From c60991f8e187eb73dbea2375c08ccba8f544bd49 Mon Sep 17 00:00:00 2001 From: Liansen Zhai Date: Thu, 12 Oct 2023 17:03:30 +0800 Subject: [PATCH] cgroup, netclassid: on modifying netclassid in cgroup, only consider the main process. When modifying netclassid, the command("echo 0x100001 > net_cls.classid") will take more time on many threads of one process, because the process create many fds. for example, one process exists 28000 fds and 60000 threads, echo command will task 45 seconds. Now, we only consider the main process when exec "iterate_fd", and the time is about 52 milliseconds. Signed-off-by: Liansen Zhai Reviewed-by: Simon Horman Link: https://lore.kernel.org/r/20231012090330.29636-1-zhailiansen@kuaishou.com Signed-off-by: Jakub Kicinski --- net/core/netclassid_cgroup.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/core/netclassid_cgroup.c b/net/core/netclassid_cgroup.c index d6a70aeaa503..d22f0919821e 100644 --- a/net/core/netclassid_cgroup.c +++ b/net/core/netclassid_cgroup.c @@ -88,6 +88,12 @@ static void update_classid_task(struct task_struct *p, u32 classid) }; unsigned int fd = 0; + /* Only update the leader task, when many threads in this task, + * so it can avoid the useless traversal. + */ + if (p != p->group_leader) + return; + do { task_lock(p); fd = iterate_fd(p->files, fd, update_classid_sock, &ctx);