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Shutemov" , Miaohe Lin , Mike Kravetz , Michal Hocko , Rik van Riel , Matthew Wilcox , Linux Kernel Mailing List , Linux MM Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=gmail.com header.s=20161025 header.b=Vuhg74MR; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf13.hostedemail.com: domain of shy828301@gmail.com designates 209.85.218.45 as permitted sender) smtp.mailfrom=shy828301@gmail.com X-Stat-Signature: wxjrc5dfaw1yi7yq6u1n3djpcttha6y9 X-Rspamd-Queue-Id: 3F51B1018425 X-Rspamd-Server: rspam05 X-HE-Tag: 1629231385-629349 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Aug 17, 2021 at 1:19 AM Hugh Dickins wrote: > > 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(). > > Signed-off-by: Hugh Dickins Reviewed-by: Yang Shi > --- > include/linux/shmem_fs.h | 9 +++-- > mm/shmem.c | 84 ++++++++++++---------------------------- > 2 files changed, 31 insertions(+), 62 deletions(-) > > diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h > index 7d97b15a2f7a..60c6e4eac275 100644 > --- a/include/linux/shmem_fs.h > +++ b/include/linux/shmem_fs.h > @@ -86,7 +86,12 @@ extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end); > 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 */ > }; > diff --git a/mm/shmem.c b/mm/shmem.c > index 226ac3a911e9..56ee56b1cab6 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -474,39 +474,35 @@ static bool shmem_confirm_swap(struct address_space *mapping, > #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; > } > } > @@ -680,6 +676,12 @@ static long shmem_unused_huge_count(struct super_block *sb, > > #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) > { > @@ -1829,7 +1831,6 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, > 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; > @@ -1838,8 +1839,6 @@ 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: > if (sgp <= SGP_CACHE && > ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) { > @@ -1903,36 +1902,12 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, > 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); > @@ -2088,7 +2063,6 @@ static vm_fault_t shmem_fault(struct vm_fault *vmf) > 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; > > @@ -2151,15 +2125,7 @@ static vm_fault_t shmem_fault(struct vm_fault *vmf) > 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); > @@ -3966,7 +3932,7 @@ 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; > > -- > 2.26.2 >