mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-18 07:47:50 +07:00
2a4419b5b2
fs: fs_struct rwlock to spinlock struct fs_struct.lock is an rwlock with the read-side used to protect root and pwd members while taking references to them. Taking a reference to a path typically requires just 2 atomic ops, so the critical section is very small. Parallel read-side operations would have cacheline contention on the lock, the dentry, and the vfsmount cachelines, so the rwlock is unlikely to ever give a real parallelism increase. Replace it with a spinlock to avoid one or two atomic operations in typical path lookup fastpath. Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
52 lines
1.1 KiB
C
52 lines
1.1 KiB
C
#ifndef _LINUX_FS_STRUCT_H
|
|
#define _LINUX_FS_STRUCT_H
|
|
|
|
#include <linux/path.h>
|
|
|
|
struct fs_struct {
|
|
int users;
|
|
spinlock_t lock;
|
|
int umask;
|
|
int in_exec;
|
|
struct path root, pwd;
|
|
};
|
|
|
|
extern struct kmem_cache *fs_cachep;
|
|
|
|
extern void exit_fs(struct task_struct *);
|
|
extern void set_fs_root(struct fs_struct *, struct path *);
|
|
extern void set_fs_pwd(struct fs_struct *, struct path *);
|
|
extern struct fs_struct *copy_fs_struct(struct fs_struct *);
|
|
extern void free_fs_struct(struct fs_struct *);
|
|
extern void daemonize_fs_struct(void);
|
|
extern int unshare_fs_struct(void);
|
|
|
|
static inline void get_fs_root(struct fs_struct *fs, struct path *root)
|
|
{
|
|
spin_lock(&fs->lock);
|
|
*root = fs->root;
|
|
path_get(root);
|
|
spin_unlock(&fs->lock);
|
|
}
|
|
|
|
static inline void get_fs_pwd(struct fs_struct *fs, struct path *pwd)
|
|
{
|
|
spin_lock(&fs->lock);
|
|
*pwd = fs->pwd;
|
|
path_get(pwd);
|
|
spin_unlock(&fs->lock);
|
|
}
|
|
|
|
static inline void get_fs_root_and_pwd(struct fs_struct *fs, struct path *root,
|
|
struct path *pwd)
|
|
{
|
|
spin_lock(&fs->lock);
|
|
*root = fs->root;
|
|
path_get(root);
|
|
*pwd = fs->pwd;
|
|
path_get(pwd);
|
|
spin_unlock(&fs->lock);
|
|
}
|
|
|
|
#endif /* _LINUX_FS_STRUCT_H */
|