Re: [Qemu-devel] [PATCH 47/51] ram: Change offset field in PageSearchStatus to page

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Juan Quintela (quintela@redhat.com) wrote:
> We are moving everything to work on pages, not addresses.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  migration/ram.c | 50 +++++++++++++++++++++++++-------------------------
>  1 file changed, 25 insertions(+), 25 deletions(-)
> 
> diff --git a/migration/ram.c b/migration/ram.c
> index 57b776b..ef3b428 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -298,8 +298,8 @@ uint64_t ram_postcopy_requests(void)
>  struct PageSearchStatus {
>      /* Current block being searched */
>      RAMBlock    *block;
> -    /* Current offset to search from */
> -    ram_addr_t   offset;
> +    /* Current page to search from */
> +    unsigned long page;
>      /* Set once we wrap around */
>      bool         complete_round;
>  };
> @@ -610,16 +610,16 @@ static int save_xbzrle_page(RAMState *rs, uint8_t **current_data,
>   *
>   * @rs: current RAM state
>   * @rb: RAMBlock where to search for dirty pages
> - * @start: starting address (typically so we can continue from previous page)
> + * @start: page where we start the search
>   * @page: pointer into where to store the dirty page
>   */
>  static inline
> -ram_addr_t migration_bitmap_find_dirty(RAMState *rs, RAMBlock *rb,
> -                                       ram_addr_t start,
> -                                       unsigned long *page)
> +unsigned long migration_bitmap_find_dirty(RAMState *rs, RAMBlock *rb,
> +                                          unsigned long start,
> +                                          unsigned long *page)
>  {
>      unsigned long base = rb->offset >> TARGET_PAGE_BITS;
> -    unsigned long nr = base + (start >> TARGET_PAGE_BITS);
> +    unsigned long nr = base + start;
>      uint64_t rb_size = rb->used_length;
>      unsigned long size = base + (rb_size >> TARGET_PAGE_BITS);
>      unsigned long *bitmap;
> @@ -634,7 +634,7 @@ ram_addr_t migration_bitmap_find_dirty(RAMState *rs, RAMBlock *rb,
>      }
>  
>      *page = next;
> -    return (next - base) << TARGET_PAGE_BITS;
> +    return next - base;
>  }
>  
>  static inline bool migration_bitmap_clear_dirty(RAMState *rs,
> @@ -812,7 +812,7 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss, bool last_stage)
>      int ret;
>      bool send_async = true;
>      RAMBlock *block = pss->block;
> -    ram_addr_t offset = pss->offset;
> +    ram_addr_t offset = pss->page << TARGET_PAGE_BITS;
>  
>      p = block->host + offset;
>  
> @@ -844,7 +844,7 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss, bool last_stage)
>               * page would be stale
>               */
>              xbzrle_cache_zero_page(rs, current_addr);
> -            ram_release_pages(block->idstr, pss->offset, pages);
> +            ram_release_pages(block->idstr, offset, pages);
>          } else if (!rs->ram_bulk_stage &&
>                     !migration_in_postcopy() && migrate_use_xbzrle()) {
>              pages = save_xbzrle_page(rs, &p, current_addr, block,
> @@ -987,7 +987,7 @@ static int ram_save_compressed_page(RAMState *rs, PageSearchStatus *pss,
>      uint8_t *p;
>      int ret, blen;
>      RAMBlock *block = pss->block;
> -    ram_addr_t offset = pss->offset;
> +    ram_addr_t offset = pss->page << TARGET_PAGE_BITS;
>  
>      p = block->host + offset;
>  
> @@ -1031,14 +1031,14 @@ static int ram_save_compressed_page(RAMState *rs, PageSearchStatus *pss,
>                  }
>              }
>              if (pages > 0) {
> -                ram_release_pages(block->idstr, pss->offset, pages);
> +                ram_release_pages(block->idstr, offset, pages);
>              }
>          } else {
>              pages = save_zero_page(rs, block, offset, p);
>              if (pages == -1) {
>                  pages = compress_page_with_multi_thread(rs, block, offset);
>              } else {
> -                ram_release_pages(block->idstr, pss->offset, pages);
> +                ram_release_pages(block->idstr, offset, pages);
>              }
>          }
>      }
> @@ -1060,10 +1060,9 @@ static int ram_save_compressed_page(RAMState *rs, PageSearchStatus *pss,
>  static bool find_dirty_block(RAMState *rs, PageSearchStatus *pss,
>                               bool *again, unsigned long *page)
>  {
> -    pss->offset = migration_bitmap_find_dirty(rs, pss->block, pss->offset,
> -                                              page);
> +    pss->page = migration_bitmap_find_dirty(rs, pss->block, pss->page, page);
>      if (pss->complete_round && pss->block == rs->last_seen_block &&
> -        pss->offset >= rs->last_page) {
> +        pss->page >= rs->last_page) {
>          /*
>           * We've been once around the RAM and haven't found anything.
>           * Give up.
> @@ -1071,9 +1070,9 @@ static bool find_dirty_block(RAMState *rs, PageSearchStatus *pss,
>          *again = false;
>          return false;
>      }
> -    if (pss->offset >= pss->block->used_length) {
> +    if ((pss->page << TARGET_PAGE_BITS) >= pss->block->used_length) {
>          /* Didn't find anything in this RAM Block */
> -        pss->offset = 0;
> +        pss->page = 0;
>          pss->block = QLIST_NEXT_RCU(pss->block, next);
>          if (!pss->block) {
>              /* Hit the end of the list */
> @@ -1196,7 +1195,7 @@ static bool get_queued_page(RAMState *rs, PageSearchStatus *pss,
>           * it just requested.
>           */
>          pss->block = block;
> -        pss->offset = offset;
> +        pss->page = offset >> TARGET_PAGE_BITS;
>      }
>  
>      return !!block;
> @@ -1351,7 +1350,8 @@ static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss,
>                                unsigned long page)
>  {
>      int tmppages, pages = 0;
> -    size_t pagesize = qemu_ram_pagesize(pss->block);
> +    size_t pagesize_bits =
> +        qemu_ram_pagesize(pss->block) >> TARGET_PAGE_BITS;
>  
>      do {
>          tmppages = ram_save_target_page(rs, pss, last_stage, page);
> @@ -1360,12 +1360,12 @@ static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss,
>          }
>  
>          pages += tmppages;
> -        pss->offset += TARGET_PAGE_SIZE;
> +        pss->page++;
>          page++;
> -    } while (pss->offset & (pagesize - 1));
> +    } while (pss->page & (pagesize_bits - 1));
>  
>      /* The offset we leave with is the last one we looked at */
> -    pss->offset -= TARGET_PAGE_SIZE;
> +    pss->page--;
>      return pages;
>  }
>  
> @@ -1396,7 +1396,7 @@ static int ram_find_and_save_block(RAMState *rs, bool last_stage)
>      }
>  
>      pss.block = rs->last_seen_block;
> -    pss.offset = rs->last_page << TARGET_PAGE_BITS;
> +    pss.page = rs->last_page;
>      pss.complete_round = false;
>  
>      if (!pss.block) {
> @@ -1418,7 +1418,7 @@ static int ram_find_and_save_block(RAMState *rs, bool last_stage)
>      } while (!pages && again);
>  
>      rs->last_seen_block = pss.block;
> -    rs->last_page = pss.offset >> TARGET_PAGE_BITS;
> +    rs->last_page = pss.page;
>  
>      return pages;
>  }
> -- 
> 2.9.3
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK