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 <tj@xxxxxxxxxx>
> Reported-by: Marc MERLIN <marc@xxxxxxxxxxx>
> Reported-by: Vlastimil Babka <vbabka@xxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
> ---
> 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;
>
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