criu: raise the task file limit for specific commands

We don't need to do this from early_init.

Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>

criu/cr-dump.c

@@ -1557,6 +1557,11 @@ int cr_pre_dump_tasks(pid_t pid)
 	struct pstree_item *item;
 	int ret = -1;
 
+	/*
+	 * We might need a lot of pipes to fetch huge number of pages to dump.
+	 */
+	rlimit_unlimit_nofile();
+
 	root_item = alloc_pstree_item();
 	if (!root_item)
 		goto err;
@@ -1754,6 +1759,13 @@ int cr_dump_tasks(pid_t pid)
 	pr_info("Dumping processes (pid: %d)\n", pid);
 	pr_info("========================================\n");
 
+	/*
+	 *  We will fetch all file descriptors for each task, their number can
+	 *  be bigger than a default file limit, so we need to raise it to the
+	 *  maximum.
+	 */
+	rlimit_unlimit_nofile();
+
 	root_item = alloc_pstree_item();
 	if (!root_item)
 		goto err;

criu/cr-restore.c

@@ -2330,6 +2330,9 @@ int cr_restore_tasks(void)
 {
 	int ret = -1;
 
+	if (init_service_fd())
+		return 1;
+
 	if (cr_plugin_init(CR_PLUGIN_STAGE__RESTORE))
 		return -1;
 

criu/crtools.c

@@ -20,9 +20,6 @@
 
 #include <sys/utsname.h>
 
-#include <sys/time.h>
-#include <sys/resource.h>
-
 #include "int.h"
 #include "page.h"
 #include "common/compiler.h"
@@ -50,79 +47,6 @@
 #include "setproctitle.h"
 #include "sysctl.h"
 
-static void rlimit_unlimit_nofile(void)
-{
-	struct rlimit new;
-
-	new.rlim_cur = kdat.sysctl_nr_open;
-	new.rlim_max = kdat.sysctl_nr_open;
-
-	if (prlimit(getpid(), RLIMIT_NOFILE, &new, NULL)) {
-		pr_perror("rlimit: Can't setup RLIMIT_NOFILE for self");
-		return;
-	} else
-		pr_debug("rlimit: RLIMIT_NOFILE unlimited for self\n");
-
-	service_fd_rlim_cur = kdat.sysctl_nr_open;
-}
-
-static int early_init(const char *cmd)
-{
-	static const char *nofile_cmds[] = {
-		"swrk", "service",
-		"dump", "pre-dump",
-		"restore",
-	};
-	size_t i;
-
-	/*
-	 * Service fd engine implies that file descriptors
-	 * used won't be borrowed by the rest of the code
-	 * and default 1024 limit is not enough for high
-	 * loaded test/containers. Thus use kdat engine
-	 * to fetch current system level limit for numbers
-	 * of files allowed to open up and lift up own
-	 * limits.
-	 *
-	 * Note we have to do it before the service fd
-	 * get inited and we dont exit with errors here
-	 * because in worst scenario where clash of fd
-	 * happen we simply exit with explicit error
-	 * during real action stage.
-	 *
-	 * Same time raising limits cause kernel fdtable
-	 * to bloat so we do this only on the @nofile_cmds:
-	 *
-	 *  - on dump criu needs additional files for sfd,
-	 *    thus if container already has many files opened
-	 *    we need to have at least not less space when
-	 *    fetching fds from a target process;
-	 *
-	 *  - on pre-dump we might need a lot of pipes to
-	 *    fetch huge number of pages to dump;
-	 *
-	 *  - on restore we still need to raise limits since
-	 *    there is no guarantee that on dump we've not
-	 *    been hitting fd limit already;
-	 *
-	 *  - swrk and service obtain requests on the fly,
-	 *    thus we don't know if on of above will be
-	 *    there thus raise limits.
-	 */
-	for (i = 0; i < ARRAY_SIZE(nofile_cmds); i++) {
-		if (strcmp(nofile_cmds[i], cmd))
-			continue;
-		if (!kerndat_files_stat(true))
-			rlimit_unlimit_nofile();
-		break;
-	}
-
-	if (init_service_fd())
-		return 1;
-
-	return 0;
-}
-
 int main(int argc, char *argv[], char *envp[])
 {
 	int ret = -1;
@@ -158,9 +82,6 @@ int main(int argc, char *argv[], char *envp[])
 
 	log_set_loglevel(opts.log_level);
 
-	if (early_init(argv[optind]))
-		return -1;
-
 	if (!strcmp(argv[1], "swrk")) {
 		if (argc < 3)
 			goto usage;

criu/include/util.h

@@ -350,6 +350,8 @@ extern int epoll_del_rfd(int epfd, struct epoll_rfd *rfd);
 extern int epoll_run_rfds(int epfd, struct epoll_event *evs, int nr_fds, int tmo);
 extern int epoll_prepare(int nr_events, struct epoll_event **evs);
 
+extern void rlimit_unlimit_nofile(void);
+
 extern int call_in_child_process(int (*fn)(void *), void *arg);
 #ifdef __GLIBC__
 extern void print_stack_trace(pid_t pid);

criu/servicefd.c

@@ -67,6 +67,20 @@ int init_service_fd(void)
 {
 	struct rlimit64 rlimit;
 
+	/*
+	 * Service fd engine implies that file descriptors used won't be
+	 * borrowed by the rest of the code and default 1024 limit is not
+	 * enough for high loaded test/containers. Thus use kdat engine to
+	 * fetch current system level limit for numbers of files allowed to
+	 * open up and lift up own limits.
+	 *
+	 * Note we have to do it before the service fd get initialized and we
+	 * don't exit with errors here because in worst scenario where clash of
+	 * fd happen we simply exit with explicit error during real action
+	 * stage.
+	 */
+	rlimit_unlimit_nofile();
+
 	/*
 	 * Service FDs are those that most likely won't
 	 * conflict with any 'real-life' ones

criu/util.c

@@ -20,12 +20,15 @@
 #include <sys/mman.h>
 #include <sys/wait.h>
 #include <sys/socket.h>
+#include <sys/time.h>
+#include <sys/resource.h>
 #include <netdb.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
 #include <sched.h>
 #include <ctype.h>
 
+#include "kerndat.h"
 #include "page.h"
 #include "util.h"
 #include "image.h"
@@ -1348,6 +1351,23 @@ out:
 	return ret;
 }
 
+void rlimit_unlimit_nofile(void)
+{
+	struct rlimit new;
+
+	new.rlim_cur = kdat.sysctl_nr_open;
+	new.rlim_max = kdat.sysctl_nr_open;
+
+	if (prlimit(getpid(), RLIMIT_NOFILE, &new, NULL)) {
+		pr_perror("rlimit: Can't setup RLIMIT_NOFILE for self");
+		return;
+	} else
+		pr_debug("rlimit: RLIMIT_NOFILE unlimited for self\n");
+
+	service_fd_rlim_cur = kdat.sysctl_nr_open;
+}
+
+
 #ifdef __GLIBC__
 #include <execinfo.h>
 void print_stack_trace(pid_t pid)