[Qemu-devel] [v4 10/13] migration: Add the core code for decompression

[Liang Li <liang.z.li@intel.com>]

Implement the core logic of multiple thread decompression,
the decompression can work now.

Signed-off-by: Liang Li <liang.z.li@intel.com>
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>
---
 arch_init.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 47 insertions(+), 2 deletions(-)

diff --git a/arch_init.c b/arch_init.c
index 8ef0315..549fdbb 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -814,6 +814,13 @@ static inline void start_compression(CompressParam *param)
     qemu_mutex_unlock(&param->mutex);
 }
 
+static inline void start_decompression(DecompressParam *param)
+{
+    qemu_mutex_lock(&param->mutex);
+    param->busy = true;
+    qemu_cond_signal(&param->cond);
+    qemu_mutex_unlock(&param->mutex);
+}
 
 static uint64_t bytes_transferred;
 
@@ -1347,8 +1354,27 @@ void ram_handle_compressed(void *host, uint8_t ch, uint64_t size)
 
 static void *do_data_decompress(void *opaque)
 {
+    DecompressParam *param = opaque;
+    size_t pagesize;
+
     while (!quit_thread) {
-        /* To be done */
+        qemu_mutex_lock(&param->mutex);
+        while (!param->busy) {
+            qemu_cond_wait(&param->cond, &param->mutex);
+            if (quit_thread) {
+                break;
+            }
+            pagesize = TARGET_PAGE_SIZE;
+            /* uncompress() will return failed in some case, especially
+             * when the page is dirted when doing the compression, it's
+             * not a problem because the dirty page will be retransferred
+             * and uncompress() won't break the data in other pages.
+             */
+            uncompress((Bytef *)param->des, &pagesize,
+                       (const Bytef *)param->compbuf, param->len);
+            param->busy = false;
+        }
+        qemu_mutex_unlock(&param->mutex);
     }
 
     return NULL;
@@ -1379,6 +1405,9 @@ void migrate_decompress_threads_join(void)
     quit_thread = true;
     thread_count = migrate_decompress_threads();
     for (i = 0; i < thread_count; i++) {
+        qemu_cond_signal(&decomp_param[i].cond);
+    }
+    for (i = 0; i < thread_count; i++) {
         qemu_thread_join(decompress_threads + i);
         qemu_mutex_destroy(&decomp_param[i].mutex);
         qemu_cond_destroy(&decomp_param[i].cond);
@@ -1395,7 +1424,23 @@ void migrate_decompress_threads_join(void)
 static void decompress_data_with_multi_threads(uint8_t *compbuf,
                                                void *host, int len)
 {
-    /* To be done */
+    int idx, thread_count;
+
+    thread_count = migrate_decompress_threads();
+    while (true) {
+        for (idx = 0; idx < thread_count; idx++) {
+            if (!decomp_param[idx].busy) {
+                memcpy(decomp_param[idx].compbuf, compbuf, len);
+                decomp_param[idx].des = host;
+                decomp_param[idx].len = len;
+                start_decompression(&decomp_param[idx]);
+                break;
+            }
+        }
+        if (idx < thread_count) {
+            break;
+        }
+    }
 }
 
 static int ram_load(QEMUFile *f, void *opaque, int version_id)
-- 
1.9.1