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From: Alexey Dobriyan <adobriyan@gmail.com>
To: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org, Alexey Dobriyan <adobriyan@gmail.com>
Subject: [PATCH 06/13] proc: convert /proc/self to _print_integer()
Date: Tue, 28 Aug 2018 02:14:56 +0300	[thread overview]
Message-ID: <20180827231503.26899-6-adobriyan@gmail.com> (raw)
In-Reply-To: <20180827231503.26899-1-adobriyan@gmail.com>

Benchmark readlink("/proc/self") 2^23 times:

	8.205992458 seconds time elapsed ( +-  0.15% )
	7.535168869 seconds time elapsed ( +-  0.09% )

	-8.2%

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
 fs/proc/self.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/proc/self.c b/fs/proc/self.c
index 127265e5c55f..b2279412237b 100644
--- a/fs/proc/self.c
+++ b/fs/proc/self.c
@@ -14,6 +14,7 @@ static const char *proc_self_get_link(struct dentry *dentry,
 {
 	struct pid_namespace *ns = proc_pid_ns(inode);
 	pid_t tgid = task_tgid_nr_ns(current, ns);
+	char buf[10], *p = buf + sizeof(buf);
 	char *name;
 
 	if (!tgid)
@@ -22,7 +23,11 @@ static const char *proc_self_get_link(struct dentry *dentry,
 	name = kmalloc(10 + 1, dentry ? GFP_KERNEL : GFP_ATOMIC);
 	if (unlikely(!name))
 		return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
-	sprintf(name, "%u", tgid);
+
+	p = _print_integer_u32(p, tgid);
+	memcpy(name, p, buf + sizeof(buf) - p);
+	name[buf + sizeof(buf) - p] = '\0';
+
 	set_delayed_call(done, kfree_link, name);
 	return name;
 }
-- 
2.16.4


  parent reply	other threads:[~2018-08-27 23:15 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-27 23:14 [PATCH 01/13] seq_file: rewrite seq_puts() in terms of seq_write() Alexey Dobriyan
2018-08-27 23:14 ` [PATCH 02/13] proc: apply seq_puts() whenever possible Alexey Dobriyan
2018-08-27 23:14 ` [PATCH 03/13] proc: rename "p" variable in proc_readfd_common() Alexey Dobriyan
2018-08-27 23:14 ` [PATCH 04/13] proc: rename "p" variable in proc_map_files_readdir() Alexey Dobriyan
2018-08-27 23:14 ` [PATCH 05/13] proc: new and improved way to print decimals Alexey Dobriyan
2018-08-27 23:14 ` Alexey Dobriyan [this message]
2018-08-29  9:50   ` [PATCH 06/13] proc: convert /proc/self to _print_integer() David Laight
2018-08-30 13:13     ` Alexey Dobriyan
2018-08-27 23:14 ` [PATCH 07/13] proc: convert /proc/thread-self " Alexey Dobriyan
2018-08-27 23:14 ` [PATCH 08/13] proc: convert /proc/*/fd " Alexey Dobriyan
2018-08-27 23:14 ` [PATCH 09/13] proc: convert dentry flushing on exit " Alexey Dobriyan
2018-08-27 23:15 ` [PATCH 10/13] proc: convert readdir /proc " Alexey Dobriyan
2018-08-27 23:15 ` [PATCH 11/13] proc: readdir /proc/*/task Alexey Dobriyan
2018-08-28 12:36   ` Ahmed S. Darwish
2018-08-28 13:04     ` Ahmed S. Darwish
2018-08-28 19:35       ` Alexey Dobriyan
2018-08-29 23:43         ` Andrew Morton
2018-08-30 13:20           ` Alexey Dobriyan
2018-08-28 19:31     ` Alexey Dobriyan
2018-08-27 23:15 ` [PATCH 12/13] proc: convert /proc/*/statm to _print_integer() Alexey Dobriyan
2018-08-27 23:15 ` [PATCH 13/13] proc: convert /proc/*/task/*/children " Alexey Dobriyan
2018-08-28 18:24 ` [PATCH 01/13] seq_file: rewrite seq_puts() in terms of seq_write() Joe Perches
2018-08-28 20:48   ` Joe Perches
2018-09-03 14:17 ` Alexey Dobriyan

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