litmus-rt.git - The LITMUS^RT kernel.

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author	Bjoern B. Brandenburg <bbb@cs.unc.edu>	2010-11-20 20:58:56 -0500
committer	Bjoern B. Brandenburg <bbb@cs.unc.edu>	2010-12-06 09:37:18 -0500
commit	02a11ec22bf666f0ecc0b277649e59711b9b5500 (patch)
tree	7c968923926e382c22dc2623cd6c3e98d7264887 /kernel/time/tick-broadcast.c
parent	ee0e01a2e4d3b9266ca44a83271b22aa59b289f3 (diff)

sched: show length of runqueue clock deactivation in /proc/sched_debugwip-fix3

The runqueue clock update should obviously not be skipped for prolonged times (otherwise the consumed time is not correctly kept track of). This patch measures the time between setting and clearing the rq->skip_clock_update flag. The maximum observed value is exported in /proc/sched_debug.

Diffstat (limited to 'kernel/time/tick-broadcast.c')

0 files changed, 0 insertions, 0 deletions

/* * Resizable simple ram filesystem for Linux. * * Copyright (C) 2000 Linus Torvalds. * 2000 Transmeta Corp. * * Usage limits added by David Gibson, Linuxcare Australia. * This file is released under the GPL. */ /* * NOTE! This filesystem is probably most useful * not as a real filesystem, but as an example of * how virtual filesystems can be written. * * It doesn't get much simpler than this. Consider * that this file implements the full semantics of * a POSIX-compliant read-write filesystem. * * Note in particular how the filesystem does not * need to implement any data structures of its own * to keep track of the virtual data: using the VFS * caches is sufficient. */ #include <linux/fs.h> #include <linux/pagemap.h> #include <linux/highmem.h> #include <linux/time.h> #include <linux/init.h> #include <linux/string.h> #include <linux/backing-dev.h> #include <linux/ramfs.h> #include <linux/sched.h> #include <linux/parser.h> #include <linux/magic.h> #include <linux/slab.h> #include <asm/uaccess.h> #include "internal.h" #define RAMFS_DEFAULT_MODE 0755 static const struct super_operations ramfs_ops; static const struct inode_operations ramfs_dir_inode_operations; static struct backing_dev_info ramfs_backing_dev_info = { .name = "ramfs", .ra_pages = 0, /* No readahead */ .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_MAP_DIRECT | BDI_CAP_MAP_COPY | BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP, }; struct inode *ramfs_get_inode(struct super_block *sb, const struct inode *dir, umode_t mode, dev_t dev) { struct inode * inode = new_inode(sb); if (inode) { inode->i_ino = get_next_ino(); inode_init_owner(inode, dir, mode); inode->i_mapping->a_ops = &ramfs_aops; inode->i_mapping->backing_dev_info = &ramfs_backing_dev_info; mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER); mapping_set_unevictable(inode->i_mapping); inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; switch (mode & S_IFMT) { default: init_special_inode(inode, mode, dev); break; case S_IFREG: inode->i_op = &ramfs_file_inode_operations; inode->i_fop = &ramfs_file_operations; break; case S_IFDIR: inode->i_op = &ramfs_dir_inode_operations; inode->i_fop = &simple_dir_operations; /* directory inodes start off with i_nlink == 2 (for "." entry) */ inc_nlink(inode); break; case S_IFLNK: inode->i_op = &page_symlink_inode_operations; break; } } return inode; } /* * File creation. Allocate an inode, and we're done.. */ /* SMP-safe */ static int ramfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) { struct inode * inode = ramfs_get_inode(dir->i_sb, dir, mode, dev); int error = -ENOSPC; if (inode) { d_instantiate(dentry, inode); dget(dentry); /* Extra count - pin the dentry in core */ error = 0; dir->i_mtime = dir->i_ctime = CURRENT_TIME; } return error; } static int ramfs_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode) { int retval = ramfs_mknod(dir, dentry, mode | S_IFDIR, 0); if (!retval) inc_nlink(dir); return retval; } static int ramfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) { return ramfs_mknod(dir, dentry, mode | S_IFREG, 0); } static int ramfs_symlink(struct inode * dir, struct dentry *dentry, const char * symname) { struct inode *inode; int error = -ENOSPC; inode = ramfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0); if (inode) { int l = strlen(symname)+1; error = page_symlink(inode, symname, l); if (!error) { d_instantiate(dentry, inode); dget(dentry); dir->i_mtime = dir->i_ctime = CURRENT_TIME; } else iput(inode); } return error; } static const struct inode_operations ramfs_dir_inode_operations = { .create = ramfs_create, .lookup = simple_lookup, .link = simple_link, .unlink = simple_unlink, .symlink = ramfs_symlink, .mkdir = ramfs_mkdir, .rmdir = simple_rmdir, .mknod = ramfs_mknod, .rename = simple_rename, }; static const struct super_operations ramfs_ops = { .statfs = simple_statfs, .drop_inode = generic_delete_inode, .show_options = generic_show_options, }; struct ramfs_mount_opts { umode_t mode; }; enum { Opt_mode, Opt_err }; static const match_table_t tokens = { {Opt_mode, "mode=%o"}, {Opt_err, NULL} }; struct ramfs_fs_info { struct ramfs_mount_opts mount_opts; }; static int ramfs_parse_options(char *data, struct ramfs_mount_opts *opts) { substring_t args[MAX_OPT_ARGS]; int option; int token; char *p; opts->mode = RAMFS_DEFAULT_MODE; while ((p = strsep(&data, ",")) != NULL) { if (!*p) continue; token = match_token(p, tokens, args); switch (token) { case Opt_mode: if (match_octal(&args[0], &option)) return -EINVAL; opts->mode = option & S_IALLUGO; break; /* * We might like to report bad mount options here; * but traditionally ramfs has ignored all mount options, * and as it is used as a !CONFIG_SHMEM simple substitute * for tmpfs, better continue to ignore other mount options. */ } } return 0; } int ramfs_fill_super(struct super_block *sb, void *data, int silent) { struct ramfs_fs_info *fsi; struct inode *inode; int err; save_mount_options(sb, data); fsi = kzalloc(sizeof(struct ramfs_fs_info), GFP_KERNEL); sb->s_fs_info = fsi; if (!fsi) return -ENOMEM; err = ramfs_parse_options(data, &fsi->mount_opts); if (err) return err; sb->s_maxbytes = MAX_LFS_FILESIZE; sb->s_blocksize = PAGE_CACHE_SIZE; sb->s_blocksize_bits = PAGE_CACHE_SHIFT; sb->s_magic = RAMFS_MAGIC; sb->s_op = &ramfs_ops; sb->s_time_gran = 1; inode = ramfs_get_inode(sb, NULL, S_IFDIR | fsi->mount_opts.mode, 0); sb->s_root = d_make_root(inode); if (!sb->s_root) return -ENOMEM; return 0; } struct dentry *ramfs_mount(struct file_system_type *fs_type, int flags, const char *dev_name, void *data) { return mount_nodev(fs_type, flags, data, ramfs_fill_super); } static struct dentry *rootfs_mount(struct file_system_type *fs_type, int flags, const char *dev_name, void *data) { return mount_nodev(fs_type, flags|MS_NOUSER, data, ramfs_fill_super); } static void ramfs_kill_sb(struct super_block *sb) { kfree(sb->s_fs_info); kill_litter_super(sb); } static struct file_system_type ramfs_fs_type = { .name = "ramfs", .mount = ramfs_mount, .kill_sb = ramfs_kill_sb, .fs_flags = FS_USERNS_MOUNT, }; static struct file_system_type rootfs_fs_type = { .name = "rootfs", .mount = rootfs_mount, .kill_sb = kill_litter_super, }; static int __init init_ramfs_fs(void) { return register_filesystem(&ramfs_fs_type); } module_init(init_ramfs_fs) int __init init_rootfs(void) { int err; err = bdi_init(&ramfs_backing_dev_info); if (err) return err; err = register_filesystem(&rootfs_fs_type); if (err) bdi_destroy(&ramfs_backing_dev_info); return err; }


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