From e1eb26fa62d04ec0955432be1aa8722a97cb52e7 Mon Sep 17 00:00:00 2001 From: Giuseppe Scrivano Date: Sun, 7 Jun 2020 21:40:10 -0700 Subject: ipc/namespace.c: use a work queue to free_ipc the reason is to avoid a delay caused by the synchronize_rcu() call in kern_umount() when the mqueue mount is freed. the code: #define _GNU_SOURCE #include #include #include #include int main() { int i; for (i = 0; i < 1000; i++) if (unshare(CLONE_NEWIPC) < 0) error(EXIT_FAILURE, errno, "unshare"); } goes from Command being timed: "./ipc-namespace" User time (seconds): 0.00 System time (seconds): 0.06 Percent of CPU this job got: 0% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:08.05 to Command being timed: "./ipc-namespace" User time (seconds): 0.00 System time (seconds): 0.02 Percent of CPU this job got: 96% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.03 Signed-off-by: Giuseppe Scrivano Signed-off-by: Andrew Morton Reviewed-by: Paul E. McKenney Reviewed-by: Waiman Long Cc: Davidlohr Bueso Cc: Manfred Spraul Link: http://lkml.kernel.org/r/20200225145419.527994-1-gscrivan@redhat.com Signed-off-by: Linus Torvalds --- include/linux/ipc_namespace.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/ipc_namespace.h') diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h index c309f43bde45..a06a78c67f19 100644 --- a/include/linux/ipc_namespace.h +++ b/include/linux/ipc_namespace.h @@ -68,6 +68,8 @@ struct ipc_namespace { struct user_namespace *user_ns; struct ucounts *ucounts; + struct llist_node mnt_llist; + struct ns_common ns; } __randomize_layout; -- cgit v1.2.3-59-g8ed1b