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authorEric Dumazet <edumazet@google.com>2015-12-03 11:12:07 -0800
committerAl Viro <viro@zeniv.linux.org.uk>2016-01-09 02:56:10 -0500
commit3cc4a84e026e8d61b7ffe4a7367ed09a555f2c5b (patch)
treed538f2cde041d28d7ca3320d0e88d592cb76abad /fs/proc
parentbc51b2a9193f917f2065313d9971d7d5e867bc81 (diff)
downloadlinux-3cc4a84e026e8d61b7ffe4a7367ed09a555f2c5b.tar.bz2
proc: add a reschedule point in proc_readfd_common()
User can pass an arbitrary large buffer to getdents(). It is typically a 32KB buffer used by libc scandir() implementation. When scanning /proc/{pid}/fd, we can hold cpu way too long, so add a cond_resched() to be kind with other tasks. We've seen latencies of more than 50ms on real workloads. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/fd.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/proc/fd.c b/fs/proc/fd.c
index 3c2a915c695a..56afa5ef08f2 100644
--- a/fs/proc/fd.c
+++ b/fs/proc/fd.c
@@ -258,6 +258,7 @@ static int proc_readfd_common(struct file *file, struct dir_context *ctx,
name, len, instantiate, p,
(void *)(unsigned long)fd))
goto out_fd_loop;
+ cond_resched();
rcu_read_lock();
}
rcu_read_unlock();