[CRIU] [PATCH] criu: raise the task file limit for specific commands

[Andrei Vagin]

We don't need to do this from early_init.

Cc: Cyrill Gorcunov <gorcunov at gmail.com>
Signed-off-by: Andrei Vagin <avagin at gmail.com>
---
 criu/cr-dump.c    | 11 +++++++++++
 criu/cr-restore.c | 11 +++++++++++
 criu/crtools.c    | 49 -------------------------------------------------
 3 files changed, 22 insertions(+), 49 deletions(-)

diff --git a/criu/cr-dump.c b/criu/cr-dump.c
index d4ed40b91..001dd2a6e 100644
--- a/criu/cr-dump.c
+++ b/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 +1759,12 @@ int cr_dump_tasks(pid_t pid)
 	pr_info("Dumping processes (pid: %d)\n", pid);
 	pr_info("========================================\n");
 
+	/*
+	 * CRIU will fetch all file descriptors for each task. A task can have
+	 * many opened files, so we need to raise a file limit.
+	 */
+	rlimit_unlimit_nofile();
+
 	root_item = alloc_pstree_item();
 	if (!root_item)
 		goto err;
diff --git a/criu/cr-restore.c b/criu/cr-restore.c
index 6a3d62450..c313abf19 100644
--- a/criu/cr-restore.c
+++ b/criu/cr-restore.c
@@ -2330,6 +2330,17 @@ int cr_restore_tasks(void)
 {
 	int ret = -1;
 
+	/*
+	 * 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.
+	 */
+	rlimit_unlimit_nofile();
+
 	if (cr_plugin_init(CR_PLUGIN_STAGE__RESTORE))
 		return -1;
 
diff --git a/criu/crtools.c b/criu/crtools.c
index 6a2955287..883a50317 100644
--- a/criu/crtools.c
+++ b/criu/crtools.c
@@ -68,55 +68,6 @@ static void rlimit_unlimit_nofile(void)
 
 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;
 
-- 
2.14.5