* Orit Wasserman (owass...@redhat.com) wrote:
> It is better to fail migration in case of failure to
> allocate new cache item
Does this actually fail migration or just drop back to sending an uncompressed
page? (I think the latter, and that's an even better result).
> Signed-off-by: Orit Wasserman <owass...@redhat.com>
> ---
> arch_init.c | 4 +++-
> include/migration/page_cache.h | 4 +++-
> page_cache.c | 16 +++++++++++-----
> 3 files changed, 17 insertions(+), 7 deletions(-)
>
> diff --git a/arch_init.c b/arch_init.c
> index 806d096..0bfbc5a 100644
> --- a/arch_init.c
> +++ b/arch_init.c
> @@ -284,7 +284,9 @@ static int save_xbzrle_page(QEMUFile *f, uint8_t
> *current_data,
>
> if (!cache_is_cached(XBZRLE.cache, current_addr)) {
> if (!last_stage) {
> - cache_insert(XBZRLE.cache, current_addr, current_data);
> + if (cache_insert(XBZRLE.cache, current_addr, current_data) ==
> -1) {
> + return -1;
> + }
> }
> acct_info.xbzrle_cache_miss++;
> return -1;
> diff --git a/include/migration/page_cache.h b/include/migration/page_cache.h
> index 87894fe..d156f0d 100644
> --- a/include/migration/page_cache.h
> +++ b/include/migration/page_cache.h
> @@ -60,11 +60,13 @@ uint8_t *get_cached_data(const PageCache *cache, uint64_t
> addr);
> * cache_insert: insert the page into the cache. the page cache
> * will dup the data on insert. the previous value will be overwritten
> *
> + * Returns -1 on error
> + *
> * @cache pointer to the PageCache struct
> * @addr: page address
> * @pdata: pointer to the page
> */
> -void cache_insert(PageCache *cache, uint64_t addr, uint8_t *pdata);
> +int cache_insert(PageCache *cache, uint64_t addr, uint8_t *pdata);
>
> /**
> * cache_resize: resize the page cache. In case of size reduction the extra
> diff --git a/page_cache.c b/page_cache.c
> index 62a53f8..69e8329 100644
> --- a/page_cache.c
> +++ b/page_cache.c
> @@ -150,7 +150,7 @@ uint8_t *get_cached_data(const PageCache *cache, uint64_t
> addr)
> return cache_get_by_addr(cache, addr)->it_data;
> }
>
> -void cache_insert(PageCache *cache, uint64_t addr, uint8_t *pdata)
> +int cache_insert(PageCache *cache, uint64_t addr, uint8_t *pdata)
> {
>
> CacheItem *it = NULL;
> @@ -161,16 +161,22 @@ void cache_insert(PageCache *cache, uint64_t addr,
> uint8_t *pdata)
> /* actual update of entry */
> it = cache_get_by_addr(cache, addr);
>
> - /* free old cached data if any */
> - g_free(it->it_data);
> -
> + /* allocate page */
> if (!it->it_data) {
> cache->num_items++;
> + it->it_data = g_try_malloc(cache->page_size);
> + if (!it->it_data) {
> + DPRINTF("Error allocating page\n");
> + return -1;
> + }
It feels like it would have been correct to do the num_items++ after the
allocation test (although since the num_items doesn't seem to be used
anywhere that's not a show-stopper, but worth fixing sometime).
> }
>
> - it->it_data = g_memdup(pdata, cache->page_size);
> + memcpy(it->it_data, pdata, cache->page_size);
> +
> it->it_age = ++cache->max_item_age;
> it->it_addr = addr;
> +
> + return 0;
> }
>
> int64_t cache_resize(PageCache *cache, int64_t new_num_pages)
> --
> 1.8.3.1
Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
Dave
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
