These two interface were added in 091141a42 commit,
but now there is no place to call them.
The only user of fput/fget_many() was removed in commit
62906e89e63b ("io_uring: remove file batch-get optimisation").
A user of get_file_rcu_many() were removed in commit
f073531070d2 ("init: add an init_dup helper").
And replace atomic_long_sub/add to atomic_long_dec/inc
can improve performance.
Here are the test results of unixbench:
Cmd: ./Run -c 64 context1
Without patch:
System Benchmarks Partial Index BASELINE RESULT INDEX
Pipe-based Context Switching 4000.0 2798407.0 6996.0
========
System Benchmarks Index Score (Partial Only) 6996.0
With patch:
System Benchmarks Partial Index BASELINE RESULT INDEX
Pipe-based Context Switching 4000.0 3486268.8 8715.7
========
System Benchmarks Index Score (Partial Only) 8715.7
Signed-off-by: Gou Hao <[email protected]>
---
fs/file.c | 22 ++++++++--------------
fs/file_table.c | 9 ++-------
include/linux/file.h | 2 --
include/linux/fs.h | 4 +---
4 files changed, 11 insertions(+), 26 deletions(-)
diff --git a/fs/file.c b/fs/file.c
index 8627dacfc..49fbb6313 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -842,7 +842,7 @@ void do_close_on_exec(struct files_struct *files)
}
static struct file *__fget_files(struct files_struct *files, unsigned int fd,
- fmode_t mask, unsigned int refs)
+ fmode_t mask)
{
struct file *file;
@@ -856,7 +856,7 @@ loop:
*/
if (file->f_mode & mask)
file = NULL;
- else if (!get_file_rcu_many(file, refs))
+ else if (!get_file_rcu(file))
goto loop;
}
rcu_read_unlock();
@@ -864,26 +864,20 @@ loop:
return file;
}
-static inline struct file *__fget(unsigned int fd, fmode_t mask,
- unsigned int refs)
+static inline struct file *__fget(unsigned int fd, fmode_t mask)
{
- return __fget_files(current->files, fd, mask, refs);
-}
-
-struct file *fget_many(unsigned int fd, unsigned int refs)
-{
- return __fget(fd, FMODE_PATH, refs);
+ return __fget_files(current->files, fd, mask);
}
struct file *fget(unsigned int fd)
{
- return __fget(fd, FMODE_PATH, 1);
+ return __fget(fd, FMODE_PATH);
}
EXPORT_SYMBOL(fget);
struct file *fget_raw(unsigned int fd)
{
- return __fget(fd, 0, 1);
+ return __fget(fd, 0);
}
EXPORT_SYMBOL(fget_raw);
@@ -893,7 +887,7 @@ struct file *fget_task(struct task_struct *task, unsigned int fd)
task_lock(task);
if (task->files)
- file = __fget_files(task->files, fd, 0, 1);
+ file = __fget_files(task->files, fd, 0);
task_unlock(task);
return file;
@@ -962,7 +956,7 @@ static unsigned long __fget_light(unsigned int fd, fmode_t mask)
return 0;
return (unsigned long)file;
} else {
- file = __fget(fd, mask, 1);
+ file = __fget(fd, mask);
if (!file)
return 0;
return FDPUT_FPUT | (unsigned long)file;
diff --git a/fs/file_table.c b/fs/file_table.c
index 45437f8e1..10781a901 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -331,9 +331,9 @@ EXPORT_SYMBOL_GPL(flush_delayed_fput);
static DECLARE_DELAYED_WORK(delayed_fput_work, delayed_fput);
-void fput_many(struct file *file, unsigned int refs)
+void fput(struct file *file)
{
- if (atomic_long_sub_and_test(refs, &file->f_count)) {
+ if (atomic_long_dec_and_test(&file->f_count)) {
struct task_struct *task = current;
if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) {
@@ -352,11 +352,6 @@ void fput_many(struct file *file, unsigned int refs)
}
}
-void fput(struct file *file)
-{
- fput_many(file, 1);
-}
-
/*
* synchronous analog of fput(); for kernel threads that might be needed
* in some umount() (and thus can't use flush_delayed_fput() without
diff --git a/include/linux/file.h b/include/linux/file.h
index 51e830b4f..39704eae8 100644
--- a/include/linux/file.h
+++ b/include/linux/file.h
@@ -14,7 +14,6 @@
struct file;
extern void fput(struct file *);
-extern void fput_many(struct file *, unsigned int);
struct file_operations;
struct task_struct;
@@ -47,7 +46,6 @@ static inline void fdput(struct fd fd)
}
extern struct file *fget(unsigned int fd);
-extern struct file *fget_many(unsigned int fd, unsigned int refs);
extern struct file *fget_raw(unsigned int fd);
extern struct file *fget_task(struct task_struct *task, unsigned int fd);
extern unsigned long __fdget(unsigned int fd);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e7a633353..600470c2c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1015,9 +1015,7 @@ static inline struct file *get_file(struct file *f)
atomic_long_inc(&f->f_count);
return f;
}
-#define get_file_rcu_many(x, cnt) \
- atomic_long_add_unless(&(x)->f_count, (cnt), 0)
-#define get_file_rcu(x) get_file_rcu_many((x), 1)
+#define get_file_rcu(x) atomic_long_inc_not_zero(&(x)->f_count)
#define file_count(x) atomic_long_read(&(x)->f_count)
#define MAX_NON_LFS ((1UL<<31) - 1)
--
2.20.1
On Tue, Nov 02, 2021 at 10:46:48AM +0800, Gou Hao wrote:
> These two interface were added in 091141a42 commit,
> but now there is no place to call them.
>
> The only user of fput/fget_many() was removed in commit
> 62906e89e63b ("io_uring: remove file batch-get optimisation").
>
> A user of get_file_rcu_many() were removed in commit
> f073531070d2 ("init: add an init_dup helper").
>
> And replace atomic_long_sub/add to atomic_long_dec/inc
> can improve performance.
>
> Here are the test results of unixbench:
>
> Cmd: ./Run -c 64 context1
>
> Without patch:
> System Benchmarks Partial Index BASELINE RESULT INDEX
> Pipe-based Context Switching 4000.0 2798407.0 6996.0
> ========
> System Benchmarks Index Score (Partial Only) 6996.0
>
> With patch:
> System Benchmarks Partial Index BASELINE RESULT INDEX
> Pipe-based Context Switching 4000.0 3486268.8 8715.7
> ========
> System Benchmarks Index Score (Partial Only) 8715.7
>
> Signed-off-by: Gou Hao <[email protected]>
Rebased and applied, with deep apologies for having it fall through cracks
back in November.