On Wed, Sep 25, 2013 at 4:09 PM, Weijie Yang <[email protected]> wrote: > I think I find a new issue, for integrity of this mail thread, I reply > to this mail. > > It is a concurrence issue either, when duplicate store and reclaim > concurrentlly. > > zswap entry x with offset A is already stored in zswap backend. > Consider the following scenario: > > thread 0: reclaim entry x (get refcount, but not call > zswap_get_swap_cache_page) > > thread 1: store new page with the same offset A, alloc a new zswap entry y. > store finished. shrink_page_list() call __remove_mapping(), and now > it is not in swap_cache >
But I don't think swap layer will call zswap with the same offset A. > thread 0: zswap_get_swap_cache_page called. old page data is added to > swap_cache > > Now, swap cache has old data rather than new data for offset A. > error will happen If do_swap_page() get page from swap_cache. > -- Regards, --Bob -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
