On Wed, Apr 12, 2023 at 10:31:27PM +0800, Zqiang wrote: > The fill_page_cache_func() is invoked and start from zero to > allocate nr_pages of page, if the kfree_rcu_work() executes before > the fill_page_cache_func(), the krcp->nr_bkv_objs is updated before > enter for-loop and equal to nr_pages, since the page is allocated > first, and then check the krcp->nr_bkv_objs in put_cached_bnode(), > this produces a meaningless __get_free_page() call, this commit > therefore make allocate page start from krcp->nr_bkv_objs and > check krcp->nr_bkv_objs before allocate page. > > Signed-off-by: Zqiang <qiang1.zhang@xxxxxxxxx> > --- > kernel/rcu/tree.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index 41daae3239b5..dcb86f9f2dd6 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@ -3223,7 +3223,7 @@ static void fill_page_cache_func(struct work_struct *work) > nr_pages = atomic_read(&krcp->backoff_page_cache_fill) ? > 1 : rcu_min_cached_objs; > > - for (i = 0; i < nr_pages; i++) { > + for (i = READ_ONCE(krcp->nr_bkv_objs); i < nr_pages; i++) { > bnode = (struct kvfree_rcu_bulk_data *) > __get_free_page(GFP_KERNEL | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); > > -- > 2.32.0 > Reviewed-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx> -- Uladzislau Rezki