Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756065AbcKVPsK (ORCPT ); Tue, 22 Nov 2016 10:48:10 -0500 Received: from mx2.suse.de ([195.135.220.15]:35220 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756046AbcKVPsJ (ORCPT ); Tue, 22 Nov 2016 10:48:09 -0500 Subject: Re: [PATCH] block,blkcg: use __GFP_NOWARN for best-effort allocations in blkcg To: Tejun Heo , Jens Axboe References: <20161121154336.GD19750@merlins.org> <0d4939f3-869d-6fb8-0914-5f74172f8519@suse.cz> <20161121215639.GF13371@merlins.org> <20161121230332.GA3767@htj.duckdns.org> Cc: linux-mm@kvack.org, Michal Hocko , Linus Torvalds , LKML , Joonsoo Kim , Marc MERLIN From: Vlastimil Babka Message-ID: <7189b1f6-98c3-9a36-83c1-79f2ff4099af@suse.cz> Date: Tue, 22 Nov 2016 16:47:49 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <20161121230332.GA3767@htj.duckdns.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2852 Lines: 80 On 11/22/2016 12:03 AM, Tejun Heo wrote: > blkcg allocates some per-cgroup data structures with GFP_NOWAIT and > when that fails falls back to operations which aren't specific to the > cgroup. Occassional failures are expected under pressure and falling > back to non-cgroup operation is the right thing to do. > > Unfortunately, I forgot to add __GFP_NOWARN to these allocations and > these expected failures end up creating a lot of noise. Add > __GFP_NOWARN. Thanks. Makes me wonder whether we should e.g. add __GFP_NOWARN to GFP_NOWAIT globally at some point. > Signed-off-by: Tejun Heo > Reported-by: Marc MERLIN > Reported-by: Vlastimil Babka Acked-by: Vlastimil Babka > --- > block/blk-cgroup.c | 9 +++++---- > block/cfq-iosched.c | 3 ++- > 2 files changed, 7 insertions(+), 5 deletions(-) > > diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c > index b08ccbb..8ba0af7 100644 > --- a/block/blk-cgroup.c > +++ b/block/blk-cgroup.c > @@ -185,7 +185,8 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg, > } > > wb_congested = wb_congested_get_create(&q->backing_dev_info, > - blkcg->css.id, GFP_NOWAIT); > + blkcg->css.id, > + GFP_NOWAIT | __GFP_NOWARN); > if (!wb_congested) { > ret = -ENOMEM; > goto err_put_css; > @@ -193,7 +194,7 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg, > > /* allocate */ > if (!new_blkg) { > - new_blkg = blkg_alloc(blkcg, q, GFP_NOWAIT); > + new_blkg = blkg_alloc(blkcg, q, GFP_NOWAIT | __GFP_NOWARN); > if (unlikely(!new_blkg)) { > ret = -ENOMEM; > goto err_put_congested; > @@ -1022,7 +1023,7 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css) > } > > spin_lock_init(&blkcg->lock); > - INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_NOWAIT); > + INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_NOWAIT | __GFP_NOWARN); > INIT_HLIST_HEAD(&blkcg->blkg_list); > #ifdef CONFIG_CGROUP_WRITEBACK > INIT_LIST_HEAD(&blkcg->cgwb_list); > @@ -1240,7 +1241,7 @@ int blkcg_activate_policy(struct request_queue *q, > if (blkg->pd[pol->plid]) > continue; > > - pd = pol->pd_alloc_fn(GFP_NOWAIT, q->node); > + pd = pol->pd_alloc_fn(GFP_NOWAIT | __GFP_NOWARN, q->node); > if (!pd) > swap(pd, pd_prealloc); > if (!pd) { > diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c > index 5e24d88..b4c3b6c 100644 > --- a/block/cfq-iosched.c > +++ b/block/cfq-iosched.c > @@ -3854,7 +3854,8 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic, > goto out; > } > > - cfqq = kmem_cache_alloc_node(cfq_pool, GFP_NOWAIT | __GFP_ZERO, > + cfqq = kmem_cache_alloc_node(cfq_pool, > + GFP_NOWAIT | __GFP_ZERO | __GFP_NOWARN, > cfqd->queue->node); > if (!cfqq) { > cfqq = &cfqd->oom_cfqq; >