Re: [PATCH v2 04/13] ram.c: Reset result after sending queued data

[Juan Quintela]

Lukas Straub  wrote:
> And take the param->mutex lock for the whole section to ensure
> thread-safety.
> Now, it is explicitly clear if there is no queued data to send.
> Before, this was handled by param->file stream being empty and thus
> qemu_put_qemu_file() not sending anything.
>
> This will be used in the next commits to move save_page_header()
> out of compress code.
>
> Signed-off-by: Lukas Straub 

Reviewed-by: Juan Quintela 

If you do more changes around here, please consider:

> @@ -1540,13 +1547,16 @@ static void flush_compressed_data(RAMState *rs)
>  for (idx = 0; idx < thread_count; idx++) {

Move

CompressParam *param = &comp_param[idx];

to here, and use it also for the locks.
I will even think about calling the variable just p.

And once there, everything under the sun except this uses i as a for
variable, not idx O:-)

>  qemu_mutex_lock(&comp_param[idx].mutex);
>  if (!comp_param[idx].quit) {
> -len = qemu_put_qemu_file(ms->to_dst_file, comp_param[idx].file);
> +CompressParam *param = &comp_param[idx];

Move this declaration

> +len = qemu_put_qemu_file(ms->to_dst_file, param->file);
> +compress_reset_result(param);
> +
>  /*
>   * it's safe to fetch zero_page without holding comp_done_lock
>   * as there is no further request submitted to the thread,
>   * i.e, the thread should be waiting for a request at this point.
>   */
> -update_compress_thread_counts(&comp_param[idx], len);
> +update_compress_thread_counts(param, len);
>  }
>  qemu_mutex_unlock(&comp_param[idx].mutex);
>  }
> @@ -1571,15 +1581,17 @@ static int compress_page_with_multi_thread(RAMBlock 
> *block, ram_addr_t offset)
>  retry:
>  for (idx = 0; idx < thread_count; idx++) {
>  if (comp_param[idx].done) {
> -comp_param[idx].done = false;


Same here.

[PATCH v2 04/13] ram.c: Reset result after sending queued data

[Lukas Straub]

And take the param->mutex lock for the whole section to ensure
thread-safety.
Now, it is explicitly clear if there is no queued data to send.
Before, this was handled by param->file stream being empty and thus
qemu_put_qemu_file() not sending anything.

This will be used in the next commits to move save_page_header()
out of compress code.

Signed-off-by: Lukas Straub 
---
 migration/ram.c | 32 ++--
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index 820b4ebaeb..5ca0f115cf 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1519,6 +1519,13 @@ update_compress_thread_counts(const CompressParam 
*param, int bytes_xmit)

 static bool save_page_use_compression(RAMState *rs);

+static inline void compress_reset_result(CompressParam *param)
+{
+param->result = RES_NONE;
+param->block = NULL;
+param->offset = 0;
+}
+
 static void flush_compressed_data(RAMState *rs)
 {
 MigrationState *ms = migrate_get_current();
@@ -1540,13 +1547,16 @@ static void flush_compressed_data(RAMState *rs)
 for (idx = 0; idx < thread_count; idx++) {
 qemu_mutex_lock(&comp_param[idx].mutex);
 if (!comp_param[idx].quit) {
-len = qemu_put_qemu_file(ms->to_dst_file, comp_param[idx].file);
+CompressParam *param = &comp_param[idx];
+len = qemu_put_qemu_file(ms->to_dst_file, param->file);
+compress_reset_result(param);
+
 /*
  * it's safe to fetch zero_page without holding comp_done_lock
  * as there is no further request submitted to the thread,
  * i.e, the thread should be waiting for a request at this point.
  */
-update_compress_thread_counts(&comp_param[idx], len);
+update_compress_thread_counts(param, len);
 }
 qemu_mutex_unlock(&comp_param[idx].mutex);
 }
@@ -1571,15 +1581,17 @@ static int compress_page_with_multi_thread(RAMBlock 
*block, ram_addr_t offset)
 retry:
 for (idx = 0; idx < thread_count; idx++) {
 if (comp_param[idx].done) {
-comp_param[idx].done = false;
-bytes_xmit = qemu_put_qemu_file(ms->to_dst_file,
-comp_param[idx].file);
-qemu_mutex_lock(&comp_param[idx].mutex);
-set_compress_params(&comp_param[idx], block, offset);
-qemu_cond_signal(&comp_param[idx].cond);
-qemu_mutex_unlock(&comp_param[idx].mutex);
+CompressParam *param = &comp_param[idx];
+qemu_mutex_lock(¶m->mutex);
+param->done = false;
+bytes_xmit = qemu_put_qemu_file(ms->to_dst_file, param->file);
+compress_reset_result(param);
+set_compress_params(param, block, offset);
+
+update_compress_thread_counts(param, bytes_xmit);
+qemu_cond_signal(¶m->cond);
+qemu_mutex_unlock(¶m->mutex);
 pages = 1;
-update_compress_thread_counts(&comp_param[idx], bytes_xmit);
 break;
 }
 }
--
2.40.0



pgpOdTcrh92DD.pgp
Description: OpenPGP digital signature