save_page_header() accesses several global variables, so calling it
from multiple threads is pretty ugly.
Instead, call save_page_header() before writing out the compressed
data from the compress buffer to the migration stream.
This also makes the core compress code more independend from ram.c.
Signed-off-by: Lukas Straub
---
migration/ram.c | 44 +++-
1 file changed, 35 insertions(+), 9 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index 5ca0f115cf..d248e1f062 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1476,17 +1476,13 @@ static CompressResult do_compress_ram_page(QEMUFile *f,
z_stream *stream,
RAMBlock *block, ram_addr_t offset,
uint8_t *source_buf)
{
-RAMState *rs = ram_state;
-PageSearchStatus *pss = >pss[RAM_CHANNEL_PRECOPY];
uint8_t *p = block->host + offset;
int ret;
-if (save_zero_page_to_file(pss, f, block, offset)) {
+if (buffer_is_zero(p, TARGET_PAGE_SIZE)) {
return RES_ZEROPAGE;
}
-save_page_header(pss, f, block, offset | RAM_SAVE_FLAG_COMPRESS_PAGE);
-
/*
* copy it to a internal buffer to avoid it being modified by VM
* so that we can catch up the error during compression and
@@ -1526,9 +1522,40 @@ static inline void compress_reset_result(CompressParam
*param)
param->offset = 0;
}
-static void flush_compressed_data(RAMState *rs)
+static int send_queued_data(CompressParam *param)
{
+PageSearchStatus *pss = _state->pss[RAM_CHANNEL_PRECOPY];
MigrationState *ms = migrate_get_current();
+QEMUFile *file = ms->to_dst_file;
+int len = 0;
+
+RAMBlock *block = param->block;
+ram_addr_t offset = param->offset;
+
+if (param->result == RES_NONE) {
+return 0;
+}
+
+assert(block == pss->last_sent_block);
+
+if (param->result == RES_ZEROPAGE) {
+len += save_page_header(pss, file, block, offset | RAM_SAVE_FLAG_ZERO);
+qemu_put_byte(file, 0);
+len += 1;
+ram_release_page(block->idstr, offset);
+} else if (param->result == RES_COMPRESS) {
+len += save_page_header(pss, file, block,
+offset | RAM_SAVE_FLAG_COMPRESS_PAGE);
+len += qemu_put_qemu_file(file, param->file);
+} else {
+abort();
+}
+
+return len;
+}
+
+static void flush_compressed_data(RAMState *rs)
+{
int idx, len, thread_count;
if (!save_page_use_compression(rs)) {
@@ -1548,7 +1575,7 @@ static void flush_compressed_data(RAMState *rs)
qemu_mutex_lock(_param[idx].mutex);
if (!comp_param[idx].quit) {
CompressParam *param = _param[idx];
-len = qemu_put_qemu_file(ms->to_dst_file, param->file);
+len = send_queued_data(param);
compress_reset_result(param);
/*
@@ -1574,7 +1601,6 @@ static int compress_page_with_multi_thread(RAMBlock
*block, ram_addr_t offset)
{
int idx, thread_count, bytes_xmit = -1, pages = -1;
bool wait = migrate_compress_wait_thread();
-MigrationState *ms = migrate_get_current();
thread_count = migrate_compress_threads();
qemu_mutex_lock(_done_lock);
@@ -1584,7 +1610,7 @@ retry:
CompressParam *param = _param[idx];
qemu_mutex_lock(>mutex);
param->done = false;
-bytes_xmit = qemu_put_qemu_file(ms->to_dst_file, param->file);
+bytes_xmit = send_queued_data(param);
compress_reset_result(param);
set_compress_params(param, block, offset);
--
2.40.0
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