tree d538f2cde041d28d7ca3320d0e88d592cb76abad
parent bc51b2a9193f917f2065313d9971d7d5e867bc81
author Eric Dumazet <edumazet@google.com> 1449169927 -0800
committer Al Viro <viro@zeniv.linux.org.uk> 1452326170 -0500

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>