Re: [PATCH v2] mm: memcontrol: avoid unused function warning
From: Michal Hocko <mhocko@kernel.org>
Date: 2016-08-24 12:17:01
Also in:
linux-mm, lkml
On Wed 24-08-16 12:23:00, Arnd Bergmann wrote:
A bugfix in v4.8-rc2 introduced a harmless warning when CONFIG_MEMCG_SWAP
is disabled but CONFIG_MEMCG is enabled:
mm/memcontrol.c:4085:27: error: 'mem_cgroup_id_get_online' defined but not used [-Werror=unused-function]
static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
This moves the function inside of the #ifdef block that hides the
calling function, to avoid the warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 1f47b61fb407 ("mm: memcontrol: fix swap counter leak on swapout from offline cgroup")
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vladimir Davydov <redacted>Thanks a lot for respinning this Arnd!
quoted hunk ↗ jump to hunk
--- mm/memcontrol.c | 36 ++++++++++++++++++------------------ 1 file changed, 18 insertions(+), 18 deletions(-) This is the alternative to the original patch, as suggested by Michal Hocko. Andrew, please pick whichever version you like better.diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 2ff0289ad061..9a6a51a7c416 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c@@ -4082,24 +4082,6 @@ static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n) atomic_add(n, &memcg->id.ref); } -static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg) -{ - while (!atomic_inc_not_zero(&memcg->id.ref)) { - /* - * The root cgroup cannot be destroyed, so it's refcount must - * always be >= 1. - */ - if (WARN_ON_ONCE(memcg == root_mem_cgroup)) { - VM_BUG_ON(1); - break; - } - memcg = parent_mem_cgroup(memcg); - if (!memcg) - memcg = root_mem_cgroup; - } - return memcg; -} - static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n) { if (atomic_sub_and_test(n, &memcg->id.ref)) {@@ -5821,6 +5803,24 @@ static int __init mem_cgroup_init(void) subsys_initcall(mem_cgroup_init); #ifdef CONFIG_MEMCG_SWAP +static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg) +{ + while (!atomic_inc_not_zero(&memcg->id.ref)) { + /* + * The root cgroup cannot be destroyed, so it's refcount must + * always be >= 1. + */ + if (WARN_ON_ONCE(memcg == root_mem_cgroup)) { + VM_BUG_ON(1); + break; + } + memcg = parent_mem_cgroup(memcg); + if (!memcg) + memcg = root_mem_cgroup; + } + return memcg; +} + /** * mem_cgroup_swapout - transfer a memsw charge to swap * @page: page whose memsw charge to transfer-- 2.9.0
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