linux/ipc
Giuseppe Scrivano e1eb26fa62 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 <sched.h>
    #include <error.h>
    #include <errno.h>
    #include <stdlib.h>

    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 <gscrivan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Link: http://lkml.kernel.org/r/20200225145419.527994-1-gscrivan@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-08 11:05:56 -07:00
..
compat.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ipc_sysctl.c sysctl: pass kernel pointers to ->proc_handler 2020-04-27 02:07:40 -04:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mq_sysctl.c sysctl: pass kernel pointers to ->proc_handler 2020-04-27 02:07:40 -04:00
mqueue.c ipc/mqueue.c: change __do_notify() to bypass check_kill_permission() 2020-05-07 19:27:20 -07:00
msg.c ipc/msg: add missing annotation for freeque() 2020-06-08 11:05:55 -07:00
msgutil.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 52 2019-05-24 17:36:42 +02:00
namespace.c ipc/namespace.c: use a work queue to free_ipc 2020-06-08 11:05:56 -07:00
sem.c Revert "ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()" 2020-02-21 11:22:15 -08:00
shm.c ipc/shm.c: make compat_ksys_shmctl() static 2020-04-07 10:43:45 -07:00
syscall.c y2038: remove CONFIG_64BIT_TIME 2019-11-15 14:38:27 +01:00
util.c ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-14 10:00:35 -07:00
util.h ipc: fix sparc64 ipc() wrapper 2019-09-07 21:42:25 +02:00