Any updates? Thank you, Kyungmin Park
On Wed, Feb 11, 2015 at 11:50 PM, Krzysztof Kozlowski <k.kozlow...@samsung.com> wrote: > Allow notifying user space when used space of tmpfs exceeds specified > level. > > The utilization level is passed as mount option 'warn_used'. The kernel > will notify user-space through eventfd after exceeding this number of > used blocks. > > The eventfd descriptor has to be passed through sysfs file: > /sys/fs/tmpfs/tmpfs-[0-9]+/warn_used_blocks_efd > > Signed-off-by: Krzysztof Kozlowski <k.kozlow...@samsung.com> > --- > include/linux/shmem_fs.h | 4 ++ > mm/shmem.c | 138 > ++++++++++++++++++++++++++++++++++++++++++++++- > 2 files changed, 140 insertions(+), 2 deletions(-) > > diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h > index 50777b5b1e4c..c2ec9909da95 100644 > --- a/include/linux/shmem_fs.h > +++ b/include/linux/shmem_fs.h > @@ -35,6 +35,10 @@ struct shmem_sb_info { > kgid_t gid; /* Mount gid for root directory */ > umode_t mode; /* Mount mode for root directory */ > struct mempolicy *mpol; /* default memory policy for mappings */ > + unsigned long warn_used; /* Warn on reaching used blocks */ > + struct kobject s_kobj; /* kobj for sysfs attributes */ > + struct completion s_kobj_unregister; /* synchronization for put_super > */ > + struct eventfd_ctx *warn_used_efd; /* user-space passed eventfd */ > }; > > static inline struct shmem_inode_info *SHMEM_I(struct inode *inode) > diff --git a/mm/shmem.c b/mm/shmem.c > index f69d296bd0a3..b559adcef3b3 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -34,6 +34,7 @@ > #include <linux/aio.h> > > static struct vfsmount *shm_mnt; > +static struct kset *shmem_kset; > > #ifdef CONFIG_SHMEM > /* > @@ -69,6 +70,7 @@ static struct vfsmount *shm_mnt; > #include <linux/syscalls.h> > #include <linux/fcntl.h> > #include <uapi/linux/memfd.h> > +#include <linux/eventfd.h> > > #include <asm/uaccess.h> > #include <asm/pgtable.h> > @@ -199,6 +201,106 @@ static struct backing_dev_info shmem_backing_dev_info > __read_mostly = { > static LIST_HEAD(shmem_swaplist); > static DEFINE_MUTEX(shmem_swaplist_mutex); > > + > +struct shmem_attr { > + struct attribute attr; > + ssize_t (*show)(struct shmem_attr *, struct shmem_sb_info *, char *); > + ssize_t (*store)(struct shmem_attr *, struct shmem_sb_info *, > + const char *, size_t); > +}; > + > +static int shmem_setup_warn_used_blocks_eventfd(struct shmem_sb_info *sbinfo, > + unsigned int efd) > +{ > + int ret = 0; > + > + if (sbinfo->warn_used_efd) { > + eventfd_ctx_put(sbinfo->warn_used_efd); > + sbinfo->warn_used_efd = NULL; > + } > + > + sbinfo->warn_used_efd = eventfd_ctx_fdget(efd); > + if (IS_ERR(sbinfo->warn_used_efd)) { > + ret = PTR_ERR(sbinfo->warn_used_efd); > + sbinfo->warn_used_efd = NULL; > + } > + > + return ret; > +} > + > +static int parse_strtouint(const char *buf, > + unsigned long long max, unsigned int *value) > +{ > + int ret; > + > + ret = kstrtouint(skip_spaces(buf), 0, value); > + if (!ret && *value > max) > + ret = -EINVAL; > + return ret; > +} > + > +static ssize_t warn_used_blocks_efd_store(struct shmem_attr *a, > + struct shmem_sb_info *sbinfo, > + const char *buf, size_t count) > +{ > + unsigned int val; > + int ret; > + > + if (parse_strtouint(buf, -1ULL, &val)) > + return -EINVAL; > + > + ret = shmem_setup_warn_used_blocks_eventfd(sbinfo, val); > + > + return ret ? ret : count; > +} > + > +static struct shmem_attr > +shmem_attr_warn_used_blocks_efd = __ATTR_WO(warn_used_blocks_efd); > + > +static struct attribute *shmem_attrs[] = { > + &shmem_attr_warn_used_blocks_efd.attr, > + NULL, > +}; > + > +static ssize_t shmem_attr_show(struct kobject *kobj, > + struct attribute *attr, char *buf) > +{ > + struct shmem_sb_info *sbinfo = container_of(kobj, struct > shmem_sb_info, > + s_kobj); > + struct shmem_attr *a = container_of(attr, struct shmem_attr, attr); > + > + return a->show ? a->show(a, sbinfo, buf) : 0; > +} > + > +static ssize_t shmem_attr_store(struct kobject *kobj, > + struct attribute *attr, > + const char *buf, size_t len) > +{ > + struct shmem_sb_info *sbinfo = container_of(kobj, struct > shmem_sb_info, > + s_kobj); > + struct shmem_attr *a = container_of(attr, struct shmem_attr, attr); > + > + return a->store ? a->store(a, sbinfo, buf, len) : 0; > +} > + > +static void shmem_sb_release(struct kobject *kobj) > +{ > + struct shmem_sb_info *sbinfo = container_of(kobj, struct > shmem_sb_info, > + s_kobj); > + complete(&sbinfo->s_kobj_unregister); > +} > + > +static const struct sysfs_ops shmem_attr_ops = { > + .show = shmem_attr_show, > + .store = shmem_attr_store, > +}; > + > +static struct kobj_type shmem_ktype = { > + .default_attrs = shmem_attrs, > + .sysfs_ops = &shmem_attr_ops, > + .release = shmem_sb_release, > +}; > + > static int shmem_reserve_inode(struct super_block *sb) > { > struct shmem_sb_info *sbinfo = SHMEM_SB(sb); > @@ -1170,6 +1272,13 @@ repeat: > } > percpu_counter_inc(&sbinfo->used_blocks); > } > + if (sbinfo->warn_used) { > + if (percpu_counter_compare(&sbinfo->used_blocks, > + sbinfo->warn_used) >= 0) { > + if (sbinfo->warn_used_efd) > + eventfd_signal(sbinfo->warn_used_efd, > 1); > + } > + } > > page = shmem_alloc_page(gfp, info, index); > if (!page) { > @@ -2824,6 +2933,10 @@ static int shmem_parse_options(char *options, struct > shmem_sb_info *sbinfo, > mpol = NULL; > if (mpol_parse_str(value, &mpol)) > goto bad_val; > + } else if (!strcmp(this_char,"warn_used")) { > + sbinfo->warn_used = memparse(value, &rest); > + if (*rest) > + goto bad_val; > } else { > printk(KERN_ERR "tmpfs: Bad mount option %s\n", > this_char); > @@ -2984,6 +3097,13 @@ static void shmem_put_super(struct super_block *sb) > struct shmem_sb_info *sbinfo = SHMEM_SB(sb); > > percpu_counter_destroy(&sbinfo->used_blocks); > + if (sbinfo->warn_used_efd) { > + eventfd_ctx_put(sbinfo->warn_used_efd); > + sbinfo->warn_used_efd = NULL; > + } > + kobject_del(&sbinfo->s_kobj); > + kobject_put(&sbinfo->s_kobj); > + wait_for_completion(&sbinfo->s_kobj_unregister); > mpol_put(sbinfo->mpol); > kfree(sbinfo); > sb->s_fs_info = NULL; > @@ -2994,6 +3114,7 @@ int shmem_fill_super(struct super_block *sb, void > *data, int silent) > struct inode *inode; > struct shmem_sb_info *sbinfo; > int err = -ENOMEM; > + static unsigned int no; > > /* Round up to L1_CACHE_BYTES to resist false sharing */ > sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info), > @@ -3045,17 +3166,25 @@ int shmem_fill_super(struct super_block *sb, void > *data, int silent) > #ifdef CONFIG_TMPFS_POSIX_ACL > sb->s_flags |= MS_POSIXACL; > #endif > + sbinfo->s_kobj.kset = shmem_kset; > + init_completion(&sbinfo->s_kobj_unregister); > + err = kobject_init_and_add(&sbinfo->s_kobj, &shmem_ktype, NULL, > + "%s-%u", sb->s_id, no++); > + if (err) > + goto failed; > > inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, > VM_NORESERVE); > if (!inode) > - goto failed; > + goto failed_kobj; > inode->i_uid = sbinfo->uid; > inode->i_gid = sbinfo->gid; > sb->s_root = d_make_root(inode); > if (!sb->s_root) > - goto failed; > + goto failed_kobj; > return 0; > > +failed_kobj: > + kobject_del(&sbinfo->s_kobj); > failed: > shmem_put_super(sb); > return err; > @@ -3225,6 +3354,10 @@ int __init shmem_init(void) > if (shmem_inode_cachep) > return 0; > > + shmem_kset = kset_create_and_add("tmpfs", NULL, fs_kobj); > + if (!shmem_kset) > + return -ENOMEM; > + > error = bdi_init(&shmem_backing_dev_info); > if (error) > goto out4; > @@ -3255,6 +3388,7 @@ out3: > bdi_destroy(&shmem_backing_dev_info); > out4: > shm_mnt = ERR_PTR(error); > + kset_unregister(shmem_kset); > return error; > } > > -- > 1.9.1 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majord...@kvack.org. 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