[RFC PATCH 09/10] memcg: trylock stock for objcg

[Shakeel Butt]

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@xxxxxxxxx>
---
 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