hulk inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I8OHM4?from=project-issue CVE: NA

----------------------------------------

In order to analyse the IO performance when using buffer IO, it's useful to obtain the number of dirty pages for each inode in the filesystem.

This feature depends on 'CONFIG_DIRTY_PAGES'. It creates 3 interfaces by using procfs. /proc/dirty/buffer_size for buffer allocation and release, /proc/dirty/page_threshold to filter result and /proc/dirty/dirty_list to get dirty pages.

Signed-off-by: Zizhi Wo wozizhi@huawei.com --- arch/arm64/configs/openeuler_defconfig | 1 + arch/x86/configs/openeuler_defconfig | 1 + fs/Kconfig | 13 + fs/Makefile | 1 + fs/dirty_pages.c | 355 +++++++++++++++++++++++++ 5 files changed, 371 insertions(+) create mode 100644 fs/dirty_pages.c

diff --git a/arch/arm64/configs/openeuler_defconfig b/arch/arm64/configs/openeuler_defconfig index 66737e8c8673..677b4cc4668a 100644 --- a/arch/arm64/configs/openeuler_defconfig +++ b/arch/arm64/configs/openeuler_defconfig @@ -6924,6 +6924,7 @@ CONFIG_PROC_PAGE_MONITOR=y CONFIG_PROC_CHILDREN=y CONFIG_KERNFS=y CONFIG_SYSFS=y +CONFIG_DIRTY_PAGES=y CONFIG_TMPFS=y CONFIG_TMPFS_POSIX_ACL=y CONFIG_TMPFS_XATTR=y diff --git a/arch/x86/configs/openeuler_defconfig b/arch/x86/configs/openeuler_defconfig index fcbef6c06587..c16cdb7b2596 100644 --- a/arch/x86/configs/openeuler_defconfig +++ b/arch/x86/configs/openeuler_defconfig @@ -8120,6 +8120,7 @@ CONFIG_PROC_PID_ARCH_STATUS=y CONFIG_PROC_CPU_RESCTRL=y CONFIG_KERNFS=y CONFIG_SYSFS=y +CONFIG_DIRTY_PAGES=y CONFIG_TMPFS=y CONFIG_TMPFS_POSIX_ACL=y CONFIG_TMPFS_XATTR=y diff --git a/fs/Kconfig b/fs/Kconfig index 7c9d45ba9b0f..6dc83223c61b 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -170,6 +170,19 @@ source "fs/proc/Kconfig" source "fs/kernfs/Kconfig" source "fs/sysfs/Kconfig"

+config DIRTY_PAGES + bool "Dumps the number of dirty pages of each file" + depends on PROC_FS + default y + help + This config supports the rendering of dirty page data to the user, + which may be useful to analyze the IO performance when using buffer + IO. + + It create 3 interfaces by using procfs. /proc/dirty/buffer_size for + buffer allocation and release; /proc/dirty/page_threshold to filter + result; /proc/dirty/dirty_list to get dirty pages. + config TMPFS bool "Tmpfs virtual memory file system support (former shm fs)" depends on SHMEM diff --git a/fs/Makefile b/fs/Makefile index bb6164200a39..cc4735c23c32 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -44,6 +44,7 @@ obj-$(CONFIG_FS_POSIX_ACL) += posix_acl.o obj-$(CONFIG_NFS_COMMON) += nfs_common/ obj-$(CONFIG_COREDUMP) += coredump.o obj-$(CONFIG_SYSCTL) += drop_caches.o sysctls.o +obj-$(CONFIG_DIRTY_PAGES) += dirty_pages.o

obj-$(CONFIG_FHANDLE) += fhandle.o obj-$(CONFIG_CGROUP_FILES) += filescontrol.o diff --git a/fs/dirty_pages.c b/fs/dirty_pages.c new file mode 100644 index 000000000000..d0aea022b68b --- /dev/null +++ b/fs/dirty_pages.c @@ -0,0 +1,355 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include <linux/uaccess.h> +#include <linux/pagemap.h> +#include <linux/pagevec.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/sched.h> +#include <linux/proc_fs.h> +#include <linux/kdev_t.h> +#include <linux/vmalloc.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include "internal.h" + +#define DIRTY_ROOT "dirty" /* proc root directory name */ +#define DIRTY_BUFFER_SIZE "buffer_size" /* proc file to control buffer */ +#define DIRTY_PAGES "dirty_list" /* proc file to obtain diry pages */ +#define DIRTY_LIMIT "page_threshold" /* proc file to filter result */ +#define MAX_BUF_NUM 102400 /* max buffer num in number of pages */ +#define TERM_STR "terminated\n" /* tail string for overflowed buffer */ +#define UNKNOW_STR "unknown" /* for unknown file name or fs type */ + +static char *buf_dirty; /* buffer to store number of dirty pages */ +static unsigned long buf_size; /* size of buffer in bytes */ +static unsigned long buf_num; /* size of buffer in number of pages */ +static unsigned long buf_limit; /* filter threshold of dirty pages */ +unsigned long lock_word; /* for exclusive access to buffer */ + +static bool dirty_pages_lock(void) +{ + if (xchg(&lock_word, 1) == 1) + return false; + return true; +} + +static void dirty_pages_unlock(void) +{ + lock_word = 0; +} + +static unsigned long dump_dirtypages_inode(struct inode *inode) +{ + XA_STATE(xas, &inode->i_mapping->i_pages, 0); + unsigned long pages = 0; + void *page; + + if (!mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) + return 0; + + xas_lock_irq(&xas); + xas_for_each_marked(&xas, page, (pgoff_t)-1, PAGECACHE_TAG_DIRTY) { + if (++pages % XA_CHECK_SCHED) + continue; + + xas_pause(&xas); + xas_unlock_irq(&xas); + cond_resched(); + xas_lock_irq(&xas); + } + xas_unlock_irq(&xas); + + return pages; +} + +static char *inode_filename(struct inode *inode) +{ + char *path; + static char buf[PATH_MAX]; + struct dentry *dentry; + + dentry = d_find_alias(inode); + if (!dentry) + return UNKNOW_STR; + + path = dentry_path_raw(dentry, buf, PATH_MAX); + dput(dentry); + + return IS_ERR_OR_NULL(path) ? UNKNOW_STR : path; +} + +static const char *sb_fstype(struct super_block *sb) +{ + if (sb->s_type && sb->s_type->name) + return sb->s_type->name; + else + return UNKNOW_STR; +} + +static inline bool is_sb_writable(struct super_block *sb) +{ + if (sb_rdonly(sb)) + return false; + + if (sb->s_writers.frozen == SB_FREEZE_COMPLETE) + return false; + + return true; +} + +/* + * dump_dirtypages_sb - dump the dirty pages of each inode in the sb + * @sb the super block + * @m the seq_file witch is initialized in proc_dpages_open + * + * For each inode in the sb, call dump_dirtypages_pages to get the number + * of dirty pages. And use seq_printf to store the result in the buffer + * if it's not less than the threshold. The inode in unusual state will + * be skipped. + */ +static void dump_dirtypages_sb(struct super_block *sb, struct seq_file *m) +{ + struct inode *inode, *toput_inode = NULL; + unsigned long limit; + + if (!is_sb_writable(sb) || !sb->s_bdev) + return; + + limit = READ_ONCE(buf_limit); + spin_lock(&sb->s_inode_list_lock); + list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { + unsigned long dirty_pages; + + spin_lock(&inode->i_lock); + if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) { + spin_unlock(&inode->i_lock); + continue; + } + + __iget(inode); + spin_unlock(&inode->i_lock); + spin_unlock(&sb->s_inode_list_lock); + + dirty_pages = dump_dirtypages_inode(inode); + if (!dirty_pages || dirty_pages < limit) + goto skip; + + seq_printf(m, "FSType: %s, Dev ID: %u(%u:%u) ino %lu, dirty pages %lu, path %s\n", + sb_fstype(sb), sb->s_dev, MAJOR(sb->s_dev), + MINOR(sb->s_dev), inode->i_ino, dirty_pages, + inode_filename(inode)); + + if (seq_has_overflowed(m)) { + /* keep size > count to avoid overflow in seq_read_iter() */ + m->size += strlen(TERM_STR) + 1; + seq_puts(m, TERM_STR); + iput(inode); + iput(toput_inode); + return; + } +skip: + iput(toput_inode); + toput_inode = inode; + cond_resched(); + spin_lock(&sb->s_inode_list_lock); + } + spin_unlock(&sb->s_inode_list_lock); + iput(toput_inode); +} + +static int proc_dpages_show(struct seq_file *m, void *v) +{ + iterate_supers((void *)dump_dirtypages_sb, (void *)m); + return 0; +} + +static int proc_dpages_open(struct inode *inode, struct file *filp) +{ + int ret; + struct seq_file *m; + + if (!dirty_pages_lock()) + return -EBUSY; + + if (buf_dirty == NULL || buf_size == 0) { + pr_warn("please allocate buffer before getting dirty pages\n"); + dirty_pages_unlock(); + return -ENOMEM; + } + + ret = single_open(filp, proc_dpages_show, NULL); + if (ret) { + dirty_pages_unlock(); + return ret; + } + + m = (struct seq_file *)filp->private_data; + memset(buf_dirty, 0, buf_size); + m->size = buf_size - (strlen(TERM_STR) + 1); + m->buf = buf_dirty; + + return 0; +} + +static int proc_dpages_release(struct inode *inode, struct file *file) +{ + struct seq_file *m = file->private_data; + + /* we don't want to free the buf */ + m->buf = NULL; + dirty_pages_unlock(); + return single_release(inode, file); +} + +static void free_buf_dirty(void) +{ + if (!buf_dirty) + return; + + vfree(buf_dirty); + buf_dirty = NULL; + buf_size = 0; + WRITE_ONCE(buf_num, 0); +} + +static int proc_buffer_show(struct seq_file *m, void *v) +{ + seq_printf(m, "%lu\n", READ_ONCE(buf_num)); + return 0; +} + +static int proc_buffer_open(struct inode *inode, struct file *filp) +{ + int ret; + + if (((filp->f_flags & O_ACCMODE) != O_RDONLY) && !dirty_pages_lock()) + return -EBUSY; + + ret = single_open(filp, proc_buffer_show, NULL); + if (ret) + dirty_pages_unlock(); + + return ret; +} + +static ssize_t proc_buffer_write(struct file *filp, const char __user *buf, + size_t count, loff_t *offp) +{ + int ret; + unsigned long new_buf_num, new_buf_size; + char *new_buf_dirty; + + ret = kstrtoul_from_user(buf, count, 10, &new_buf_num); + if (ret != 0 || new_buf_num > MAX_BUF_NUM) + return -EINVAL; + + if (new_buf_num == buf_num) + return count; + + if (new_buf_num == 0) { + free_buf_dirty(); + return count; + } + + new_buf_size = PAGE_SIZE * new_buf_num; + new_buf_dirty = vzalloc(new_buf_size); + if (!new_buf_dirty) + return -ENOMEM; + + free_buf_dirty(); + buf_dirty = new_buf_dirty; + buf_size = new_buf_size; + WRITE_ONCE(buf_num, new_buf_num); + + return count; +} + +static int proc_buffer_release(struct inode *inode, struct file *filp) +{ + if ((filp->f_flags & O_ACCMODE) != O_RDONLY) + dirty_pages_unlock(); + return single_release(inode, filp); +} + +static int proc_limit_show(struct seq_file *m, void *v) +{ + seq_printf(m, "%lu\n", READ_ONCE(buf_limit)); + return 0; +} + +static int proc_limit_open(struct inode *inode, struct file *filp) +{ + return single_open(filp, proc_limit_show, NULL); +} + +static ssize_t proc_limit_write(struct file *filp, const char __user *buf, + size_t count, loff_t *offp) +{ + int ret; + unsigned long limit; + + ret = kstrtoul_from_user(buf, count, 10, &limit); + if (ret != 0) + return ret; + + WRITE_ONCE(buf_limit, limit); + + return count; +} + +static const struct proc_ops proc_dpages_operations = { + .proc_open = proc_dpages_open, + .proc_read = seq_read, + .proc_release = proc_dpages_release, +}; + +static const struct proc_ops proc_buffer_operations = { + .proc_open = proc_buffer_open, + .proc_read = seq_read, + .proc_write = proc_buffer_write, + .proc_lseek = seq_lseek, + .proc_release = proc_buffer_release, +}; + +static const struct proc_ops proc_limit_operations = { + .proc_open = proc_limit_open, + .proc_read = seq_read, + .proc_write = proc_limit_write, + .proc_lseek = seq_lseek, + .proc_release = single_release, +}; + +static int __init dpages_proc_init(void) +{ + struct proc_dir_entry *dirty_dir; + + dirty_dir = proc_mkdir(DIRTY_ROOT, NULL); + if (!dirty_dir) + return -ENOMEM; + + if (!proc_create(DIRTY_PAGES, 0440, dirty_dir, &proc_dpages_operations)) + goto fail_pages; + + if (!proc_create(DIRTY_BUFFER_SIZE, 0640, dirty_dir, + &proc_buffer_operations)) + goto fail_switch; + + if (!proc_create(DIRTY_LIMIT, 0640, dirty_dir, &proc_limit_operations)) + goto fail_limit; + + return 0; + +fail_limit: + remove_proc_entry(DIRTY_BUFFER_SIZE, dirty_dir); +fail_switch: + remove_proc_entry(DIRTY_PAGES, dirty_dir); +fail_pages: + remove_proc_entry(DIRTY_ROOT, NULL); + return -ENOMEM; +} + +subsys_initcall(dpages_proc_init);