criu/plugin: Introduce new plugin hooks PAUSE_DEVICES and CHECKPOINT_DEVICES to be used during pstree collection

PAUSE_DEVICES is called before a process is frozen and is used by the CUDA
plugin to place the process in a state that's ready to be checkpointed and
quiesce any pending work

CHECKPOINT_DEVICES is called after all processes in the tree have been frozen
and PAUSE'd and performs the actual checkpointing operation for CUDA
applications

Signed-off-by: Jesus Ramos <[email protected]>

Author: jesus-ramos

criu/include/criu-plugin.h

@@ -56,6 +56,10 @@ enum {
 
 	CR_PLUGIN_HOOK__RESUME_DEVICES_LATE = 9,
 
+	CR_PLUGIN_HOOK__PAUSE_DEVICES = 10,
+
+	CR_PLUGIN_HOOK__CHECKPOINT_DEVICES = 11,
+
 	CR_PLUGIN_HOOK__MAX
 };
 
@@ -72,6 +76,8 @@ DECLARE_PLUGIN_HOOK_ARGS(CR_PLUGIN_HOOK__HANDLE_DEVICE_VMA, int fd, const struct
 DECLARE_PLUGIN_HOOK_ARGS(CR_PLUGIN_HOOK__UPDATE_VMA_MAP, const char *path, const uint64_t addr,
 			 const uint64_t old_pgoff, uint64_t *new_pgoff, int *plugin_fd);
 DECLARE_PLUGIN_HOOK_ARGS(CR_PLUGIN_HOOK__RESUME_DEVICES_LATE, int pid);
+DECLARE_PLUGIN_HOOK_ARGS(CR_PLUGIN_HOOK__PAUSE_DEVICES, int pid);
+DECLARE_PLUGIN_HOOK_ARGS(CR_PLUGIN_HOOK__CHECKPOINT_DEVICES, int pid);
 
 enum {
 	CR_PLUGIN_STAGE__DUMP,

criu/plugin.c

@@ -57,6 +57,8 @@ static cr_plugin_desc_t *cr_gen_plugin_desc(void *h, char *path)
 	__assign_hook(HANDLE_DEVICE_VMA, "cr_plugin_handle_device_vma");
 	__assign_hook(UPDATE_VMA_MAP, "cr_plugin_update_vma_map");
 	__assign_hook(RESUME_DEVICES_LATE, "cr_plugin_resume_devices_late");
+	__assign_hook(PAUSE_DEVICES, "cr_plugin_pause_devices");
+	__assign_hook(CHECKPOINT_DEVICES, "cr_plugin_checkpoint_devices");
 
 #undef __assign_hook
 

criu/seize.c

@@ -16,6 +16,7 @@
 #include "pstree.h"
 #include "criu-log.h"
 #include <compel/ptrace.h>
+#include "plugin.h"
 #include "proc_parse.h"
 #include "seccomp.h"
 #include "seize.h"
@@ -637,6 +638,11 @@ static int collect_children(struct pstree_item *item)
 			goto free;
 		}
 
+		ret = run_plugins(PAUSE_DEVICES, pid);
+		if (ret < 0 && ret != -ENOTSUP) {
+			goto free;
+		}
+
 		if (!opts.freeze_cgroup)
 			/* fails when meets a zombie */
 			__ignore_value(compel_interrupt_task(pid));
@@ -966,6 +972,7 @@ int collect_pstree(void)
 	pid_t pid = root_item->pid->real;
 	int ret = -1;
 	struct proc_status_creds creds;
+	struct pstree_item *iter;
 
 	timing_start(TIME_FREEZING);
 
@@ -984,6 +991,11 @@ int collect_pstree(void)
 	if (opts.freeze_cgroup && freeze_processes())
 		goto err;
 
+	ret = run_plugins(PAUSE_DEVICES, pid);
+	if (ret < 0 && ret != -ENOTSUP) {
+		goto err;
+	}
+
 	if (!opts.freeze_cgroup && compel_interrupt_task(pid)) {
 		set_cr_errno(ESRCH);
 		goto err;
@@ -1017,6 +1029,12 @@ int collect_pstree(void)
 		goto err;
 	}
 
+	for_each_pstree_item(iter) {
+		ret = run_plugins(CHECKPOINT_DEVICES, iter->pid->real);
+		if (ret < 0 && ret != -ENOTSUP)
+			goto err;
+	}
+
 	ret = 0;
 	timing_stop(TIME_FREEZING);
 	timing_start(TIME_FROZEN);