[PATCH 4.9 085/108] proc: add a schedule point in proc_pid_readdir()

Greg Kroah-Hartman
2017-06-15T18:09:20Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 3ba4bceef23206349d4130ddf140819b365de7c8 ]

We have seen proc_pid_readdir() invocations holding cpu for more than 50
ms. Add a cond_resched() to be gentle with other tasks.

[akpm@linux-foundation.org: coding style fix]
Link: http://lkml.kernel.org/r/1484238380.15816.42.camel@edumazet-glaptop3.roam.corp.google.com
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/proc/base.c | 2 ++
1 file changed, 2 insertions(+)

--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -3181,6 +3181,8 @@ int proc_pid_readdir(struct file *file,
iter.tgid += 1, iter = next_tgid(ns, iter)) {
char name[PROC_NUMBUF];
int len;
+
+ cond_resched();
if (!has_pid_permissions(ns, iter.task, 2))
continue;