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Subject[PATCH 09/13] proc: convert dentry flushing on exit to _print_integer()
Date
Benchmark fork+exit+waitpid 2^16 times:

6.579161299 seconds time elapsed ( +- 0.24% )
6.482729157 seconds time elapsed ( +- 0.42% )

-1.5%

Dentry flushing is very small part of exit(2), effects should be more
visible on a tiny 1-page process which doesn't uses libc.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
fs/proc/base.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 17666bd61ac8..79d2f7d72ad1 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -3022,11 +3022,11 @@ static const struct inode_operations proc_tgid_base_inode_operations = {
static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
{
struct dentry *dentry, *leader, *dir;
- char buf[10 + 1];
+ char buf[10];
struct qstr name;

- name.name = buf;
- name.len = snprintf(buf, sizeof(buf), "%u", pid);
+ name.name = _print_integer_u32(buf + sizeof(buf), pid);
+ name.len = buf + sizeof(buf) - (char *)name.name;
/* no ->d_hash() rejects on procfs */
dentry = d_hash_and_lookup(mnt->mnt_root, &name);
if (dentry) {
@@ -3037,8 +3037,8 @@ static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
if (pid == tgid)
return;

- name.name = buf;
- name.len = snprintf(buf, sizeof(buf), "%u", tgid);
+ name.name = _print_integer_u32(buf + sizeof(buf), tgid);
+ name.len = buf + sizeof(buf) - (char *)name.name;
leader = d_hash_and_lookup(mnt->mnt_root, &name);
if (!leader)
goto out;
@@ -3049,8 +3049,8 @@ static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
if (!dir)
goto out_put_leader;

- name.name = buf;
- name.len = snprintf(buf, sizeof(buf), "%u", pid);
+ name.name = _print_integer_u32(buf + sizeof(buf), pid);
+ name.len = buf + sizeof(buf) - (char *)name.name;
dentry = d_hash_and_lookup(dir, &name);
if (dentry) {
d_invalidate(dentry);
--
2.16.4
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