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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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d919b33daf
Now that "struct proc_ops" exist we can start putting there stuff which
could not fly with VFS "struct file_operations"...
Most of fs/proc/inode.c file is dedicated to make open/read/.../close
reliable in the event of disappearing /proc entries which usually happens
if module is getting removed. Files like /proc/cpuinfo which never
disappear simply do not need such protection.
Save 2 atomic ops, 1 allocation, 1 free per open/read/close sequence for such
"permanent" files.
Enable "permanent" flag for
/proc/cpuinfo
/proc/kmsg
/proc/modules
/proc/slabinfo
/proc/stat
/proc/sysvipc/*
/proc/swaps
More will come once I figure out foolproof way to prevent out module
authors from marking their stuff "permanent" for performance reasons
when it is not.
This should help with scalability: benchmark is "read /proc/cpuinfo R times
by N threads scattered over the system".
N R t, s (before) t, s (after)
-----------------------------------------------------
64 4096 1.582458 1.530502 -3.2%
256 4096 6.371926 6.125168 -3.9%
1024 4096 25.64888 24.47528 -4.6%
Benchmark source:
#include <chrono>
#include <iostream>
#include <thread>
#include <vector>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
const int NR_CPUS = sysconf(_SC_NPROCESSORS_ONLN);
int N;
const char *filename;
int R;
int xxx = 0;
int glue(int n)
{
cpu_set_t m;
CPU_ZERO(&m);
CPU_SET(n, &m);
return sched_setaffinity(0, sizeof(cpu_set_t), &m);
}
void f(int n)
{
glue(n % NR_CPUS);
while (*(volatile int *)&xxx == 0) {
}
for (int i = 0; i < R; i++) {
int fd = open(filename, O_RDONLY);
char buf[4096];
ssize_t rv = read(fd, buf, sizeof(buf));
asm volatile ("" :: "g" (rv));
close(fd);
}
}
int main(int argc, char *argv[])
{
if (argc < 4) {
std::cerr << "usage: " << argv[0] << ' ' << "N /proc/filename R
";
return 1;
}
N = atoi(argv[1]);
filename = argv[2];
R = atoi(argv[3]);
for (int i = 0; i < NR_CPUS; i++) {
if (glue(i) == 0)
break;
}
std::vector<std::thread> T;
T.reserve(N);
for (int i = 0; i < N; i++) {
T.emplace_back(f, i);
}
auto t0 = std::chrono::system_clock::now();
{
*(volatile int *)&xxx = 1;
for (auto& t: T) {
t.join();
}
}
auto t1 = std::chrono::system_clock::now();
std::chrono::duration<double> dt = t1 - t0;
std::cout << dt.count() << '
';
return 0;
}
P.S.:
Explicit randomization marker is added because adding non-function pointer
will silently disable structure layout randomization.
[akpm@linux-foundation.org: coding style fixes]
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Joe Perches <joe@perches.com>
Link: http://lkml.kernel.org/r/20200222201539.GA22576@avx2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
312 lines
8.8 KiB
C
312 lines
8.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/* Internal procfs definitions
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*
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* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <linux/proc_fs.h>
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#include <linux/proc_ns.h>
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#include <linux/refcount.h>
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#include <linux/spinlock.h>
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#include <linux/atomic.h>
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#include <linux/binfmts.h>
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#include <linux/sched/coredump.h>
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#include <linux/sched/task.h>
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struct ctl_table_header;
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struct mempolicy;
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/*
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* This is not completely implemented yet. The idea is to
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* create an in-memory tree (like the actual /proc filesystem
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* tree) of these proc_dir_entries, so that we can dynamically
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* add new files to /proc.
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*
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* parent/subdir are used for the directory structure (every /proc file has a
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* parent, but "subdir" is empty for all non-directory entries).
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* subdir_node is used to build the rb tree "subdir" of the parent.
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*/
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struct proc_dir_entry {
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/*
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* number of callers into module in progress;
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* negative -> it's going away RSN
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*/
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atomic_t in_use;
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refcount_t refcnt;
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struct list_head pde_openers; /* who did ->open, but not ->release */
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/* protects ->pde_openers and all struct pde_opener instances */
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spinlock_t pde_unload_lock;
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struct completion *pde_unload_completion;
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const struct inode_operations *proc_iops;
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union {
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const struct proc_ops *proc_ops;
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const struct file_operations *proc_dir_ops;
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};
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const struct dentry_operations *proc_dops;
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union {
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const struct seq_operations *seq_ops;
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int (*single_show)(struct seq_file *, void *);
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};
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proc_write_t write;
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void *data;
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unsigned int state_size;
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unsigned int low_ino;
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nlink_t nlink;
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kuid_t uid;
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kgid_t gid;
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loff_t size;
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struct proc_dir_entry *parent;
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struct rb_root subdir;
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struct rb_node subdir_node;
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char *name;
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umode_t mode;
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u8 flags;
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u8 namelen;
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char inline_name[];
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} __randomize_layout;
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#define SIZEOF_PDE ( \
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sizeof(struct proc_dir_entry) < 128 ? 128 : \
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sizeof(struct proc_dir_entry) < 192 ? 192 : \
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sizeof(struct proc_dir_entry) < 256 ? 256 : \
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sizeof(struct proc_dir_entry) < 512 ? 512 : \
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0)
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#define SIZEOF_PDE_INLINE_NAME (SIZEOF_PDE - sizeof(struct proc_dir_entry))
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static inline bool pde_is_permanent(const struct proc_dir_entry *pde)
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{
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return pde->flags & PROC_ENTRY_PERMANENT;
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}
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extern struct kmem_cache *proc_dir_entry_cache;
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void pde_free(struct proc_dir_entry *pde);
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union proc_op {
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int (*proc_get_link)(struct dentry *, struct path *);
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int (*proc_show)(struct seq_file *m,
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struct pid_namespace *ns, struct pid *pid,
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struct task_struct *task);
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const char *lsm;
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};
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struct proc_inode {
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struct pid *pid;
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unsigned int fd;
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union proc_op op;
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struct proc_dir_entry *pde;
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struct ctl_table_header *sysctl;
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struct ctl_table *sysctl_entry;
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struct hlist_node sibling_inodes;
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const struct proc_ns_operations *ns_ops;
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struct inode vfs_inode;
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} __randomize_layout;
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/*
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* General functions
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*/
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static inline struct proc_inode *PROC_I(const struct inode *inode)
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{
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return container_of(inode, struct proc_inode, vfs_inode);
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}
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static inline struct proc_dir_entry *PDE(const struct inode *inode)
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{
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return PROC_I(inode)->pde;
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}
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static inline void *__PDE_DATA(const struct inode *inode)
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{
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return PDE(inode)->data;
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}
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static inline struct pid *proc_pid(const struct inode *inode)
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{
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return PROC_I(inode)->pid;
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}
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static inline struct task_struct *get_proc_task(const struct inode *inode)
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{
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return get_pid_task(proc_pid(inode), PIDTYPE_PID);
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}
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void task_dump_owner(struct task_struct *task, umode_t mode,
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kuid_t *ruid, kgid_t *rgid);
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unsigned name_to_int(const struct qstr *qstr);
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/*
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* Offset of the first process in the /proc root directory..
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*/
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#define FIRST_PROCESS_ENTRY 256
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/* Worst case buffer size needed for holding an integer. */
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#define PROC_NUMBUF 13
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/*
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* array.c
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*/
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extern const struct file_operations proc_tid_children_operations;
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extern void proc_task_name(struct seq_file *m, struct task_struct *p,
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bool escape);
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extern int proc_tid_stat(struct seq_file *, struct pid_namespace *,
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struct pid *, struct task_struct *);
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extern int proc_tgid_stat(struct seq_file *, struct pid_namespace *,
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struct pid *, struct task_struct *);
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extern int proc_pid_status(struct seq_file *, struct pid_namespace *,
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struct pid *, struct task_struct *);
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extern int proc_pid_statm(struct seq_file *, struct pid_namespace *,
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struct pid *, struct task_struct *);
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/*
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* base.c
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*/
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extern const struct dentry_operations pid_dentry_operations;
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extern int pid_getattr(const struct path *, struct kstat *, u32, unsigned int);
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extern int proc_setattr(struct dentry *, struct iattr *);
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extern void proc_pid_evict_inode(struct proc_inode *);
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extern struct inode *proc_pid_make_inode(struct super_block *, struct task_struct *, umode_t);
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extern void pid_update_inode(struct task_struct *, struct inode *);
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extern int pid_delete_dentry(const struct dentry *);
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extern int proc_pid_readdir(struct file *, struct dir_context *);
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struct dentry *proc_pid_lookup(struct dentry *, unsigned int);
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extern loff_t mem_lseek(struct file *, loff_t, int);
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/* Lookups */
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typedef struct dentry *instantiate_t(struct dentry *,
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struct task_struct *, const void *);
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bool proc_fill_cache(struct file *, struct dir_context *, const char *, unsigned int,
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instantiate_t, struct task_struct *, const void *);
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/*
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* generic.c
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*/
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struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode,
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struct proc_dir_entry **parent, void *data);
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struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
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struct proc_dir_entry *dp);
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extern struct dentry *proc_lookup(struct inode *, struct dentry *, unsigned int);
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struct dentry *proc_lookup_de(struct inode *, struct dentry *, struct proc_dir_entry *);
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extern int proc_readdir(struct file *, struct dir_context *);
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int proc_readdir_de(struct file *, struct dir_context *, struct proc_dir_entry *);
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static inline struct proc_dir_entry *pde_get(struct proc_dir_entry *pde)
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{
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refcount_inc(&pde->refcnt);
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return pde;
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}
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extern void pde_put(struct proc_dir_entry *);
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static inline bool is_empty_pde(const struct proc_dir_entry *pde)
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{
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return S_ISDIR(pde->mode) && !pde->proc_iops;
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}
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extern ssize_t proc_simple_write(struct file *, const char __user *, size_t, loff_t *);
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/*
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* inode.c
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*/
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struct pde_opener {
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struct list_head lh;
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struct file *file;
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bool closing;
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struct completion *c;
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} __randomize_layout;
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extern const struct inode_operations proc_link_inode_operations;
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extern const struct inode_operations proc_pid_link_inode_operations;
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extern const struct super_operations proc_sops;
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void proc_init_kmemcache(void);
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void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock);
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void set_proc_pid_nlink(void);
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extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *);
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extern void proc_entry_rundown(struct proc_dir_entry *);
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/*
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* proc_namespaces.c
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*/
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extern const struct inode_operations proc_ns_dir_inode_operations;
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extern const struct file_operations proc_ns_dir_operations;
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/*
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* proc_net.c
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*/
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extern const struct file_operations proc_net_operations;
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extern const struct inode_operations proc_net_inode_operations;
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#ifdef CONFIG_NET
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extern int proc_net_init(void);
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#else
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static inline int proc_net_init(void) { return 0; }
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#endif
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/*
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* proc_self.c
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*/
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extern int proc_setup_self(struct super_block *);
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/*
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* proc_thread_self.c
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*/
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extern int proc_setup_thread_self(struct super_block *);
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extern void proc_thread_self_init(void);
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/*
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* proc_sysctl.c
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*/
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#ifdef CONFIG_PROC_SYSCTL
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extern int proc_sys_init(void);
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extern void proc_sys_evict_inode(struct inode *inode,
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struct ctl_table_header *head);
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#else
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static inline void proc_sys_init(void) { }
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static inline void proc_sys_evict_inode(struct inode *inode,
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struct ctl_table_header *head) { }
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#endif
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/*
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* proc_tty.c
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*/
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#ifdef CONFIG_TTY
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extern void proc_tty_init(void);
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#else
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static inline void proc_tty_init(void) {}
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#endif
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/*
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* root.c
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*/
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extern struct proc_dir_entry proc_root;
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extern void proc_self_init(void);
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/*
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* task_[no]mmu.c
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*/
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struct mem_size_stats;
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struct proc_maps_private {
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struct inode *inode;
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struct task_struct *task;
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struct mm_struct *mm;
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#ifdef CONFIG_MMU
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struct vm_area_struct *tail_vma;
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#endif
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#ifdef CONFIG_NUMA
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struct mempolicy *task_mempolicy;
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#endif
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} __randomize_layout;
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struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode);
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extern const struct file_operations proc_pid_maps_operations;
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extern const struct file_operations proc_pid_numa_maps_operations;
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extern const struct file_operations proc_pid_smaps_operations;
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extern const struct file_operations proc_pid_smaps_rollup_operations;
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extern const struct file_operations proc_clear_refs_operations;
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extern const struct file_operations proc_pagemap_operations;
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extern unsigned long task_vsize(struct mm_struct *);
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extern unsigned long task_statm(struct mm_struct *,
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unsigned long *, unsigned long *,
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unsigned long *, unsigned long *);
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extern void task_mem(struct seq_file *, struct mm_struct *);
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