[PATCH 4.9 11/70] block,blkcg: use __GFP_NOWARN for best-effort allocations in blkcg

Greg Kroah-Hartman
2018-09-17T22:58:03Z

From: Tejun Heo <tj@kernel.org>

commit e00f4f4d0ff7e13b9115428a245b49108d625f09 upstream.

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.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Marc MERLIN <marc@merlins.org>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
block/blk-cgroup.c | 9 +++++----
block/cfq-iosched.c | 3 ++-
2 files changed, 7 insertions(+), 5 deletions(-)

--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -185,7 +185,8 @@ static struct blkcg_gq *blkg_create(stru
}

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(stru

/* 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_sta
}

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);
@@ -1238,7 +1239,7 @@ pd_prealloc:
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) {
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3868,7 +3868,8 @@ cfq_get_queue(struct cfq_data *cfqd, boo
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;