From 84e8e54e2ed9d857c4e10a7e487532203385249c Mon Sep 17 00:00:00 2001 From: Ying Sun Date: Wed, 6 Sep 2023 12:50:12 +0800 Subject: mm/shmem: remove dead code can not be satisfied by "(CONFIG_SHMEM)&&(!(CONFIG_SHMEM))" MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The value of “.fs_flags” in line 4608 is a dead code which will never be implemented，because its conditions of line 47 "#ifdef CONFIG_SHMEM" and line 4607 are mutually exclusive. It is recommended to delete redundant code. Link: https://lkml.kernel.org/r/20230906045012.14999-1-sunying@nj.iscas.ac.cn Signed-off-by: Ying Sun Suggested-by: Yanjie Ren Signed-off-by: Andrew Morton --- mm/shmem.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'mm/shmem.c') diff --git a/mm/shmem.c b/mm/shmem.c index 69595d341882..8539d39ec9a3 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -4585,11 +4585,7 @@ static struct file_system_type shmem_fs_type = { .parameters = shmem_fs_parameters, #endif .kill_sb = kill_litter_super, -#ifdef CONFIG_SHMEM .fs_flags = FS_USERNS_MOUNT | FS_ALLOW_IDMAP, -#else - .fs_flags = FS_USERNS_MOUNT, -#endif }; void __init shmem_init(void) -- cgit v1.2.3 From e3e1a5067fd2f1b3f4f7c651f5b33082962d1aa1 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Fri, 29 Sep 2023 20:26:53 -0700 Subject: shmem: remove vma arg from shmem_get_folio_gfp() The vma is already there in vmf->vma, so no need for a separate arg. Link: https://lkml.kernel.org/r/d9ce6f65-a2ed-48f4-4299-fdb0544875c5@google.com Signed-off-by: Hugh Dickins Reviewed-by: Jan Kara Cc: Axel Rasmussen Cc: Carlos Maiolino Cc: Christian Brauner Cc: Chuck Lever Cc: Darrick J. Wong Cc: Dave Chinner Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Tim Chen Signed-off-by: Andrew Morton --- mm/shmem.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) (limited to 'mm/shmem.c') diff --git a/mm/shmem.c b/mm/shmem.c index 8539d39ec9a3..dfa7e544a99d 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1921,14 +1921,13 @@ unlock: * vm. If we swap it in we mark it dirty since we also free the swap * entry since a page cannot live in both the swap and page cache. * - * vma, vmf, and fault_type are only supplied by shmem_fault: - * otherwise they are NULL. + * vmf and fault_type are only supplied by shmem_fault: otherwise they are NULL. */ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, struct folio **foliop, enum sgp_type sgp, gfp_t gfp, - struct vm_area_struct *vma, struct vm_fault *vmf, - vm_fault_t *fault_type) + struct vm_fault *vmf, vm_fault_t *fault_type) { + struct vm_area_struct *vma = vmf ? vmf->vma : NULL; struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); struct shmem_sb_info *sbinfo; @@ -2141,7 +2140,7 @@ int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop, enum sgp_type sgp) { return shmem_get_folio_gfp(inode, index, foliop, sgp, - mapping_gfp_mask(inode->i_mapping), NULL, NULL, NULL); + mapping_gfp_mask(inode->i_mapping), NULL, NULL); } /* @@ -2225,7 +2224,7 @@ static vm_fault_t shmem_fault(struct vm_fault *vmf) } err = shmem_get_folio_gfp(inode, vmf->pgoff, &folio, SGP_CACHE, - gfp, vma, vmf, &ret); + gfp, vmf, &ret); if (err) return vmf_error(err); if (folio) @@ -4893,7 +4892,7 @@ struct folio *shmem_read_folio_gfp(struct address_space *mapping, BUG_ON(!shmem_mapping(mapping)); error = shmem_get_folio_gfp(inode, index, &folio, SGP_CACHE, - gfp, NULL, NULL, NULL); + gfp, NULL, NULL); if (error) return ERR_PTR(error); -- cgit v1.2.3 From f0a9ad1d4d9ba3c694bca91d8d67be9a4a33b902 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Fri, 29 Sep 2023 20:27:53 -0700 Subject: shmem: factor shmem_falloc_wait() out of shmem_fault() That Trinity livelock shmem_falloc avoidance block is unlikely, and a distraction from the proper business of shmem_fault(): separate it out. (This used to help compilers save stack on the fault path too, but both gcc and clang nowadays seem to make better choices anyway.) Link: https://lkml.kernel.org/r/6fe379a4-6176-9225-9263-fe60d2633c0@google.com Signed-off-by: Hugh Dickins Reviewed-by: Jan Kara Cc: Axel Rasmussen Cc: Carlos Maiolino Cc: Christian Brauner Cc: Chuck Lever Cc: Darrick J. Wong Cc: Dave Chinner Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Tim Chen Signed-off-by: Andrew Morton --- mm/shmem.c | 126 +++++++++++++++++++++++++++++++++---------------------------- 1 file changed, 69 insertions(+), 57 deletions(-) (limited to 'mm/shmem.c') diff --git a/mm/shmem.c b/mm/shmem.c index dfa7e544a99d..0aa8889c76f2 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2148,87 +2148,99 @@ int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop, * entry unconditionally - even if something else had already woken the * target. */ -static int synchronous_wake_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) +static int synchronous_wake_function(wait_queue_entry_t *wait, + unsigned int mode, int sync, void *key) { int ret = default_wake_function(wait, mode, sync, key); list_del_init(&wait->entry); return ret; } +/* + * Trinity finds that probing a hole which tmpfs is punching can + * prevent the hole-punch from ever completing: which in turn + * locks writers out with its hold on i_rwsem. So refrain from + * faulting pages into the hole while it's being punched. Although + * shmem_undo_range() does remove the additions, it may be unable to + * keep up, as each new page needs its own unmap_mapping_range() call, + * and the i_mmap tree grows ever slower to scan if new vmas are added. + * + * It does not matter if we sometimes reach this check just before the + * hole-punch begins, so that one fault then races with the punch: + * we just need to make racing faults a rare case. + * + * The implementation below would be much simpler if we just used a + * standard mutex or completion: but we cannot take i_rwsem in fault, + * and bloating every shmem inode for this unlikely case would be sad. + */ +static vm_fault_t shmem_falloc_wait(struct vm_fault *vmf, struct inode *inode) +{ + struct shmem_falloc *shmem_falloc; + struct file *fpin = NULL; + vm_fault_t ret = 0; + + spin_lock(&inode->i_lock); + shmem_falloc = inode->i_private; + if (shmem_falloc && + shmem_falloc->waitq && + vmf->pgoff >= shmem_falloc->start && + vmf->pgoff < shmem_falloc->next) { + wait_queue_head_t *shmem_falloc_waitq; + DEFINE_WAIT_FUNC(shmem_fault_wait, synchronous_wake_function); + + ret = VM_FAULT_NOPAGE; + fpin = maybe_unlock_mmap_for_io(vmf, NULL); + shmem_falloc_waitq = shmem_falloc->waitq; + prepare_to_wait(shmem_falloc_waitq, &shmem_fault_wait, + TASK_UNINTERRUPTIBLE); + spin_unlock(&inode->i_lock); + schedule(); + + /* + * shmem_falloc_waitq points into the shmem_fallocate() + * stack of the hole-punching task: shmem_falloc_waitq + * is usually invalid by the time we reach here, but + * finish_wait() does not dereference it in that case; + * though i_lock needed lest racing with wake_up_all(). + */ + spin_lock(&inode->i_lock); + finish_wait(shmem_falloc_waitq, &shmem_fault_wait); + } + spin_unlock(&inode->i_lock); + if (fpin) { + fput(fpin); + ret = VM_FAULT_RETRY; + } + return ret; +} + 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); + struct inode *inode = file_inode(vmf->vma->vm_file); gfp_t gfp = mapping_gfp_mask(inode->i_mapping); struct folio *folio = NULL; + vm_fault_t ret = 0; int err; - vm_fault_t ret = VM_FAULT_LOCKED; /* * Trinity finds that probing a hole which tmpfs is punching can - * prevent the hole-punch from ever completing: which in turn - * locks writers out with its hold on i_rwsem. So refrain from - * faulting pages into the hole while it's being punched. Although - * shmem_undo_range() does remove the additions, it may be unable to - * keep up, as each new page needs its own unmap_mapping_range() call, - * and the i_mmap tree grows ever slower to scan if new vmas are added. - * - * It does not matter if we sometimes reach this check just before the - * hole-punch begins, so that one fault then races with the punch: - * we just need to make racing faults a rare case. - * - * The implementation below would be much simpler if we just used a - * standard mutex or completion: but we cannot take i_rwsem in fault, - * and bloating every shmem inode for this unlikely case would be sad. + * prevent the hole-punch from ever completing: noted in i_private. */ if (unlikely(inode->i_private)) { - struct shmem_falloc *shmem_falloc; - - spin_lock(&inode->i_lock); - shmem_falloc = inode->i_private; - if (shmem_falloc && - shmem_falloc->waitq && - vmf->pgoff >= shmem_falloc->start && - vmf->pgoff < shmem_falloc->next) { - struct file *fpin; - wait_queue_head_t *shmem_falloc_waitq; - DEFINE_WAIT_FUNC(shmem_fault_wait, synchronous_wake_function); - - ret = VM_FAULT_NOPAGE; - fpin = maybe_unlock_mmap_for_io(vmf, NULL); - if (fpin) - ret = VM_FAULT_RETRY; - - shmem_falloc_waitq = shmem_falloc->waitq; - prepare_to_wait(shmem_falloc_waitq, &shmem_fault_wait, - TASK_UNINTERRUPTIBLE); - spin_unlock(&inode->i_lock); - schedule(); - - /* - * shmem_falloc_waitq points into the shmem_fallocate() - * stack of the hole-punching task: shmem_falloc_waitq - * is usually invalid by the time we reach here, but - * finish_wait() does not dereference it in that case; - * though i_lock needed lest racing with wake_up_all(). - */ - spin_lock(&inode->i_lock); - finish_wait(shmem_falloc_waitq, &shmem_fault_wait); - spin_unlock(&inode->i_lock); - - if (fpin) - fput(fpin); + ret = shmem_falloc_wait(vmf, inode); + if (ret) return ret; - } - spin_unlock(&inode->i_lock); } + WARN_ON_ONCE(vmf->page != NULL); err = shmem_get_folio_gfp(inode, vmf->pgoff, &folio, SGP_CACHE, gfp, vmf, &ret); if (err) return vmf_error(err); - if (folio) + if (folio) { vmf->page = folio_file_page(folio, vmf->pgoff); + ret |= VM_FAULT_LOCKED; + } return ret; } -- cgit v1.2.3 From 9be7d5b06648b808989e99c5d0bea1be47c5a384 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Fri, 29 Sep 2023 20:28:50 -0700 Subject: shmem: trivial tidyups, removing extra blank lines, etc Mostly removing a few superfluous blank lines, joining short arglines, imposing some 80-column observance, correcting a couple of comments. None of it more interesting than deleting a repeated INIT_LIST_HEAD(). Link: https://lkml.kernel.org/r/b3983d28-5d3f-8649-36af-b819285d7a9e@google.com Signed-off-by: Hugh Dickins Reviewed-by: Jan Kara Cc: Axel Rasmussen Cc: Carlos Maiolino Cc: Christian Brauner Cc: Chuck Lever Cc: Darrick J. Wong Cc: Dave Chinner Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Tim Chen Signed-off-by: Andrew Morton --- mm/shmem.c | 56 +++++++++++++++++++++----------------------------------- 1 file changed, 21 insertions(+), 35 deletions(-) (limited to 'mm/shmem.c') diff --git a/mm/shmem.c b/mm/shmem.c index 0aa8889c76f2..3540fc598848 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -756,7 +756,7 @@ static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo, #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ /* - * Like filemap_add_folio, but error if expected item has gone. + * Somewhat like filemap_add_folio, but error if expected item has gone. */ static int shmem_add_to_page_cache(struct folio *folio, struct address_space *mapping, @@ -825,7 +825,7 @@ error: } /* - * Like delete_from_page_cache, but substitutes swap for @folio. + * Somewhat like filemap_remove_folio, but substitutes swap for @folio. */ static void shmem_delete_from_page_cache(struct folio *folio, void *radswap) { @@ -887,7 +887,6 @@ unsigned long shmem_partial_swap_usage(struct address_space *mapping, cond_resched_rcu(); } } - rcu_read_unlock(); return swapped << PAGE_SHIFT; @@ -1213,7 +1212,6 @@ static int shmem_setattr(struct mnt_idmap *idmap, if (i_uid_needs_update(idmap, attr, inode) || i_gid_needs_update(idmap, attr, inode)) { error = dquot_transfer(idmap, inode, attr); - if (error) return error; } @@ -2456,7 +2454,6 @@ static struct inode *__shmem_get_inode(struct mnt_idmap *idmap, if (err) return ERR_PTR(err); - inode = new_inode(sb); if (!inode) { shmem_free_inode(sb, 0); @@ -2481,11 +2478,10 @@ static struct inode *__shmem_get_inode(struct mnt_idmap *idmap, shmem_set_inode_flags(inode, info->fsflags); INIT_LIST_HEAD(&info->shrinklist); INIT_LIST_HEAD(&info->swaplist); - INIT_LIST_HEAD(&info->swaplist); - if (sbinfo->noswap) - mapping_set_unevictable(inode->i_mapping); simple_xattrs_init(&info->xattrs); cache_no_acl(inode); + if (sbinfo->noswap) + mapping_set_unevictable(inode->i_mapping); mapping_set_large_folios(inode->i_mapping); switch (mode & S_IFMT) { @@ -2697,7 +2693,6 @@ shmem_write_begin(struct file *file, struct address_space *mapping, } ret = shmem_get_folio(inode, index, &folio, SGP_WRITE); - if (ret) return ret; @@ -3229,8 +3224,7 @@ shmem_mknod(struct mnt_idmap *idmap, struct inode *dir, error = simple_acl_create(dir, inode); if (error) goto out_iput; - error = security_inode_init_security(inode, dir, - &dentry->d_name, + error = security_inode_init_security(inode, dir, &dentry->d_name, shmem_initxattrs, NULL); if (error && error != -EOPNOTSUPP) goto out_iput; @@ -3259,14 +3253,11 @@ shmem_tmpfile(struct mnt_idmap *idmap, struct inode *dir, int error; inode = shmem_get_inode(idmap, dir->i_sb, dir, mode, 0, VM_NORESERVE); - if (IS_ERR(inode)) { error = PTR_ERR(inode); goto err_out; } - - error = security_inode_init_security(inode, dir, - NULL, + error = security_inode_init_security(inode, dir, NULL, shmem_initxattrs, NULL); if (error && error != -EOPNOTSUPP) goto out_iput; @@ -3303,7 +3294,8 @@ static int shmem_create(struct mnt_idmap *idmap, struct inode *dir, /* * Link a file.. */ -static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) +static int shmem_link(struct dentry *old_dentry, struct inode *dir, + struct dentry *dentry) { struct inode *inode = d_inode(old_dentry); int ret = 0; @@ -3334,7 +3326,7 @@ static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentr inode_inc_iversion(dir); inc_nlink(inode); ihold(inode); /* New dentry reference */ - dget(dentry); /* Extra pinning count for the created dentry */ + dget(dentry); /* Extra pinning count for the created dentry */ d_instantiate(dentry, inode); out: return ret; @@ -3354,7 +3346,7 @@ static int shmem_unlink(struct inode *dir, struct dentry *dentry) inode_set_ctime_current(inode)); inode_inc_iversion(dir); drop_nlink(inode); - dput(dentry); /* Undo the count from "create" - this does all the work */ + dput(dentry); /* Undo the count from "create" - does all the work */ return 0; } @@ -3464,7 +3456,6 @@ static int shmem_symlink(struct mnt_idmap *idmap, struct inode *dir, inode = shmem_get_inode(idmap, dir->i_sb, dir, S_IFLNK | 0777, 0, VM_NORESERVE); - if (IS_ERR(inode)) return PTR_ERR(inode); @@ -3518,8 +3509,7 @@ static void shmem_put_link(void *arg) folio_put(arg); } -static const char *shmem_get_link(struct dentry *dentry, - struct inode *inode, +static const char *shmem_get_link(struct dentry *dentry, struct inode *inode, struct delayed_call *done) { struct folio *folio = NULL; @@ -3593,8 +3583,7 @@ static int shmem_fileattr_set(struct mnt_idmap *idmap, * Callback for security_inode_init_security() for acquiring xattrs. */ static int shmem_initxattrs(struct inode *inode, - const struct xattr *xattr_array, - void *fs_info) + const struct xattr *xattr_array, void *fs_info) { struct shmem_inode_info *info = SHMEM_I(inode); struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); @@ -3778,7 +3767,6 @@ static struct dentry *shmem_find_alias(struct inode *inode) return alias ?: d_find_any_alias(inode); } - static struct dentry *shmem_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len, int fh_type) { @@ -4362,8 +4350,8 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc) } #endif /* CONFIG_TMPFS_QUOTA */ - inode = shmem_get_inode(&nop_mnt_idmap, sb, NULL, S_IFDIR | sbinfo->mode, 0, - VM_NORESERVE); + inode = shmem_get_inode(&nop_mnt_idmap, sb, NULL, + S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); if (IS_ERR(inode)) { error = PTR_ERR(inode); goto failed; @@ -4662,11 +4650,9 @@ static ssize_t shmem_enabled_show(struct kobject *kobj, for (i = 0; i < ARRAY_SIZE(values); i++) { len += sysfs_emit_at(buf, len, - shmem_huge == values[i] ? "%s[%s]" : "%s%s", - i ? " " : "", - shmem_format_huge(values[i])); + shmem_huge == values[i] ? "%s[%s]" : "%s%s", + i ? " " : "", shmem_format_huge(values[i])); } - len += sysfs_emit_at(buf, len, "\n"); return len; @@ -4763,8 +4749,9 @@ EXPORT_SYMBOL_GPL(shmem_truncate_range); #define shmem_acct_size(flags, size) 0 #define shmem_unacct_size(flags, size) do {} while (0) -static inline struct inode *shmem_get_inode(struct mnt_idmap *idmap, struct super_block *sb, struct inode *dir, - umode_t mode, dev_t dev, unsigned long flags) +static inline struct inode *shmem_get_inode(struct mnt_idmap *idmap, + struct super_block *sb, struct inode *dir, + umode_t mode, dev_t dev, unsigned long flags) { struct inode *inode = ramfs_get_inode(sb, dir, mode, dev); return inode ? inode : ERR_PTR(-ENOSPC); @@ -4774,8 +4761,8 @@ static inline struct inode *shmem_get_inode(struct mnt_idmap *idmap, struct supe /* common code */ -static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, loff_t size, - unsigned long flags, unsigned int i_flags) +static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, + loff_t size, unsigned long flags, unsigned int i_flags) { struct inode *inode; struct file *res; @@ -4794,7 +4781,6 @@ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, l inode = shmem_get_inode(&nop_mnt_idmap, mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); - if (IS_ERR(inode)) { shmem_unacct_size(flags, size); return ERR_CAST(inode); -- cgit v1.2.3 From 4199f51a7eb2054d68964efbd8d39c68053a8714 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Fri, 29 Sep 2023 20:30:03 -0700 Subject: shmem: shmem_acct_blocks() and shmem_inode_acct_blocks() By historical accident, shmem_acct_block() and shmem_inode_acct_block() were never pluralized when the pages argument was added, despite their complements being shmem_unacct_blocks() and shmem_inode_unacct_blocks() all along. It has been an irritation: fix their naming at last. Link: https://lkml.kernel.org/r/9124094-e4ab-8be7-ef80-9a87bdc2e4fc@google.com Signed-off-by: Hugh Dickins Reviewed-by: Jan Kara Cc: Axel Rasmussen Cc: Carlos Maiolino Cc: Christian Brauner Cc: Chuck Lever Cc: Darrick J. Wong Cc: Dave Chinner Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Tim Chen Signed-off-by: Andrew Morton --- mm/shmem.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'mm/shmem.c') diff --git a/mm/shmem.c b/mm/shmem.c index 3540fc598848..fabce18ed9e5 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -189,10 +189,10 @@ static inline int shmem_reacct_size(unsigned long flags, /* * ... whereas tmpfs objects are accounted incrementally as * pages are allocated, in order to allow large sparse files. - * shmem_get_folio reports shmem_acct_block failure as -ENOSPC not -ENOMEM, + * shmem_get_folio reports shmem_acct_blocks failure as -ENOSPC not -ENOMEM, * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. */ -static inline int shmem_acct_block(unsigned long flags, long pages) +static inline int shmem_acct_blocks(unsigned long flags, long pages) { if (!(flags & VM_NORESERVE)) return 0; @@ -207,13 +207,13 @@ static inline void shmem_unacct_blocks(unsigned long flags, long pages) vm_unacct_memory(pages * VM_ACCT(PAGE_SIZE)); } -static int shmem_inode_acct_block(struct inode *inode, long pages) +static int shmem_inode_acct_blocks(struct inode *inode, long pages) { struct shmem_inode_info *info = SHMEM_I(inode); struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); int err = -ENOSPC; - if (shmem_acct_block(info->flags, pages)) + if (shmem_acct_blocks(info->flags, pages)) return err; might_sleep(); /* when quotas */ @@ -447,7 +447,7 @@ bool shmem_charge(struct inode *inode, long pages) { struct address_space *mapping = inode->i_mapping; - if (shmem_inode_acct_block(inode, pages)) + if (shmem_inode_acct_blocks(inode, pages)) return false; /* nrpages adjustment first, then shmem_recalc_inode() when balanced */ @@ -1671,7 +1671,7 @@ static struct folio *shmem_alloc_and_acct_folio(gfp_t gfp, struct inode *inode, huge = false; nr = huge ? HPAGE_PMD_NR : 1; - err = shmem_inode_acct_block(inode, nr); + err = shmem_inode_acct_blocks(inode, nr); if (err) goto failed; @@ -2572,7 +2572,7 @@ int shmem_mfill_atomic_pte(pmd_t *dst_pmd, int ret; pgoff_t max_off; - if (shmem_inode_acct_block(inode, 1)) { + if (shmem_inode_acct_blocks(inode, 1)) { /* * We may have got a page, returned -ENOENT triggering a retry, * and now we find ourselves with -ENOMEM. Release the page, to -- cgit v1.2.3 From 054a9f7ccd0a60607fb9bbe1e06ca671494971bf Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Fri, 29 Sep 2023 20:31:27 -0700 Subject: shmem: move memcg charge out of shmem_add_to_page_cache() Extract shmem's memcg charging out of shmem_add_to_page_cache(): it's misleading done there, because many calls are dealing with a swapcache page, whose memcg is nowadays always remembered while swapped out, then the charge re-levied when it's brought back into swapcache. Temporarily move it back up to the shmem_get_folio_gfp() level, where the memcg was charged before v5.8; but the next commit goes on to move it back down to a new home. In making this change, it becomes clear that shmem_swapin_folio() does not need to know the vma, just the fault mm (if any): call it fault_mm rather than charge_mm - let mem_cgroup_charge() decide whom to charge. Link: https://lkml.kernel.org/r/4b2143c5-bf32-64f0-841-81a81158dac@google.com Signed-off-by: Hugh Dickins Reviewed-by: Jan Kara Cc: Axel Rasmussen Cc: Carlos Maiolino Cc: Christian Brauner Cc: Chuck Lever Cc: Darrick J. Wong Cc: Dave Chinner Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Tim Chen Signed-off-by: Andrew Morton --- mm/shmem.c | 68 +++++++++++++++++++++++++++----------------------------------- 1 file changed, 29 insertions(+), 39 deletions(-) (limited to 'mm/shmem.c') diff --git a/mm/shmem.c b/mm/shmem.c index fabce18ed9e5..670f77de3238 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -146,9 +146,8 @@ static unsigned long shmem_default_max_inodes(void) #endif static int shmem_swapin_folio(struct inode *inode, pgoff_t index, - struct folio **foliop, enum sgp_type sgp, - gfp_t gfp, struct vm_area_struct *vma, - vm_fault_t *fault_type); + struct folio **foliop, enum sgp_type sgp, gfp_t gfp, + struct mm_struct *fault_mm, vm_fault_t *fault_type); static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) { @@ -760,12 +759,10 @@ static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo, */ static int shmem_add_to_page_cache(struct folio *folio, struct address_space *mapping, - pgoff_t index, void *expected, gfp_t gfp, - struct mm_struct *charge_mm) + pgoff_t index, void *expected, gfp_t gfp) { XA_STATE_ORDER(xas, &mapping->i_pages, index, folio_order(folio)); long nr = folio_nr_pages(folio); - int error; VM_BUG_ON_FOLIO(index != round_down(index, nr), folio); VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); @@ -776,16 +773,7 @@ static int shmem_add_to_page_cache(struct folio *folio, folio->mapping = mapping; folio->index = index; - if (!folio_test_swapcache(folio)) { - error = mem_cgroup_charge(folio, charge_mm, gfp); - if (error) { - if (folio_test_pmd_mappable(folio)) { - count_vm_event(THP_FILE_FALLBACK); - count_vm_event(THP_FILE_FALLBACK_CHARGE); - } - goto error; - } - } + gfp &= GFP_RECLAIM_MASK; folio_throttle_swaprate(folio, gfp); do { @@ -813,15 +801,12 @@ unlock: } while (xas_nomem(&xas, gfp)); if (xas_error(&xas)) { - error = xas_error(&xas); - goto error; + folio->mapping = NULL; + folio_ref_sub(folio, nr); + return xas_error(&xas); } return 0; -error: - folio->mapping = NULL; - folio_ref_sub(folio, nr); - return error; } /* @@ -1324,10 +1309,8 @@ static int shmem_unuse_swap_entries(struct inode *inode, if (!xa_is_value(folio)) continue; - error = shmem_swapin_folio(inode, indices[i], - &folio, SGP_CACHE, - mapping_gfp_mask(mapping), - NULL, NULL); + error = shmem_swapin_folio(inode, indices[i], &folio, SGP_CACHE, + mapping_gfp_mask(mapping), NULL, NULL); if (error == 0) { folio_unlock(folio); folio_put(folio); @@ -1810,12 +1793,11 @@ static void shmem_set_folio_swapin_error(struct inode *inode, pgoff_t index, */ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, struct folio **foliop, enum sgp_type sgp, - gfp_t gfp, struct vm_area_struct *vma, + gfp_t gfp, struct mm_struct *fault_mm, vm_fault_t *fault_type) { struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); - struct mm_struct *charge_mm = vma ? vma->vm_mm : NULL; struct swap_info_struct *si; struct folio *folio = NULL; swp_entry_t swap; @@ -1843,7 +1825,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, if (fault_type) { *fault_type |= VM_FAULT_MAJOR; count_vm_event(PGMAJFAULT); - count_memcg_event_mm(charge_mm, PGMAJFAULT); + count_memcg_event_mm(fault_mm, PGMAJFAULT); } /* Here we actually start the io */ folio = shmem_swapin(swap, gfp, info, index); @@ -1880,8 +1862,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, } error = shmem_add_to_page_cache(folio, mapping, index, - swp_to_radix_entry(swap), gfp, - charge_mm); + swp_to_radix_entry(swap), gfp); if (error) goto failed; @@ -1929,7 +1910,7 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); struct shmem_sb_info *sbinfo; - struct mm_struct *charge_mm; + struct mm_struct *fault_mm; struct folio *folio; pgoff_t hindex; gfp_t huge_gfp; @@ -1946,7 +1927,7 @@ repeat: } sbinfo = SHMEM_SB(inode->i_sb); - charge_mm = vma ? vma->vm_mm : NULL; + fault_mm = vma ? vma->vm_mm : NULL; folio = filemap_get_entry(mapping, index); if (folio && vma && userfaultfd_minor(vma)) { @@ -1958,7 +1939,7 @@ repeat: if (xa_is_value(folio)) { error = shmem_swapin_folio(inode, index, &folio, - sgp, gfp, vma, fault_type); + sgp, gfp, fault_mm, fault_type); if (error == -EEXIST) goto repeat; @@ -2044,9 +2025,16 @@ alloc_nohuge: if (sgp == SGP_WRITE) __folio_set_referenced(folio); - error = shmem_add_to_page_cache(folio, mapping, hindex, - NULL, gfp & GFP_RECLAIM_MASK, - charge_mm); + error = mem_cgroup_charge(folio, fault_mm, gfp); + if (error) { + if (folio_test_pmd_mappable(folio)) { + count_vm_event(THP_FILE_FALLBACK); + count_vm_event(THP_FILE_FALLBACK_CHARGE); + } + goto unacct; + } + + error = shmem_add_to_page_cache(folio, mapping, hindex, NULL, gfp); if (error) goto unacct; @@ -2644,8 +2632,10 @@ int shmem_mfill_atomic_pte(pmd_t *dst_pmd, if (unlikely(pgoff >= max_off)) goto out_release; - ret = shmem_add_to_page_cache(folio, mapping, pgoff, NULL, - gfp & GFP_RECLAIM_MASK, dst_vma->vm_mm); + ret = mem_cgroup_charge(folio, dst_vma->vm_mm, gfp); + if (ret) + goto out_release; + ret = shmem_add_to_page_cache(folio, mapping, pgoff, NULL, gfp); if (ret) goto out_release; -- cgit v1.2.3 From 3022fd7af9604d44ec43da8a4398872989599b18 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Fri, 29 Sep 2023 20:32:40 -0700 Subject: shmem: _add_to_page_cache() before shmem_inode_acct_blocks() There has been a recurring problem, that when a tmpfs volume is being filled by racing threads, some fail with ENOSPC (or consequent SIGBUS or EFAULT) even though all allocations were within the permitted size. This was a problem since early days, but magnified and complicated by the addition of huge pages. We have often worked around it by adding some slop to the tmpfs size, but it's hard to say how much is needed, and some users prefer not to do that e.g. keeping sparse files in a tightly tailored tmpfs helps to prevent accidental writing to holes. This comes from the allocation sequence: 1. check page cache for existing folio 2. check and reserve from vm_enough_memory 3. check and account from size of tmpfs 4. if huge, check page cache for overlapping folio 5. allocate physical folio, huge or small 6. check and charge from mem cgroup limit 7. add to page cache (but maybe another folio already got in). Concurrent tasks allocating at the same position could deplete the size allowance and fail. Doing vm_enough_memory and size checks before the folio allocation was intentional (to limit the load on the page allocator from this source) and still has some virtue; but memory cgroup never did that, so I think it's better reordered to favour predictable behaviour. 1. check page cache for existing folio 2. if huge, check page cache for overlapping folio 3. allocate physical folio, huge or small 4. check and charge from mem cgroup limit 5. add to page cache (but maybe another folio already got in) 6. check and reserve from vm_enough_memory 7. check and account from size of tmpfs. The folio lock held from allocation onwards ensures that the !uptodate folio cannot be used by others, and can safely be deleted from the cache if checks 6 or 7 subsequently fail (and those waiting on folio lock already check that the folio was not truncated once they get the lock); and the early addition to page cache ensures that racers find it before they try to duplicate the accounting. Seize the opportunity to tidy up shmem_get_folio_gfp()'s ENOSPC retrying, which can be combined inside the new shmem_alloc_and_add_folio(): doing 2 splits twice (once huge, once nonhuge) is not exactly equivalent to trying 5 splits (and giving up early on huge), but let's keep it simple unless more complication proves necessary. Userfaultfd is a foreign country: they do things differently there, and for good reason - to avoid mmap_lock deadlock. Leave ordering in shmem_mfill_atomic_pte() untouched for now, but I would rather like to mesh it better with shmem_get_folio_gfp() in the future. Link: https://lkml.kernel.org/r/22ddd06-d919-33b-1219-56335c1bf28e@google.com Signed-off-by: Hugh Dickins Cc: Axel Rasmussen Cc: Carlos Maiolino Cc: Christian Brauner Cc: Chuck Lever Cc: Darrick J. Wong Cc: Dave Chinner Cc: Jan Kara Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Tim Chen Signed-off-by: Andrew Morton --- mm/shmem.c | 229 +++++++++++++++++++++++++++++++------------------------------ 1 file changed, 118 insertions(+), 111 deletions(-) (limited to 'mm/shmem.c') diff --git a/mm/shmem.c b/mm/shmem.c index 670f77de3238..269cd3c1110f 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -789,13 +789,11 @@ static int shmem_add_to_page_cache(struct folio *folio, xas_store(&xas, folio); if (xas_error(&xas)) goto unlock; - if (folio_test_pmd_mappable(folio)) { - count_vm_event(THP_FILE_ALLOC); + if (folio_test_pmd_mappable(folio)) __lruvec_stat_mod_folio(folio, NR_SHMEM_THPS, nr); - } - mapping->nrpages += nr; __lruvec_stat_mod_folio(folio, NR_FILE_PAGES, nr); __lruvec_stat_mod_folio(folio, NR_SHMEM, nr); + mapping->nrpages += nr; unlock: xas_unlock_irq(&xas); } while (xas_nomem(&xas, gfp)); @@ -1612,25 +1610,17 @@ static struct folio *shmem_alloc_hugefolio(gfp_t gfp, struct shmem_inode_info *info, pgoff_t index) { struct vm_area_struct pvma; - struct address_space *mapping = info->vfs_inode.i_mapping; - pgoff_t hindex; struct folio *folio; - hindex = round_down(index, HPAGE_PMD_NR); - if (xa_find(&mapping->i_pages, &hindex, hindex + HPAGE_PMD_NR - 1, - XA_PRESENT)) - return NULL; - - shmem_pseudo_vma_init(&pvma, info, hindex); + shmem_pseudo_vma_init(&pvma, info, index); folio = vma_alloc_folio(gfp, HPAGE_PMD_ORDER, &pvma, 0, true); shmem_pseudo_vma_destroy(&pvma); - if (!folio) - count_vm_event(THP_FILE_FALLBACK); + return folio; } static struct folio *shmem_alloc_folio(gfp_t gfp, - struct shmem_inode_info *info, pgoff_t index) + struct shmem_inode_info *info, pgoff_t index) { struct vm_area_struct pvma; struct folio *folio; @@ -1642,36 +1632,101 @@ static struct folio *shmem_alloc_folio(gfp_t gfp, return folio; } -static struct folio *shmem_alloc_and_acct_folio(gfp_t gfp, struct inode *inode, - pgoff_t index, bool huge) +static struct folio *shmem_alloc_and_add_folio(gfp_t gfp, + struct inode *inode, pgoff_t index, + struct mm_struct *fault_mm, bool huge) { + struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); struct folio *folio; - int nr; - int err; + long pages; + int error; if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) huge = false; - nr = huge ? HPAGE_PMD_NR : 1; - err = shmem_inode_acct_blocks(inode, nr); - if (err) - goto failed; + if (huge) { + pages = HPAGE_PMD_NR; + index = round_down(index, HPAGE_PMD_NR); + + /* + * Check for conflict before waiting on a huge allocation. + * Conflict might be that a huge page has just been allocated + * and added to page cache by a racing thread, or that there + * is already at least one small page in the huge extent. + * Be careful to retry when appropriate, but not forever! + * Elsewhere -EEXIST would be the right code, but not here. + */ + if (xa_find(&mapping->i_pages, &index, + index + HPAGE_PMD_NR - 1, XA_PRESENT)) + return ERR_PTR(-E2BIG); - if (huge) folio = shmem_alloc_hugefolio(gfp, info, index); - else + if (!folio) + count_vm_event(THP_FILE_FALLBACK); + } else { + pages = 1; folio = shmem_alloc_folio(gfp, info, index); - if (folio) { - __folio_set_locked(folio); - __folio_set_swapbacked(folio); - return folio; + } + if (!folio) + return ERR_PTR(-ENOMEM); + + __folio_set_locked(folio); + __folio_set_swapbacked(folio); + + gfp &= GFP_RECLAIM_MASK; + error = mem_cgroup_charge(folio, fault_mm, gfp); + if (error) { + if (xa_find(&mapping->i_pages, &index, + index + pages - 1, XA_PRESENT)) { + error = -EEXIST; + } else if (huge) { + count_vm_event(THP_FILE_FALLBACK); + count_vm_event(THP_FILE_FALLBACK_CHARGE); + } + goto unlock; } - err = -ENOMEM; - shmem_inode_unacct_blocks(inode, nr); -failed: - return ERR_PTR(err); + error = shmem_add_to_page_cache(folio, mapping, index, NULL, gfp); + if (error) + goto unlock; + + error = shmem_inode_acct_blocks(inode, pages); + if (error) { + struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); + long freed; + /* + * Try to reclaim some space by splitting a few + * large folios beyond i_size on the filesystem. + */ + shmem_unused_huge_shrink(sbinfo, NULL, 2); + /* + * And do a shmem_recalc_inode() to account for freed pages: + * except our folio is there in cache, so not quite balanced. + */ + spin_lock(&info->lock); + freed = pages + info->alloced - info->swapped - + READ_ONCE(mapping->nrpages); + if (freed > 0) + info->alloced -= freed; + spin_unlock(&info->lock); + if (freed > 0) + shmem_inode_unacct_blocks(inode, freed); + error = shmem_inode_acct_blocks(inode, pages); + if (error) { + filemap_remove_folio(folio); + goto unlock; + } + } + + shmem_recalc_inode(inode, pages, 0); + folio_add_lru(folio); + return folio; + +unlock: + folio_unlock(folio); + folio_put(folio); + return ERR_PTR(error); } /* @@ -1907,29 +1962,22 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, struct vm_fault *vmf, vm_fault_t *fault_type) { struct vm_area_struct *vma = vmf ? vmf->vma : NULL; - struct address_space *mapping = inode->i_mapping; - struct shmem_inode_info *info = SHMEM_I(inode); - struct shmem_sb_info *sbinfo; struct mm_struct *fault_mm; struct folio *folio; - pgoff_t hindex; - gfp_t huge_gfp; int error; - int once = 0; - int alloced = 0; + bool alloced; if (index > (MAX_LFS_FILESIZE >> PAGE_SHIFT)) return -EFBIG; repeat: if (sgp <= SGP_CACHE && - ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) { + ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) return -EINVAL; - } - sbinfo = SHMEM_SB(inode->i_sb); + alloced = false; fault_mm = vma ? vma->vm_mm : NULL; - folio = filemap_get_entry(mapping, index); + folio = filemap_get_entry(inode->i_mapping, index); if (folio && vma && userfaultfd_minor(vma)) { if (!xa_is_value(folio)) folio_put(folio); @@ -1951,7 +1999,7 @@ repeat: folio_lock(folio); /* Has the folio been truncated or swapped out? */ - if (unlikely(folio->mapping != mapping)) { + if (unlikely(folio->mapping != inode->i_mapping)) { folio_unlock(folio); folio_put(folio); goto repeat; @@ -1986,65 +2034,38 @@ repeat: return 0; } - if (!shmem_is_huge(inode, index, false, - vma ? vma->vm_mm : NULL, vma ? vma->vm_flags : 0)) - goto alloc_nohuge; + if (shmem_is_huge(inode, index, false, fault_mm, + vma ? vma->vm_flags : 0)) { + gfp_t huge_gfp; - huge_gfp = vma_thp_gfp_mask(vma); - huge_gfp = limit_gfp_mask(huge_gfp, gfp); - folio = shmem_alloc_and_acct_folio(huge_gfp, inode, index, true); - if (IS_ERR(folio)) { -alloc_nohuge: - folio = shmem_alloc_and_acct_folio(gfp, inode, index, false); + huge_gfp = vma_thp_gfp_mask(vma); + huge_gfp = limit_gfp_mask(huge_gfp, gfp); + folio = shmem_alloc_and_add_folio(huge_gfp, + inode, index, fault_mm, true); + if (!IS_ERR(folio)) { + count_vm_event(THP_FILE_ALLOC); + goto alloced; + } + if (PTR_ERR(folio) == -EEXIST) + goto repeat; } - if (IS_ERR(folio)) { - int retry = 5; + folio = shmem_alloc_and_add_folio(gfp, inode, index, fault_mm, false); + if (IS_ERR(folio)) { error = PTR_ERR(folio); + if (error == -EEXIST) + goto repeat; folio = NULL; - if (error != -ENOSPC) - goto unlock; - /* - * Try to reclaim some space by splitting a large folio - * beyond i_size on the filesystem. - */ - while (retry--) { - int ret; - - ret = shmem_unused_huge_shrink(sbinfo, NULL, 1); - if (ret == SHRINK_STOP) - break; - if (ret) - goto alloc_nohuge; - } goto unlock; } - hindex = round_down(index, folio_nr_pages(folio)); - - if (sgp == SGP_WRITE) - __folio_set_referenced(folio); - - error = mem_cgroup_charge(folio, fault_mm, gfp); - if (error) { - if (folio_test_pmd_mappable(folio)) { - count_vm_event(THP_FILE_FALLBACK); - count_vm_event(THP_FILE_FALLBACK_CHARGE); - } - goto unacct; - } - - error = shmem_add_to_page_cache(folio, mapping, hindex, NULL, gfp); - if (error) - goto unacct; - - folio_add_lru(folio); - shmem_recalc_inode(inode, folio_nr_pages(folio), 0); +alloced: alloced = true; - if (folio_test_pmd_mappable(folio) && DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) < folio_next_index(folio) - 1) { + struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); + struct shmem_inode_info *info = SHMEM_I(inode); /* * Part of the large folio is beyond i_size: subject * to shrink under memory pressure. @@ -2062,6 +2083,8 @@ alloc_nohuge: spin_unlock(&sbinfo->shrinklist_lock); } + if (sgp == SGP_WRITE) + folio_set_referenced(folio); /* * Let SGP_FALLOC use the SGP_WRITE optimization on a new folio. */ @@ -2085,11 +2108,6 @@ clear: /* Perhaps the file has been truncated since we checked */ if (sgp <= SGP_CACHE && ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) { - if (alloced) { - folio_clear_dirty(folio); - filemap_remove_folio(folio); - shmem_recalc_inode(inode, 0, 0); - } error = -EINVAL; goto unlock; } @@ -2100,25 +2118,14 @@ out: /* * Error recovery. */ -unacct: - shmem_inode_unacct_blocks(inode, folio_nr_pages(folio)); - - if (folio_test_large(folio)) { - folio_unlock(folio); - folio_put(folio); - goto alloc_nohuge; - } unlock: + if (alloced) + filemap_remove_folio(folio); + shmem_recalc_inode(inode, 0, 0); if (folio) { folio_unlock(folio); folio_put(folio); } - if (error == -ENOSPC && !once++) { - shmem_recalc_inode(inode, 0, 0); - goto repeat; - } - if (error == -EEXIST) - goto repeat; return error; } -- cgit v1.2.3 From beb9868628445306958fd7b2da1cd369a4a381cc Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Fri, 29 Sep 2023 20:42:45 -0700 Subject: shmem,percpu_counter: add _limited_add(fbc, limit, amount) Percpu counter's compare and add are separate functions: without locking around them (which would defeat their purpose), it has been possible to overflow the intended limit. Imagine all the other CPUs fallocating tmpfs huge pages to the limit, in between this CPU's compare and its add. I have not seen reports of that happening; but tmpfs's recent addition of dquot_alloc_block_nodirty() in between the compare and the add makes it even more likely, and I'd be uncomfortable to leave it unfixed. Introduce percpu_counter_limited_add(fbc, limit, amount) to prevent it. I believe this implementation is correct, and slightly more efficient than the combination of compare and add (taking the lock once rather than twice when nearing full - the last 128MiB of a tmpfs volume on a machine with 128 CPUs and 4KiB pages); but it does beg for a better design - when nearing full, there is no new batching, but the costly percpu counter sum across CPUs still has to be done, while locked. Follow __percpu_counter_sum()'s example, including cpu_dying_mask as well as cpu_online_mask: but shouldn't __percpu_counter_compare() and __percpu_counter_limited_add() then be adding a num_dying_cpus() to num_online_cpus(), when they calculate the maximum which could be held across CPUs? But the times when it matters would be vanishingly rare. Link: https://lkml.kernel.org/r/bb817848-2d19-bcc8-39ca-ea179af0f0b4@google.com Signed-off-by: Hugh Dickins Reviewed-by: Jan Kara Cc: Tim Chen Cc: Dave Chinner Cc: Darrick J. Wong Cc: Axel Rasmussen Cc: Carlos Maiolino Cc: Christian Brauner Cc: Chuck Lever Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton --- mm/shmem.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'mm/shmem.c') diff --git a/mm/shmem.c b/mm/shmem.c index 269cd3c1110f..61b170324e5c 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -217,15 +217,15 @@ static int shmem_inode_acct_blocks(struct inode *inode, long pages) might_sleep(); /* when quotas */ if (sbinfo->max_blocks) { - if (percpu_counter_compare(&sbinfo->used_blocks, - sbinfo->max_blocks - pages) > 0) + if (!percpu_counter_limited_add(&sbinfo->used_blocks, + sbinfo->max_blocks, pages)) goto unacct; err = dquot_alloc_block_nodirty(inode, pages); - if (err) + if (err) { + percpu_counter_sub(&sbinfo->used_blocks, pages); goto unacct; - - percpu_counter_add(&sbinfo->used_blocks, pages); + } } else { err = dquot_alloc_block_nodirty(inode, pages); if (err) -- cgit v1.2.3 From 28464bbb2ddc199433383994bcb9600c8034afa1 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Thu, 12 Oct 2023 18:04:29 +0100 Subject: mm: update memfd seal write check to include F_SEAL_WRITE The seal_check_future_write() function is called by shmem_mmap() or hugetlbfs_file_mmap() to disallow any future writable mappings of an memfd sealed this way. The F_SEAL_WRITE flag is not checked here, as that is handled via the mapping->i_mmap_writable mechanism and so any attempt at a mapping would fail before this could be run. However we intend to change this, meaning this check can be performed for F_SEAL_WRITE mappings also. The logic here is equally applicable to both flags, so update this function to accommodate both and rename it accordingly. Link: https://lkml.kernel.org/r/913628168ce6cce77df7d13a63970bae06a526e0.1697116581.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes Reviewed-by: Jan Kara Cc: Alexander Viro Cc: Andy Lutomirski Cc: Christian Brauner Cc: Hugh Dickins Cc: Matthew Wilcox (Oracle) Cc: Mike Kravetz Cc: Muchun Song Signed-off-by: Andrew Morton --- mm/shmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/shmem.c') diff --git a/mm/shmem.c b/mm/shmem.c index 61b170324e5c..bcbe9dbb9f5f 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2378,7 +2378,7 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma) struct shmem_inode_info *info = SHMEM_I(inode); int ret; - ret = seal_check_future_write(info->seals, vma); + ret = seal_check_write(info->seals, vma); if (ret) return ret; -- cgit v1.2.3 From ddc1a5cbc05dc62743a2f409b96faa5cf95ba064 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Thu, 19 Oct 2023 13:39:08 -0700 Subject: mempolicy: alloc_pages_mpol() for NUMA policy without vma Shrink shmem's stack usage by eliminating the pseudo-vma from its folio allocation. alloc_pages_mpol(gfp, order, pol, ilx, nid) becomes the principal actor for passing mempolicy choice down to __alloc_pages(), rather than vma_alloc_folio(gfp, order, vma, addr, hugepage). vma_alloc_folio() and alloc_pages() remain, but as wrappers around alloc_pages_mpol(). alloc_pages_bulk_*() untouched, except to provide the additional args to policy_nodemask(), which subsumes policy_node(). Cleanup throughout, cutting out some unhelpful "helpers". It would all be much simpler without MPOL_INTERLEAVE, but that adds a dynamic to the constant mpol: complicated by v3.6 commit 09c231cb8bfd ("tmpfs: distribute interleave better across nodes"), which added ino bias to the interleave, hidden from mm/mempolicy.c until this commit. Hence "ilx" throughout, the "interleave index". Originally I thought it could be done just with nid, but that's wrong: the nodemask may come from the shared policy layer below a shmem vma, or it may come from the task layer above a shmem vma; and without the final nodemask then nodeid cannot be decided. And how ilx is applied depends also on page order. The interleave index is almost always irrelevant unless MPOL_INTERLEAVE: with one exception in alloc_pages_mpol(), where the NO_INTERLEAVE_INDEX passed down from vma-less alloc_pages() is also used as hint not to use THP-style hugepage allocation - to avoid the overhead of a hugepage arg (though I don't understand why we never just added a GFP bit for THP - if it actually needs a different allocation strategy from other pages of the same order). vma_alloc_folio() still carries its hugepage arg here, but it is not used, and should be removed when agreed. get_vma_policy() no longer allows a NULL vma: over time I believe we've eradicated all the places which used to need it e.g. swapoff and madvise used to pass NULL vma to read_swap_cache_async(), but now know the vma. [hughd@google.com: handle NULL mpol being passed to __read_swap_cache_async()] Link: https://lkml.kernel.org/r/ea419956-4751-0102-21f7-9c93cb957892@google.com Link: https://lkml.kernel.org/r/74e34633-6060-f5e3-aee-7040d43f2e93@google.com Link: https://lkml.kernel.org/r/1738368e-bac0-fd11-ed7f-b87142a939fe@google.com Signed-off-by: Hugh Dickins Cc: Andi Kleen Cc: Christoph Lameter Cc: David Hildenbrand Cc: Greg Kroah-Hartman Cc: Huang Ying Cc: Kefeng Wang Cc: Matthew Wilcox (Oracle) Cc: Mel Gorman Cc: Michal Hocko Cc: Mike Kravetz Cc: Nhat Pham Cc: Sidhartha Kumar Cc: Suren Baghdasaryan Cc: Tejun heo Cc: Vishal Moola (Oracle) Cc: Yang Shi Cc: Yosry Ahmed Cc: Domenico Cerasuolo Cc: Johannes Weiner Signed-off-by: Andrew Morton --- mm/shmem.c | 92 ++++++++++++++++++++++++++++++++++---------------------------- 1 file changed, 51 insertions(+), 41 deletions(-) (limited to 'mm/shmem.c') diff --git a/mm/shmem.c b/mm/shmem.c index bcbe9dbb9f5f..a314a25aea8c 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1544,38 +1544,20 @@ static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) return NULL; } #endif /* CONFIG_NUMA && CONFIG_TMPFS */ -#ifndef CONFIG_NUMA -#define vm_policy vm_private_data -#endif - -static void shmem_pseudo_vma_init(struct vm_area_struct *vma, - struct shmem_inode_info *info, pgoff_t index) -{ - /* Create a pseudo vma that just contains the policy */ - vma_init(vma, NULL); - /* Bias interleave by inode number to distribute better across nodes */ - vma->vm_pgoff = index + info->vfs_inode.i_ino; - vma->vm_policy = mpol_shared_policy_lookup(&info->policy, index); -} -static void shmem_pseudo_vma_destroy(struct vm_area_struct *vma) -{ - /* Drop reference taken by mpol_shared_policy_lookup() */ - mpol_cond_put(vma->vm_policy); -} +static struct mempolicy *shmem_get_pgoff_policy(struct shmem_inode_info *info, + pgoff_t index, unsigned int order, pgoff_t *ilx); -static struct folio *shmem_swapin(swp_entry_t swap, gfp_t gfp, +static struct folio *shmem_swapin_cluster(swp_entry_t swap, gfp_t gfp, struct shmem_inode_info *info, pgoff_t index) { - struct vm_area_struct pvma; + struct mempolicy *mpol; + pgoff_t ilx; struct page *page; - struct vm_fault vmf = { - .vma = &pvma, - }; - shmem_pseudo_vma_init(&pvma, info, index); - page = swap_cluster_readahead(swap, gfp, &vmf); - shmem_pseudo_vma_destroy(&pvma); + mpol = shmem_get_pgoff_policy(info, index, 0, &ilx); + page = swap_cluster_readahead(swap, gfp, mpol, ilx); + mpol_cond_put(mpol); if (!page) return NULL; @@ -1609,27 +1591,29 @@ static gfp_t limit_gfp_mask(gfp_t huge_gfp, gfp_t limit_gfp) static struct folio *shmem_alloc_hugefolio(gfp_t gfp, struct shmem_inode_info *info, pgoff_t index) { - struct vm_area_struct pvma; - struct folio *folio; + struct mempolicy *mpol; + pgoff_t ilx; + struct page *page; - shmem_pseudo_vma_init(&pvma, info, index); - folio = vma_alloc_folio(gfp, HPAGE_PMD_ORDER, &pvma, 0, true); - shmem_pseudo_vma_destroy(&pvma); + mpol = shmem_get_pgoff_policy(info, index, HPAGE_PMD_ORDER, &ilx); + page = alloc_pages_mpol(gfp, HPAGE_PMD_ORDER, mpol, ilx, numa_node_id()); + mpol_cond_put(mpol); - return folio; + return page_rmappable_folio(page); } static struct folio *shmem_alloc_folio(gfp_t gfp, struct shmem_inode_info *info, pgoff_t index) { - struct vm_area_struct pvma; - struct folio *folio; + struct mempolicy *mpol; + pgoff_t ilx; + struct page *page; - shmem_pseudo_vma_init(&pvma, info, index); - folio = vma_alloc_folio(gfp, 0, &pvma, 0, false); - shmem_pseudo_vma_destroy(&pvma); + mpol = shmem_get_pgoff_policy(info, index, 0, &ilx); + page = alloc_pages_mpol(gfp, 0, mpol, ilx, numa_node_id()); + mpol_cond_put(mpol); - return folio; + return (struct folio *)page; } static struct folio *shmem_alloc_and_add_folio(gfp_t gfp, @@ -1883,7 +1867,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, count_memcg_event_mm(fault_mm, PGMAJFAULT); } /* Here we actually start the io */ - folio = shmem_swapin(swap, gfp, info, index); + folio = shmem_swapin_cluster(swap, gfp, info, index); if (!folio) { error = -ENOMEM; goto failed; @@ -2334,15 +2318,41 @@ static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol) } static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, - unsigned long addr) + unsigned long addr, pgoff_t *ilx) { struct inode *inode = file_inode(vma->vm_file); pgoff_t index; + /* + * Bias interleave by inode number to distribute better across nodes; + * but this interface is independent of which page order is used, so + * supplies only that bias, letting caller apply the offset (adjusted + * by page order, as in shmem_get_pgoff_policy() and get_vma_policy()). + */ + *ilx = inode->i_ino; index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index); } -#endif + +static struct mempolicy *shmem_get_pgoff_policy(struct shmem_inode_info *info, + pgoff_t index, unsigned int order, pgoff_t *ilx) +{ + struct mempolicy *mpol; + + /* Bias interleave by inode number to distribute better across nodes */ + *ilx = info->vfs_inode.i_ino + (index >> order); + + mpol = mpol_shared_policy_lookup(&info->policy, index); + return mpol ? mpol : get_task_policy(current); +} +#else +static struct mempolicy *shmem_get_pgoff_policy(struct shmem_inode_info *info, + pgoff_t index, unsigned int order, pgoff_t *ilx) +{ + *ilx = 0; + return NULL; +} +#endif /* CONFIG_NUMA */ int shmem_lock(struct file *file, int lock, struct ucounts *ucounts) { -- cgit v1.2.3