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shmem, thp: respect MADV_{NO,}HUGEPAGE for file mappings

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Let's wire up existing madvise() hugepage hints for file mappings.

MADV_HUGEPAGE advise shmem to allocate huge page on page fault in the
VMA.  It only has effect if the filesystem is mounted with huge=advise
or huge=within_size.

MADV_NOHUGEPAGE prevents hugepage from being allocated on page fault in
the VMA.  It doesn't prevent a huge page from being allocated by other
means, i.e.  page fault into different mapping or write(2) into file.

Link: http://lkml.kernel.org/r/1466021202-61880-31-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kirill A. Shutemov 2016-07-26 15:26:21 -07:00 committed by Linus Torvalds
parent 800d8c63b2
commit 657e3038c4
2 changed files with 22 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
mm/huge_memory.c
View File

@ -1830,7 +1830,7 @@ spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma)
return NULL;
}
#define VM_NO_THP (VM_SPECIAL | VM_HUGETLB | VM_SHARED | VM_MAYSHARE)
#define VM_NO_KHUGEPAGED (VM_SPECIAL | VM_HUGETLB | VM_SHARED | VM_MAYSHARE)
int hugepage_madvise(struct vm_area_struct *vma,
unsigned long *vm_flags, int advice)
@ -1846,11 +1846,6 @@ int hugepage_madvise(struct vm_area_struct *vma,
if (mm_has_pgste(vma->vm_mm))
return 0;
#endif
/*
* Be somewhat over-protective like KSM for now!
*/
if (*vm_flags & VM_NO_THP)
return -EINVAL;
*vm_flags &= ~VM_NOHUGEPAGE;
*vm_flags |= VM_HUGEPAGE;
/*
@ -1858,15 +1853,11 @@ int hugepage_madvise(struct vm_area_struct *vma,
* register it here without waiting a page fault that
* may not happen any time soon.
*/
if (unlikely(khugepaged_enter_vma_merge(vma, *vm_flags)))
if (!(*vm_flags & VM_NO_KHUGEPAGED) &&
khugepaged_enter_vma_merge(vma, *vm_flags))
return -ENOMEM;
break;
case MADV_NOHUGEPAGE:
/*
* Be somewhat over-protective like KSM for now!
*/
if (*vm_flags & VM_NO_THP)
return -EINVAL;
*vm_flags &= ~VM_HUGEPAGE;
*vm_flags |= VM_NOHUGEPAGE;
/*
@ -1974,7 +1965,7 @@ int khugepaged_enter_vma_merge(struct vm_area_struct *vma,
* page fault if needed.
*/
return 0;
if (vma->vm_ops || (vm_flags & VM_NO_THP))
if (vma->vm_ops || (vm_flags & VM_NO_KHUGEPAGED))
/* khugepaged not yet working on file or special mappings */
return 0;
hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
@ -2366,7 +2357,7 @@ static bool hugepage_vma_check(struct vm_area_struct *vma)
return false;
if (is_vma_temporary_stack(vma))
return false;
return !(vma->vm_flags & VM_NO_THP);
return !(vma->vm_flags & VM_NO_KHUGEPAGED);
}
/*

20
mm/shmem.c
View File

@ -101,6 +101,8 @@ struct shmem_falloc {
enum sgp_type {
SGP_READ, /* don't exceed i_size, don't allocate page */
SGP_CACHE, /* don't exceed i_size, may allocate page */
SGP_NOHUGE, /* like SGP_CACHE, but no huge pages */
SGP_HUGE, /* like SGP_CACHE, huge pages preferred */
SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
};
@ -1409,6 +1411,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
struct mem_cgroup *memcg;
struct page *page;
swp_entry_t swap;
enum sgp_type sgp_huge = sgp;
pgoff_t hindex = index;
int error;
int once = 0;
@ -1416,6 +1419,8 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
if (index > (MAX_LFS_FILESIZE >> PAGE_SHIFT))
return -EFBIG;
if (sgp == SGP_NOHUGE || sgp == SGP_HUGE)
sgp = SGP_CACHE;
repeat:
swap.val = 0;
page = find_lock_entry(mapping, index);
@ -1534,7 +1539,7 @@ repeat:
/* shmem_symlink() */
if (mapping->a_ops != &shmem_aops)
goto alloc_nohuge;
if (shmem_huge == SHMEM_HUGE_DENY)
if (shmem_huge == SHMEM_HUGE_DENY || sgp_huge == SGP_NOHUGE)
goto alloc_nohuge;
if (shmem_huge == SHMEM_HUGE_FORCE)
goto alloc_huge;
@ -1551,7 +1556,9 @@ repeat:
goto alloc_huge;
/* fallthrough */
case SHMEM_HUGE_ADVISE:
/* TODO: wire up fadvise()/madvise() */
if (sgp_huge == SGP_HUGE)
goto alloc_huge;
/* TODO: implement fadvise() hints */
goto alloc_nohuge;
}
@ -1680,6 +1687,7 @@ static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct inode *inode = file_inode(vma->vm_file);
gfp_t gfp = mapping_gfp_mask(inode->i_mapping);
enum sgp_type sgp;
int error;
int ret = VM_FAULT_LOCKED;
@ -1741,7 +1749,13 @@ static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
spin_unlock(&inode->i_lock);
}
error = shmem_getpage_gfp(inode, vmf->pgoff, &vmf->page, SGP_CACHE,
sgp = SGP_CACHE;
if (vma->vm_flags & VM_HUGEPAGE)
sgp = SGP_HUGE;
else if (vma->vm_flags & VM_NOHUGEPAGE)
sgp = SGP_NOHUGE;
error = shmem_getpage_gfp(inode, vmf->pgoff, &vmf->page, sgp,
gfp, vma->vm_mm, &ret);
if (error)
return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS);