Re: [Qemu-devel] [PATCH V6 RESEND 7/7] migration/ram: ensure write persistence on loading all data to PMEM.

[Junyan He <junyan.he@hotmail.com>]

Sorry missed dgilbert's comment about RAMBLOCK_FOREACH_MIGRATABLE in previous revision.

________________________________
From: Qemu-devel <qemu-devel-bounces+junyan.he=gmx.com@nongnu.org> on behalf of junyan.he@gmx.com <junyan.he@gmx.com>
Sent: Saturday, June 9, 2018 1:12:31 AM
To: qemu-devel@nongnu.org
Cc: xiaoguangrong.eric@gmail.com; crosthwaite.peter@gmail.com; mst@redhat.com; dgilbert@redhat.com; ehabkost@redhat.com; quintela@redhat.com; Junyan He; stefanha@redhat.com; pbonzini@redhat.com; imammedo@redhat.com; rth@twiddle.net
Subject: [Qemu-devel] [PATCH V6 RESEND 7/7] migration/ram: ensure write persistence on loading all data to PMEM.

From: Junyan He <junyan.he@intel.com>

Because we need to make sure the pmem kind memory data is synced
after migration, we choose to call pmem_persist() when the migration
finish. This will make sure the data of pmem is safe and will not
lose if power is off.

Signed-off-by: Junyan He <junyan.he@intel.com>
---
 include/qemu/pmem.h | 1 +
 migration/ram.c     | 8 ++++++++
 stubs/pmem.c        | 4 ++++
 3 files changed, 13 insertions(+)

diff --git a/include/qemu/pmem.h b/include/qemu/pmem.h
index 00d6680..8f52b08 100644
--- a/include/qemu/pmem.h
+++ b/include/qemu/pmem.h
@@ -17,6 +17,7 @@
 #else  /* !CONFIG_LIBPMEM */

 void *pmem_memcpy_persist(void *pmemdest, const void *src, size_t len);
+void pmem_persist(const void *addr, size_t len);

 #endif /* CONFIG_LIBPMEM */

diff --git a/migration/ram.c b/migration/ram.c
index aa0c6f0..15418c2 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -33,6 +33,7 @@
 #include "qemu/bitops.h"
 #include "qemu/bitmap.h"
 #include "qemu/main-loop.h"
+#include "qemu/pmem.h"
 #include "xbzrle.h"
 #include "ram.h"
 #include "migration.h"
@@ -3046,6 +3047,13 @@ static int ram_load_setup(QEMUFile *f, void *opaque)
 static int ram_load_cleanup(void *opaque)
 {
     RAMBlock *rb;
+
+    RAMBLOCK_FOREACH_MIGRATABLE(rb) {
+        if (ramblock_is_pmem(rb)) {
+            pmem_persist(rb->host, rb->used_length);
+        }
+    }
+
     xbzrle_load_cleanup();
     compress_threads_load_cleanup();

diff --git a/stubs/pmem.c b/stubs/pmem.c
index b4ec72d..f794262 100644
--- a/stubs/pmem.c
+++ b/stubs/pmem.c
@@ -17,3 +17,7 @@ void *pmem_memcpy_persist(void *pmemdest, const void *src, size_t len)
 {
     return memcpy(pmemdest, src, len);
 }
+
+void pmem_persist(const void *addr, size_t len)
+{
+}
--
2.7.4