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authorMike Christie <michael.christie@oracle.com>2023-03-10 16:03:30 -0600
committerChristian Brauner <brauner@kernel.org>2023-03-23 12:45:36 +0100
commite297cd54b3f81d652456ae6cb93941fc6b5c6683 (patch)
tree26c7617cb30e3eeb9d4620d1ee0bde257e40b145 /kernel/Makefile
parent89c8e98d8cfb0656dbeb648572df5b13e372247d (diff)
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vhost_task: Allow vhost layer to use copy_process
Qemu will create vhost devices in the kernel which perform network, SCSI, etc IO and management operations from worker threads created by the kthread API. Because the kthread API does a copy_process on the kthreadd thread, the vhost layer has to use kthread_use_mm to access the Qemu thread's memory and cgroup_attach_task_all to add itself to the Qemu thread's cgroups, and it bypasses the RLIMIT_NPROC limit which can result in VMs creating more threads than the admin expected. This patch adds a new struct vhost_task which can be used instead of kthreads. They allow the vhost layer to use copy_process and inherit the userspace process's mm and cgroups, the task is accounted for under the userspace's nproc count and can be seen in its process tree, and other features like namespaces work and are inherited by default. Signed-off-by: Mike Christie <michael.christie@oracle.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'kernel/Makefile')
-rw-r--r--kernel/Makefile1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/Makefile b/kernel/Makefile
index 10ef068f598d..6fc72b3afbde 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -15,6 +15,7 @@ obj-y = fork.o exec_domain.o panic.o \
obj-$(CONFIG_USERMODE_DRIVER) += usermode_driver.o
obj-$(CONFIG_MODULES) += kmod.o
obj-$(CONFIG_MULTIUSER) += groups.o
+obj-$(CONFIG_VHOST_TASK) += vhost_task.o
ifdef CONFIG_FUNCTION_TRACER
# Do not trace internal ftrace files