) NULL
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#define is_aligned_hugepage_range(addr, len) 0
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#define prepare_hugepage_range(addr, len) (-EINVAL)
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#define pmd_huge(x) 0
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#define is_hugepage_only_range(mm, addr, len) 0
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#define hugetlb_free_pgd_range(tlb, addr, end, floor, ceiling) \
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do { } while (0)
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#define alloc_huge_page(vma, addr) ({ NULL; })
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#define free_huge_page(p) ({ (void)(p); BUG(); })
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#define hugetlb_fault(mm, vma, addr, write) ({ BUG(); 0; })
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#define hugetlb_change_protection(vma, address, end, newprot)
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#ifndef HPAGE_MASK
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#define HPAGE_MASK PAGE_MASK /* Keep the compiler happy */
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#define HPAGE_SIZE PAGE_SIZE
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#endif
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#endif /* !CONFIG_HUGETLB_PAGE */
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#ifdef CONFIG_HUGETLBFS
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struct hugetlbfs_config {
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uid_t uid;
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gid_t gid;
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umode_t mode;
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long nr_blocks;
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long nr_inodes;
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};
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struct hugetlbfs_sb_info {
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long max_blocks; /* blocks allowed */
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long free_blocks; /* blocks free */
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long max_inodes; /* inodes allowed */
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long free_inodes; /* inodes free */
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spinlock_t stat_lock;
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};
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struct hugetlbfs_inode_info {
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struct shared_policy policy;
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/* Protected by the (global) hugetlb_lock */
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unsigned long prereserved_hpages;
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struct inode vfs_inode;
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};
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static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
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{
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return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
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}
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static inline struct hugetlbfs_sb_info *HUGETLBFS_SB(struct super_block *sb)
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{
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return sb->s_fs_info;
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}
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extern struct file_operations hugetlbfs_file_operations;
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extern struct vm_operations_struct hugetlb_vm_ops;
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struct file *hugetlb_zero_setup(size_t);
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int hugetlb_extend_reservation(struct hugetlbfs_inode_info *info,
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unsigned long atleast_hpages);
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void hugetlb_truncate_reservation(struct hugetlbfs_inode_info *info,
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unsigned long atmost_hpages);
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int hugetlb_get_quota(struct address_space *mapping);
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void hugetlb_put_quota(struct address_space *mapping);
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static inline int is_file_hugepages(struct file *file)
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{
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return file->f_op == &hugetlbfs_file_operations;
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}
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static inline void set_file_hugepages(struct file *file)
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{
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file->f_op = &hugetlbfs_file_operations;
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}
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#else /* !CONFIG_HUGETLBFS */
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#define is_file_hugepages(file) 0
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#define set_file_hugepages(file) BUG()
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#define hugetlb_zero_setup(size) ERR_PTR(-ENOSYS)
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#endif /* !CONFIG_HUGETLBFS */
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#endif /* _LINUX_HUGETLB_H */
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