![Chen, Kenneth W](/assets/img/avatar_default.png)
Following up with the work on shared page table done by Dave McCracken. This set of patch target shared page table for hugetlb memory only. The shared page table is particular useful in the situation of large number of independent processes sharing large shared memory segments. In the normal page case, the amount of memory saved from process' page table is quite significant. For hugetlb, the saving on page table memory is not the primary objective (as hugetlb itself already cuts down page table overhead significantly), instead, the purpose of using shared page table on hugetlb is to allow faster TLB refill and smaller cache pollution upon TLB miss. With PT sharing, pte entries are shared among hundreds of processes, the cache consumption used by all the page table is smaller and in return, application gets much higher cache hit ratio. One other effect is that cache hit ratio with hardware page walker hitting on pte in cache will be higher and this helps to reduce tlb miss latency. These two effects contribute to higher application performance. Signed-off-by: Ken Chen <kenneth.w.chen@intel.com> Acked-by: Hugh Dickins <hugh@veritas.com> Cc: Dave McCracken <dmccr@us.ibm.com> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Adam Litke <agl@us.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
187 lines
5.7 KiB
C
187 lines
5.7 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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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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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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int hugetlb_reserve_pages(struct inode *inode, long from, long to);
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void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed);
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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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int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep);
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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 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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#endif
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#ifndef ARCH_HAS_HUGETLB_FREE_PGD_RANGE
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#define hugetlb_free_pgd_range free_pgd_range
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#else
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void hugetlb_free_pgd_range(struct mmu_gather **tlb, unsigned long addr,
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unsigned long end, unsigned long floor,
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unsigned long ceiling);
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#endif
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#ifndef ARCH_HAS_PREPARE_HUGEPAGE_RANGE
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/*
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* If the arch doesn't supply something else, assume that hugepage
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* size aligned regions are ok without further preparation.
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*/
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static inline int prepare_hugepage_range(unsigned long addr, unsigned long len,
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pgoff_t pgoff)
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{
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if (pgoff & (~HPAGE_MASK >> PAGE_SHIFT))
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return -EINVAL;
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if (len & ~HPAGE_MASK)
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return -EINVAL;
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if (addr & ~HPAGE_MASK)
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return -EINVAL;
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return 0;
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}
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#else
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int prepare_hugepage_range(unsigned long addr, unsigned long len,
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pgoff_t pgoff);
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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 prepare_hugepage_range(addr,len,pgoff) (-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) ({BUG(); 0; })
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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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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 const 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_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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