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[Qemu-devel] [PATCH REPOST 2/2] dump-guest-memory: add basic "detach" su
From: |
Peter Xu |
Subject: |
[Qemu-devel] [PATCH REPOST 2/2] dump-guest-memory: add basic "detach" support. |
Date: |
Mon, 23 Nov 2015 18:07:42 +0800 |
This will allow the user specify "-d" (just like command
"migrate") when using "dump-guest-memory" command. When
specified, one background thread is created to do the dump work.
One flag is added to show whether there is a background dump
work in progress.
Signed-off-by: Peter Xu <address@hidden>
---
dump.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++-----
include/sysemu/dump.h | 4 ++++
qmp.c | 9 ++++++++
vl.c | 3 +++
4 files changed, 70 insertions(+), 5 deletions(-)
diff --git a/dump.c b/dump.c
index 3ec3423..c2e14cd 100644
--- a/dump.c
+++ b/dump.c
@@ -1442,6 +1442,9 @@ static void dump_init(DumpState *s, int fd, bool
has_format,
Error *err = NULL;
int ret;
+ s->has_format = has_format;
+ s->format = format;
+
/* kdump-compressed is conflict with paging and filter */
if (has_format && format != DUMP_GUEST_MEMORY_FORMAT_ELF) {
assert(!paging && !has_filter);
@@ -1595,6 +1598,45 @@ cleanup:
dump_cleanup(s);
}
+/* whether there is a dump in progress */
+extern bool dump_in_progress_p;
+
+static bool dump_ownership_set(bool value)
+{
+ return atomic_xchg(&dump_in_progress_p, value);
+}
+
+/* return true when owner taken, false otherwise */
+static bool dump_ownership_take(void)
+{
+ bool ret = dump_ownership_set(1);
+ return ret == 0;
+}
+
+/* we should only call this after all dump work finished */
+static void dump_ownership_release(void)
+{
+ dump_ownership_set(0);
+}
+
+static void dump_process(DumpState *s, Error **errp)
+{
+ if (s->has_format && s->format != DUMP_GUEST_MEMORY_FORMAT_ELF) {
+ create_kdump_vmcore(s, errp);
+ } else {
+ create_vmcore(s, errp);
+ }
+ dump_ownership_release();
+}
+
+static void *dump_thread(void *data)
+{
+ DumpState *s = (DumpState *)data;
+ dump_process(s, NULL);
+ g_free(s);
+ return NULL;
+}
+
void qmp_dump_guest_memory(bool paging, const char *file, bool has_begin,
int64_t begin, bool has_length,
int64_t length, bool has_format,
@@ -1662,6 +1704,12 @@ void qmp_dump_guest_memory(bool paging, const char
*file, bool has_begin,
return;
}
+ /* we could only allow one dump at a time. */
+ if (!dump_ownership_take()) {
+ error_setg(errp, "another dump is in progress.");
+ return;
+ }
+
s = g_malloc0(sizeof(DumpState));
dump_init(s, fd, has_format, format, paging, has_begin,
@@ -1672,13 +1720,14 @@ void qmp_dump_guest_memory(bool paging, const char
*file, bool has_begin,
return;
}
- if (has_format && format != DUMP_GUEST_MEMORY_FORMAT_ELF) {
- create_kdump_vmcore(s, errp);
+ if (!detach) {
+ dump_process(s, errp);
+ g_free(s);
} else {
- create_vmcore(s, errp);
+ qemu_thread_create(&s->dump_thread, "dump_thread", dump_thread,
+ s, QEMU_THREAD_DETACHED);
+ /* DumpState is freed in dump thread */
}
-
- g_free(s);
}
DumpGuestMemoryCapability *qmp_query_dump_guest_memory_capability(Error **errp)
diff --git a/include/sysemu/dump.h b/include/sysemu/dump.h
index 7e4ec5c..2aeffc8 100644
--- a/include/sysemu/dump.h
+++ b/include/sysemu/dump.h
@@ -183,6 +183,10 @@ typedef struct DumpState {
off_t offset_page; /* offset of page part in vmcore */
size_t num_dumpable; /* number of page that can be dumped */
uint32_t flag_compress; /* indicate the compression format */
+
+ QemuThread dump_thread; /* only used when do async dump */
+ bool has_format; /* whether format is provided */
+ DumpGuestMemoryFormat format; /* valid only if has_format == true */
} DumpState;
uint16_t cpu_to_dump16(DumpState *s, uint16_t val);
diff --git a/qmp.c b/qmp.c
index 0a1fa19..ea57b57 100644
--- a/qmp.c
+++ b/qmp.c
@@ -168,12 +168,21 @@ SpiceInfo *qmp_query_spice(Error **errp)
};
#endif
+extern bool dump_in_progress_p;
+
void qmp_cont(Error **errp)
{
Error *local_err = NULL;
BlockBackend *blk;
BlockDriverState *bs;
+ /* if there is a dump in background, we should wait until the dump
+ * finished */
+ if (dump_in_progress_p) {
+ error_setg(errp, "there is a dump in process, please wait.");
+ return;
+ }
+
if (runstate_needs_reset()) {
error_setg(errp, "Resetting the Virtual Machine is required");
return;
diff --git a/vl.c b/vl.c
index 525929b..ef7a936 100644
--- a/vl.c
+++ b/vl.c
@@ -204,6 +204,9 @@ bool xen_allowed;
uint32_t xen_domid;
enum xen_mode xen_mode = XEN_EMULATE;
+/* whether dump is in progress */
+bool dump_in_progress_p = false;
+
static int has_defaults = 1;
static int default_serial = 1;
static int default_parallel = 1;
--
2.4.3