To make objcg stock functions work without disabling irq, we need to
convert those function to use localtry_trylock_irqsave() instead of
localtry_lock_irqsave(). This patch for now just does the conversion and
later patch will eliminate the irq disabling code.

Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
---
 mm/memcontrol.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c803d2f5e322..ba5d004049d3 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2764,7 +2764,11 @@ static void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
 	unsigned long flags;
 	int *bytes;
 
-	localtry_lock_irqsave(&memcg_stock.stock_lock, flags);
+	if (!localtry_trylock_irqsave(&memcg_stock.stock_lock, flags)) {
+		__mod_objcg_mlstate(objcg, pgdat, idx, nr);
+		return;
+	}
+
 	stock = this_cpu_ptr(&memcg_stock);
 
 	/*
@@ -2822,7 +2826,8 @@ static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
 	unsigned long flags;
 	bool ret = false;
 
-	localtry_lock_irqsave(&memcg_stock.stock_lock, flags);
+	if (!localtry_trylock_irqsave(&memcg_stock.stock_lock, flags))
+		return ret;
 
 	stock = this_cpu_ptr(&memcg_stock);
 	if (objcg == READ_ONCE(stock->cached_objcg) && stock->nr_bytes >= nr_bytes) {
@@ -2918,7 +2923,10 @@ static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes,
 	unsigned long flags;
 	unsigned int nr_pages = 0;
 
-	localtry_lock_irqsave(&memcg_stock.stock_lock, flags);
+	if (!localtry_trylock_irqsave(&memcg_stock.stock_lock, flags)) {
+		atomic_add(nr_bytes, &objcg->nr_charged_bytes);
+		return;
+	}
 
 	stock = this_cpu_ptr(&memcg_stock);
 	if (READ_ONCE(stock->cached_objcg) != objcg) { /* reset if necessary */
-- 
2.47.1

On 2025-03-13 23:15:10 [-0700], Shakeel Butt wrote:
> To make objcg stock functions work without disabling irq, we need to
> convert those function to use localtry_trylock_irqsave() instead of
> localtry_lock_irqsave(). This patch for now just does the conversion and
> later patch will eliminate the irq disabling code.
> 
> Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
> ---
>  mm/memcontrol.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index c803d2f5e322..ba5d004049d3 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2764,7 +2764,11 @@ static void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
>  	unsigned long flags;
>  	int *bytes;
>  
> -	localtry_lock_irqsave(&memcg_stock.stock_lock, flags);
> +	if (!localtry_trylock_irqsave(&memcg_stock.stock_lock, flags)) {

Don't you need to change the of memcg_stock.stock_lock? Didn't we
introduce an explicit different type for this trylock feature?

> +		__mod_objcg_mlstate(objcg, pgdat, idx, nr);
> +		return;
> +	}
> +
>  	stock = this_cpu_ptr(&memcg_stock);
>  
>  	/*

Sebastian

On Fri, Mar 14, 2025 at 12:47:00PM +0100, Sebastian Andrzej Siewior wrote:
> On 2025-03-13 23:15:10 [-0700], Shakeel Butt wrote:
> > To make objcg stock functions work without disabling irq, we need to
> > convert those function to use localtry_trylock_irqsave() instead of
> > localtry_lock_irqsave(). This patch for now just does the conversion and
> > later patch will eliminate the irq disabling code.
> > 
> > Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
> > ---
> >  mm/memcontrol.c | 14 +++++++++++---
> >  1 file changed, 11 insertions(+), 3 deletions(-)
> > 
> > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > index c803d2f5e322..ba5d004049d3 100644
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@ -2764,7 +2764,11 @@ static void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
> >  	unsigned long flags;
> >  	int *bytes;
> >  
> > -	localtry_lock_irqsave(&memcg_stock.stock_lock, flags);
> > +	if (!localtry_trylock_irqsave(&memcg_stock.stock_lock, flags)) {
> 
> Don't you need to change the of memcg_stock.stock_lock? Didn't we
> introduce an explicit different type for this trylock feature?
> 

Yes, Alexei has already changed the type of this exact lock at [1].

[1] https://lore.kernel.org/r/20250222024427.30294-5-alexei.starovoitov@gmail.com