[PATCH] memcg: replace in_interrupt() with !in_task()

[PATCH] memcg: replace in_interrupt() with !in_task()

[Shakeel Butt]

Replace the deprecated in_interrupt() with !in_task() because
in_interrupt() returns true for BH disabled even if the call happens in
the task context. in_task() is the right interface to differentiate
task context from NMI, hard IRQ and softirq contexts.

Signed-off-by: Shakeel Butt <shakeelb@google.com>
---
 mm/memcontrol.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d067366002e6..215dfe325e9d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2688,7 +2688,7 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
 			READ_ONCE(memcg->swap.high);
 
 		/* Don't bother a random interrupted task */
-		if (in_interrupt()) {
+		if (!in_task()) {
 			if (mem_high) {
 				schedule_work(&memcg->high_work);
 				break;
@@ -6968,7 +6968,7 @@ void mem_cgroup_sk_alloc(struct sock *sk)
 		return;
 
 	/* Do not associate the sock with unrelated interrupted task's memcg. */
-	if (in_interrupt())
+	if (!in_task())
 		return;
 
 	rcu_read_lock();
-- 
2.35.0.rc0.227.g00780c9af4-goog

Re: [PATCH] memcg: replace in_interrupt() with !in_task()

[Michal Hocko]

On Thu 27-01-22 08:26:36, Shakeel Butt wrote:
> Replace the deprecated in_interrupt() with !in_task() because
> in_interrupt() returns true for BH disabled even if the call happens in
> the task context. in_task() is the right interface to differentiate
> task context from NMI, hard IRQ and softirq contexts.

Makes sense. I do not think this will have any visible effect. Except
for removing a deprecated call, right?

> Signed-off-by: Shakeel Butt <shakeelb@google.com>

Acked-by: Michal Hocko <mhocko@suse.com>

Thanks!

> ---
>  mm/memcontrol.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index d067366002e6..215dfe325e9d 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2688,7 +2688,7 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
>  			READ_ONCE(memcg->swap.high);
>  
>  		/* Don't bother a random interrupted task */
> -		if (in_interrupt()) {
> +		if (!in_task()) {
>  			if (mem_high) {
>  				schedule_work(&memcg->high_work);
>  				break;
> @@ -6968,7 +6968,7 @@ void mem_cgroup_sk_alloc(struct sock *sk)
>  		return;
>  
>  	/* Do not associate the sock with unrelated interrupted task's memcg. */
> -	if (in_interrupt())
> +	if (!in_task())
>  		return;
>  
>  	rcu_read_lock();
> -- 
> 2.35.0.rc0.227.g00780c9af4-goog

-- 
Michal Hocko
SUSE Labs

Re: [PATCH] memcg: replace in_interrupt() with !in_task()

[Shakeel Butt]

On Fri, Jan 28, 2022 at 4:23 AM Michal Hocko <mhocko@suse.com> wrote:
>
> On Thu 27-01-22 08:26:36, Shakeel Butt wrote:
> > Replace the deprecated in_interrupt() with !in_task() because
> > in_interrupt() returns true for BH disabled even if the call happens in
> > the task context. in_task() is the right interface to differentiate
> > task context from NMI, hard IRQ and softirq contexts.
>
> Makes sense. I do not think this will have any visible effect. Except
> for removing a deprecated call, right?

Correct, that is my understanding as well.