[Qemu-devel] [PATCH v2 3/8] rdma: export ram_handle_compressed()

[mrhines]

From: "Michael R. Hines" <address@hidden>

This gives RDMA shared access to madvise() on the destination side
when an entire chunk is found to be zero.

Signed-off-by: Michael R. Hines <address@hidden>
---
 arch_init.c                   |   24 ++++++++++++++++--------
 include/migration/migration.h |    1 +
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/arch_init.c b/arch_init.c
index 769ce77..77b485c 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -770,6 +770,21 @@ static inline void *host_from_stream_offset(QEMUFile *f,
     return NULL;
 }
 
+/*
+ * If a page (or a whole RDMA chunk) has been
+ * determined to be zero, then zap it.
+ */
+void ram_handle_compressed(void *host, uint8_t ch, uint64_t size)
+{
+    memset(host, ch, TARGET_PAGE_SIZE);
+#ifndef _WIN32
+    if (ch == 0 && (!kvm_enabled() || kvm_has_sync_mmu()) &&
+                            getpagesize() <= TARGET_PAGE_SIZE) {
+        qemu_madvise(host, size, QEMU_MADV_DONTNEED);
+    }
+#endif
+}
+
 static int ram_load(QEMUFile *f, void *opaque, int version_id)
 {
     ram_addr_t addr;
@@ -837,14 +852,7 @@ static int ram_load(QEMUFile *f, void *opaque, int 
version_id)
             }
 
             ch = qemu_get_byte(f);
-            memset(host, ch, TARGET_PAGE_SIZE);
-#ifndef _WIN32
-            if (ch == 0 &&
-                (!kvm_enabled() || kvm_has_sync_mmu()) &&
-                getpagesize() <= TARGET_PAGE_SIZE) {
-                qemu_madvise(host, TARGET_PAGE_SIZE, QEMU_MADV_DONTNEED);
-            }
-#endif
+            ram_handle_compressed(host, ch, TARGET_PAGE_SIZE);
         } else if (flags & RAM_SAVE_FLAG_PAGE) {
             void *host;
 
diff --git a/include/migration/migration.h b/include/migration/migration.h
index f6df8d1..0f4510f 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -143,4 +143,5 @@ void ram_control_load_hook(QEMUFile *f, uint32_t flags);
 size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
                              ram_addr_t offset, size_t size);
 
+void ram_handle_compressed(void *host, uint8_t ch, uint64_t size);
 #endif
-- 
1.7.10.4