[CRIU] [PATCH 1/7] Adding --pre-dump-mode option
Abhishek Dubey
dubeyabhishek777 at gmail.com
Sun Aug 25 04:58:15 MSK 2019
There exists two modes of pre-dump algorithm:
1) splicing memory by parasite
--pre-dump-mode=splice (default)
2) using process_vm_readv syscall
--pre-dump-mode=read
Signed-off-by: Abhishek Dubey <dubeyabhishek777 at gmail.com>
---
Documentation/criu.txt | 6 ++++++
criu/config.c | 10 ++++++++++
criu/cr-dump.c | 6 +++++-
criu/crtools.c | 2 ++
criu/include/cr_options.h | 7 +++++++
criu/mem.c | 13 ++++++++++++-
test/zdtm.py | 9 ++++++++-
7 files changed, 50 insertions(+), 3 deletions(-)
diff --git a/Documentation/criu.txt b/Documentation/criu.txt
index 94fc542..674967f 100644
--- a/Documentation/criu.txt
+++ b/Documentation/criu.txt
@@ -156,6 +156,12 @@ In addition, *page-server* options may be specified.
Turn on memory changes tracker in the kernel. If the option is
not passed the memory tracker get turned on implicitly.
+*--pre-dump-mode*='mode'::
+ There are two 'mode' to operate pre-dump algorithm. The 'splice' mode
+ is parasite based, whereas 'read' mode is based on process_vm_readv
+ syscall. The 'read' mode incurs reduced frozen time and reduced
+ memory pressure as compared to 'splice' mode. Default is 'splice' mode.
+
*dump*
~~~~~~
Performs a checkpoint procedure.
diff --git a/criu/config.c b/criu/config.c
index 3a54afd..3c65dc0 100644
--- a/criu/config.c
+++ b/criu/config.c
@@ -276,6 +276,7 @@ void init_opts(void)
opts.empty_ns = 0;
opts.status_fd = -1;
opts.log_level = DEFAULT_LOGLEVEL;
+ opts.pre_dump_mode = PRE_DUMP_SPLICE;
}
bool deprecated_ok(char *what)
@@ -517,6 +518,7 @@ int parse_options(int argc, char **argv, bool *usage_error,
{ "tls-key", required_argument, 0, 1095},
BOOL_OPT("tls", &opts.tls),
{"tls-no-cn-verify", no_argument, &opts.tls_no_cn_verify, true},
+ { "pre-dump-mode", required_argument, 0, 1097},
{ },
};
@@ -815,6 +817,14 @@ int parse_options(int argc, char **argv, bool *usage_error,
case 1095:
SET_CHAR_OPTS(tls_key, optarg);
break;
+ case 1097:
+ if (!strcmp("read", optarg)) {
+ opts.pre_dump_mode = PRE_DUMP_READ;
+ } else if (strcmp("splice", optarg)) {
+ pr_err("Unable to parse value of --pre-dump-mode\n");
+ return 1;
+ }
+ break;
case 'V':
pr_msg("Version: %s\n", CRIU_VERSION);
if (strcmp(CRIU_GITID, "0"))
diff --git a/criu/cr-dump.c b/criu/cr-dump.c
index e070b8b..a7ce1ce 100644
--- a/criu/cr-dump.c
+++ b/criu/cr-dump.c
@@ -1513,7 +1513,11 @@ static int cr_pre_dump_finish(int status)
goto err;
mem_pp = dmpi(item)->mem_pp;
- ret = page_xfer_dump_pages(&xfer, mem_pp);
+
+ if (opts.pre_dump_mode == PRE_DUMP_READ)
+ ret = 0; /* Call optimized pre-dump here */
+ else
+ ret = page_xfer_dump_pages(&xfer, mem_pp);
xfer.close(&xfer);
diff --git a/criu/crtools.c b/criu/crtools.c
index 97a6d6d..fc17d83 100644
--- a/criu/crtools.c
+++ b/criu/crtools.c
@@ -442,6 +442,8 @@ usage:
" pages images of previous dump\n"
" when used on restore, as soon as page is restored, it\n"
" will be punched from the image\n"
+" --pre-dump-mode splice - parasite based pre-dumping (default)\n"
+" read - process_vm_readv syscall based pre-dumping\n"
"\n"
"Page/Service server options:\n"
" --address ADDR address of server or service\n"
diff --git a/criu/include/cr_options.h b/criu/include/cr_options.h
index c519c74..e50989f 100644
--- a/criu/include/cr_options.h
+++ b/criu/include/cr_options.h
@@ -39,6 +39,12 @@ struct cg_root_opt {
};
/*
+ * Pre-dump variants
+ */
+#define PRE_DUMP_SPLICE 1 /* Pre-dump using parasite */
+#define PRE_DUMP_READ 2 /* Pre-dump using process_vm_readv syscall */
+
+/*
* Cgroup management options.
*/
#define CG_MODE_IGNORE (0u << 0) /* Zero is important here */
@@ -81,6 +87,7 @@ struct cr_options {
int evasive_devices;
int link_remap_ok;
int log_file_per_pid;
+ int pre_dump_mode;
bool swrk_restore;
char *output;
char *root;
diff --git a/criu/mem.c b/criu/mem.c
index de66a62..911b9d2 100644
--- a/criu/mem.c
+++ b/criu/mem.c
@@ -482,7 +482,18 @@ static int __parasite_dump_pages_seized(struct pstree_item *item,
if (mdc->lazy)
memcpy(pargs_iovs(args), pp->iovs,
sizeof(struct iovec) * pp->nr_iovs);
- ret = drain_pages(pp, ctl, args);
+
+ /*
+ * Faking drain_pages for pre-dump here. Actual drain_pages for pre-dump
+ * will happen after task unfreezing in cr_pre_dump_finish(). This is
+ * actual optimization which reduces time for which process was frozen
+ * during pre-dump.
+ */
+ if (mdc->pre_dump && opts.pre_dump_mode == PRE_DUMP_READ)
+ ret = 0;
+ else
+ ret = drain_pages(pp, ctl, args);
+
if (!ret && !mdc->pre_dump)
ret = xfer_pages(pp, &xfer);
if (ret)
diff --git a/test/zdtm.py b/test/zdtm.py
index 9b93a51..ca8b165 100755
--- a/test/zdtm.py
+++ b/test/zdtm.py
@@ -1020,6 +1020,7 @@ class criu:
self.__tls = self.__tls_options() if opts['tls'] else []
self.__criu_bin = opts['criu_bin']
self.__crit_bin = opts['crit_bin']
+ self.__pre_dump_mode = opts['pre_dump_mode']
def fini(self):
if self.__lazy_migrate:
@@ -1276,6 +1277,8 @@ class criu:
a_opts += ['--leave-stopped']
if self.__empty_ns:
a_opts += ['--empty-ns', 'net']
+ if self.__pre_dump_mode:
+ a_opts += ["--pre-dump-mode", "%s" % self.__pre_dump_mode]
nowait = False
if self.__lazy_migrate and action == "dump":
@@ -1865,7 +1868,7 @@ class Launcher:
'sat', 'script', 'rpc', 'lazy_pages', 'join_ns', 'dedup', 'sbs',
'freezecg', 'user', 'dry_run', 'noauto_dedup',
'remote_lazy_pages', 'show_stats', 'lazy_migrate', 'remote',
- 'tls', 'criu_bin', 'crit_bin')
+ 'tls', 'criu_bin', 'crit_bin', 'pre_dump_mode')
arg = repr((name, desc, flavor, {d: self.__opts[d] for d in nd}))
if self.__use_log:
@@ -2512,6 +2515,10 @@ rp.add_argument("--criu-bin",
rp.add_argument("--crit-bin",
help="Path to crit binary",
default='../crit/crit')
+rp.add_argument("--pre-dump-mode",
+ help="Use splice or read mode of pre-dumping",
+ choices=['splice', 'read'],
+ default='splice')
lp = sp.add_parser("list", help="List tests")
lp.set_defaults(action=list_tests)
--
2.7.4
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