Re: [Qemu-devel] [v6 10/14] migration: Add the core code for decompression

[Juan Quintela]

Liang Li <address@hidden> wrote:
> Implement the core logic of multiple thread decompression,
> the decompression can work now.
>
> Signed-off-by: Liang Li <address@hidden>
> Signed-off-by: Yang Zhang <address@hidden>
> ---
>  arch_init.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 48 insertions(+), 2 deletions(-)
>
> diff --git a/arch_init.c b/arch_init.c
> index b81acc9..6a0d709 100644
> --- a/arch_init.c
> +++ b/arch_init.c
> @@ -888,6 +888,13 @@ 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->start = true;

start protucetd by param->mutex

> +    qemu_cond_signal(&param->cond);
> +    qemu_mutex_unlock(&param->mutex);
> +}
>  
>  static uint64_t bytes_transferred;
>  
> @@ -1459,8 +1466,26 @@ 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_decomp_thread) {

quit_decomp_thread locking (or lack of it is equivalent to the one of 
quit_comp_thread)



> -        /* To be done */
> +        qemu_mutex_lock(&param->mutex);
> +        while (!param->start && !quit_decomp_thread) {

start protected by param->mutex.


> +            qemu_cond_wait(&param->cond, &param->mutex);
> +            pagesize = TARGET_PAGE_SIZE;
> +            if (!quit_decomp_thread) {
> +                /* 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->start = false;
> +        }
> +        qemu_mutex_unlock(&param->mutex);
>      }
>  
>      return NULL;
> @@ -1492,6 +1517,11 @@ void migrate_decompress_threads_join(void)
>      quit_decomp_thread = true;
>      thread_count = migrate_decompress_threads();
>      for (i = 0; i < thread_count; i++) {
> +        qemu_mutex_lock(&decomp_param[i].mutex);
> +        qemu_cond_signal(&decomp_param[i].cond);
> +        qemu_mutex_unlock(&decomp_param[i].mutex);
> +    }
> +    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);
> @@ -1508,7 +1538,23 @@ 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].start) {

start not protected

> +                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)