From: Hugh Dickins <hughd@xxxxxxxxxx> Subject: huge tmpfs: shmem_is_huge(vma, inode, index) Extend shmem_huge_enabled(vma) to shmem_is_huge(vma, inode, index), so that a consistent set of checks can be applied, even when the inode is accessed through read/write syscalls (with NULL vma) instead of mmaps (the index argument is seldom of interest, but required by mount option "huge=within_size"). Clean up and rearrange the checks a little. This then replaces the checks which shmem_fault() and shmem_getpage_gfp() were making, and eliminates the SGP_HUGE and SGP_NOHUGE modes. Replace a couple of 0s by explicit SHMEM_HUGE_NEVERs; and replace the obscure !shmem_mapping() symlink check by explicit S_ISLNK() - nothing else needs that symlink check, so leave it there in shmem_getpage_gfp(). Link: https://lkml.kernel.org/r/23a77889-2ddc-b030-75cd-44ca27fd4d1@xxxxxxxxxx Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx> Reviewed-by: Yang Shi <shy828301@xxxxxxxxx> Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxxx> Cc: Shakeel Butt <shakeelb@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/shmem_fs.h | 9 ++- mm/shmem.c | 84 +++++++++++-------------------------- 2 files changed, 31 insertions(+), 62 deletions(-) --- a/include/linux/shmem_fs.h~huge-tmpfs-shmem_is_hugevma-inode-index +++ a/include/linux/shmem_fs.h @@ -86,7 +86,12 @@ extern void shmem_truncate_range(struct extern int shmem_unuse(unsigned int type, bool frontswap, unsigned long *fs_pages_to_unuse); -extern bool shmem_huge_enabled(struct vm_area_struct *vma); +extern bool shmem_is_huge(struct vm_area_struct *vma, + struct inode *inode, pgoff_t index); +static inline bool shmem_huge_enabled(struct vm_area_struct *vma) +{ + return shmem_is_huge(vma, file_inode(vma->vm_file), vma->vm_pgoff); +} extern unsigned long shmem_swap_usage(struct vm_area_struct *vma); extern unsigned long shmem_partial_swap_usage(struct address_space *mapping, pgoff_t start, pgoff_t end); @@ -96,8 +101,6 @@ enum sgp_type { SGP_READ, /* don't exceed i_size, don't allocate page */ SGP_NOALLOC, /* similar, but fail on hole or use fallocated 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 */ }; --- a/mm/shmem.c~huge-tmpfs-shmem_is_hugevma-inode-index +++ a/mm/shmem.c @@ -471,39 +471,35 @@ static bool shmem_confirm_swap(struct ad #ifdef CONFIG_TRANSPARENT_HUGEPAGE /* ifdef here to avoid bloating shmem.o when not necessary */ -static int shmem_huge __read_mostly; +static int shmem_huge __read_mostly = SHMEM_HUGE_NEVER; -bool shmem_huge_enabled(struct vm_area_struct *vma) +bool shmem_is_huge(struct vm_area_struct *vma, + struct inode *inode, pgoff_t index) { - struct inode *inode = file_inode(vma->vm_file); - struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); loff_t i_size; - pgoff_t off; - if ((vma->vm_flags & VM_NOHUGEPAGE) || - test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) - return false; - if (shmem_huge == SHMEM_HUGE_FORCE) - return true; if (shmem_huge == SHMEM_HUGE_DENY) return false; - switch (sbinfo->huge) { - case SHMEM_HUGE_NEVER: + if (vma && ((vma->vm_flags & VM_NOHUGEPAGE) || + test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))) return false; + if (shmem_huge == SHMEM_HUGE_FORCE) + return true; + + switch (SHMEM_SB(inode->i_sb)->huge) { case SHMEM_HUGE_ALWAYS: return true; case SHMEM_HUGE_WITHIN_SIZE: - off = round_up(vma->vm_pgoff, HPAGE_PMD_NR); + index = round_up(index, HPAGE_PMD_NR); i_size = round_up(i_size_read(inode), PAGE_SIZE); - if (i_size >= HPAGE_PMD_SIZE && - i_size >> PAGE_SHIFT >= off) + if (i_size >= HPAGE_PMD_SIZE && (i_size >> PAGE_SHIFT) >= index) return true; fallthrough; case SHMEM_HUGE_ADVISE: - /* TODO: implement fadvise() hints */ - return (vma->vm_flags & VM_HUGEPAGE); + if (vma && (vma->vm_flags & VM_HUGEPAGE)) + return true; + fallthrough; default: - VM_BUG_ON(1); return false; } } @@ -677,6 +673,12 @@ static long shmem_unused_huge_count(stru #define shmem_huge SHMEM_HUGE_DENY +bool shmem_is_huge(struct vm_area_struct *vma, + struct inode *inode, pgoff_t index) +{ + return false; +} + static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo, struct shrink_control *sc, unsigned long nr_to_split) { @@ -1812,7 +1814,6 @@ static int shmem_getpage_gfp(struct inod struct shmem_sb_info *sbinfo; struct mm_struct *charge_mm; struct page *page; - enum sgp_type sgp_huge = sgp; pgoff_t hindex = index; gfp_t huge_gfp; int error; @@ -1821,8 +1822,6 @@ static int shmem_getpage_gfp(struct inod if (index > (MAX_LFS_FILESIZE >> PAGE_SHIFT)) return -EFBIG; - if (sgp == SGP_NOHUGE || sgp == SGP_HUGE) - sgp = SGP_CACHE; repeat: if (sgp <= SGP_CACHE && ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) { @@ -1886,36 +1885,12 @@ repeat: return 0; } - /* shmem_symlink() */ - if (!shmem_mapping(mapping)) - goto alloc_nohuge; - if (shmem_huge == SHMEM_HUGE_DENY || sgp_huge == SGP_NOHUGE) + /* Never use a huge page for shmem_symlink() */ + if (S_ISLNK(inode->i_mode)) goto alloc_nohuge; - if (shmem_huge == SHMEM_HUGE_FORCE) - goto alloc_huge; - switch (sbinfo->huge) { - case SHMEM_HUGE_NEVER: + if (!shmem_is_huge(vma, inode, index)) goto alloc_nohuge; - case SHMEM_HUGE_WITHIN_SIZE: { - loff_t i_size; - pgoff_t off; - - off = round_up(index, HPAGE_PMD_NR); - i_size = round_up(i_size_read(inode), PAGE_SIZE); - if (i_size >= HPAGE_PMD_SIZE && - i_size >> PAGE_SHIFT >= off) - goto alloc_huge; - fallthrough; - } - case SHMEM_HUGE_ADVISE: - if (sgp_huge == SGP_HUGE) - goto alloc_huge; - /* TODO: implement fadvise() hints */ - goto alloc_nohuge; - } - -alloc_huge: huge_gfp = vma_thp_gfp_mask(vma); huge_gfp = limit_gfp_mask(huge_gfp, gfp); page = shmem_alloc_and_acct_page(huge_gfp, inode, index, true); @@ -2071,7 +2046,6 @@ static vm_fault_t shmem_fault(struct vm_ struct vm_area_struct *vma = vmf->vma; struct inode *inode = file_inode(vma->vm_file); gfp_t gfp = mapping_gfp_mask(inode->i_mapping); - enum sgp_type sgp; int err; vm_fault_t ret = VM_FAULT_LOCKED; @@ -2134,15 +2108,7 @@ static vm_fault_t shmem_fault(struct vm_ spin_unlock(&inode->i_lock); } - sgp = SGP_CACHE; - - if ((vma->vm_flags & VM_NOHUGEPAGE) || - test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) - sgp = SGP_NOHUGE; - else if (vma->vm_flags & VM_HUGEPAGE) - sgp = SGP_HUGE; - - err = shmem_getpage_gfp(inode, vmf->pgoff, &vmf->page, sgp, + err = shmem_getpage_gfp(inode, vmf->pgoff, &vmf->page, SGP_CACHE, gfp, vma, vmf, &ret); if (err) return vmf_error(err); @@ -3950,7 +3916,7 @@ int __init shmem_init(void) if (has_transparent_hugepage() && shmem_huge > SHMEM_HUGE_DENY) SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge; else - shmem_huge = 0; /* just in case it was patched */ + shmem_huge = SHMEM_HUGE_NEVER; /* just in case it was patched */ #endif return 0; _
